fix: default client fileApi is the Nexus raw tdlm-client; tell the player when the manifest cannot be fetched

The default pointed at packages.dandanton.com/tdlm-client/latest (404), so the first-launch auto install
silently did nothing. It now points at https://maven.dandanton.com/repository/tdlm-client, and a failed or
malformed manifest shows an error and opens the import wizard (same behaviour as the Start menu install).

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

.github/workflows/gradle.yml

@@ -21,63 +21,93 @@ jobs:
   build:
 
     runs-on: ubuntu-latest
+    timeout-minutes: 90
 
     steps:
     - uses: actions/checkout@v6
+
+    # Same pattern as TDLM ForestryMC/IndustrialCraft2 setup-build: cache the JDK toolchain.
     - name: Set up JDK 17
       uses: actions/setup-java@v6
       with:
         distribution: 'liberica'
         java-version: '17'
         java-package: 'jdk+fx'
+        cache-jdk: true
+
+    # Nest mirrors github.com/gradle/actions as actions/gradle-actions (also as gradle/actions).
+    # Match ForestryMC/IC2: on Gitea use cache-provider external (no setup-gradle Actions cache).
+    # Do NOT actions/cache the whole ~/.gradle/caches — that hit ~4GB here and OOM'd the
+    # Windows Docker runner on restore; siblings never cache that tree.
     - name: Setup Gradle
-      uses: gradle/actions/setup-gradle@v5
+      uses: actions/gradle-actions/setup-gradle@v6
       with:
         cache-cleanup: never
-        # Only main writes the dependency cache; pull requests read it.
+        cache-provider: ${{ github.server_url == 'https://github.com' && 'basic' || 'external' }}
-        cache-read-only: ${{ github.ref != 'refs/heads/main' }}
+
-    # The repository's wrapper downloads Gradle itself, so cache that download too.
+    # Wrapper only (small). Dependency jars re-download when cold — same as org mod CI on Gitea.
-    - name: Cache Gradle distribution
+    - name: Cache Gradle wrapper
       uses: actions/cache@v4
       with:
         path: |
           ~/.gradle/wrapper
           .gradle/wrapper-neo
-        key: gradle-dist-${{ hashFiles('gradle/wrapper/gradle-wrapper.properties', 'gradle/wrapper/GradleWrapperNeo.java') }}
+        key: gradle-wrapper-${{ runner.os }}-${{ hashFiles('gradle/wrapper/gradle-wrapper.properties', 'gradle/wrapper/GradleWrapperNeo.java') }}
-    - name: Install Xvfb
+
+    # Xvfb alone is not enough: JavaFX Glass needs GTK/X11 libs or Platform.startup fails with
+    # GtkPlatformFactory "Internal Error" and :HMCL:test can hang (looks like a checkstyle stall).
+    - name: Cache apt packages
+      uses: actions/cache@v4
+      with:
+        path: ~/apt-cache
+        key: apt-javafx-xvfb-${{ runner.os }}-${{ runner.arch }}-1
+
+    - name: Install Xvfb and JavaFX GTK deps
       run: |
-        # Installing is the slowest setup step, so skip it when the runner already has xvfb, and
+        pkgs='xvfb libgtk-3-0 libxtst6 libxxf86vm1 libgl1 libxi6 libx11-6 libxext6 libxrender1'
-        # only refresh the package index when a plain install fails.
+        sudo mkdir -p /var/cache/apt/archives/partial
-        command -v xvfb-run >/dev/null || sudo apt-get install -y --no-install-recommends xvfb \
+        if [ -d "${HOME}/apt-cache" ] && [ -n "$(ls -A "${HOME}/apt-cache" 2>/dev/null)" ]; then
-          || { sudo apt-get update && sudo apt-get install -y --no-install-recommends xvfb; }
+          sudo cp -a "${HOME}/apt-cache/." /var/cache/apt/archives/
+        fi
+        # Prefer cached debs; refresh the index only when install cannot resolve packages.
+        sudo apt-get install -y --no-install-recommends $pkgs \
+          || { sudo apt-get update && sudo apt-get install -y --no-install-recommends $pkgs; }
+        mkdir -p "${HOME}/apt-cache"
+        cp -a /var/cache/apt/archives/*.deb "${HOME}/apt-cache/" 2>/dev/null || true
+
     # One Gradle run builds, tests and runs the code and translation checks, so the
     # project is configured and compiled once instead of in two workflows.
     - name: Build and check with Gradle
       run: xvfb-run --auto-servernum ./gradlew build checkstyle checkTranslations --no-daemon --parallel
       env:
-        JAVA_TOOL_OPTIONS: -Djava.awt.headless=true
+        JAVA_TOOL_OPTIONS: -Djava.awt.headless=true -Dprism.order=sw
         MICROSOFT_AUTH_ID: ${{ secrets.MICROSOFT_AUTH_ID }}
         CURSEFORGE_API_KEY: ${{ secrets.CURSEFORGE_API_KEY }}
+
     - name: Get short SHA
       run: echo "SHORT_SHA=${GITHUB_SHA::7}" >> $GITHUB_ENV
+
     - name: Upload JAR
       uses: actions/upload-artifact@v7
       with:
         name: HMCL-${{ env.SHORT_SHA }}-jar
         path: HMCL/build/libs/HMCL-*.jar
         archive: false
+
     - name: Upload EXE
       uses: actions/upload-artifact@v7
       with:
         name: HMCL-${{ env.SHORT_SHA }}-exe
         path: HMCL/build/libs/HMCL-*.exe
         archive: false
+
     - name: Upload SH
       uses: actions/upload-artifact@v7
       with:
         name: HMCL-${{ env.SHORT_SHA }}-sh
         path: HMCL/build/libs/HMCL-*.sh
         archive: false
+
     - name: Upload DEB
       uses: actions/upload-artifact@v7
       with:

.github/workflows/publish-tdlm.yml

@@ -0,0 +1,249 @@
+name: Publish TDLM launcher
+
+# Builds HMCL.exe / HMCL.jar and publishes them for TDLMPack / players:
+#   1. Gitea Release assets (versioned download page)
+#   2. Gitea generic package tdlm-hmcl/latest (stable curl URLs)
+#
+# Mirrors TDLM/TDLMPack's pack.yml publish style (nest API host; Cloudflare
+# in front of git.potatolab.uk blocks Python urllib for large uploads).
+#
+# Auth (same name as TDLMPack pack.yml):
+#   secrets.TDLM_PACK_TOKEN — Gitea API token with package + release write.
+#   Prefer an *org* secret (like MAVEN_USER/MAVEN_PASSWORD) so HMCL inherits it;
+#   today it exists only as a TDLMPack *repo* secret unless promoted.
+#   Falls back to github.token when TDLM_PACK_TOKEN is unset (same-repo release;
+#   org generic packages may still need the pack token).
+
+on:
+  workflow_dispatch:
+    inputs:
+      release_tag:
+        description: "Release tag (also used as the release title). Example: 2026.11.08 or v3.dev-abc1234"
+        required: true
+        type: string
+  # Gitea records a push run whenever this file changes; without a push job the run
+  # fails with 0 jobs. Keep a no-op so the check is green; real publish stays dispatch-only.
+  push:
+    paths:
+      - '.github/workflows/publish-tdlm.yml'
+
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: false
+
+jobs:
+  noop:
+    if: ${{ github.event_name == 'push' }}
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo "publish-tdlm is workflow_dispatch-only; push no-op ok"
+
+  publish:
+    if: ${{ github.event_name == 'workflow_dispatch' }}
+    runs-on: ubuntu-latest
+    timeout-minutes: 90
+    steps:
+      - uses: actions/checkout@v6
+
+      # Same caching pattern as gradle.yml / TDLM ForestryMC+IC2 setup-build.
+      - name: Set up JDK 17 + JavaFX
+        uses: actions/setup-java@v6
+        with:
+          distribution: 'liberica'
+          java-version: '17'
+          java-package: 'jdk+fx'
+          cache-jdk: true
+
+      - name: Setup Gradle
+        uses: actions/gradle-actions/setup-gradle@v6
+        with:
+          cache-cleanup: never
+          cache-provider: ${{ github.server_url == 'https://github.com' && 'basic' || 'external' }}
+
+      # Wrapper only — do not cache ~/.gradle/caches (org siblings don't; ~4GB killed Docker).
+      - name: Cache Gradle wrapper
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/wrapper
+            .gradle/wrapper-neo
+          key: gradle-wrapper-${{ runner.os }}-${{ hashFiles('gradle/wrapper/gradle-wrapper.properties', 'gradle/wrapper/GradleWrapperNeo.java') }}
+
+      - name: Cache apt packages
+        uses: actions/cache@v4
+        with:
+          path: ~/apt-cache
+          key: apt-javafx-xvfb-${{ runner.os }}-${{ runner.arch }}-1
+
+      - name: Install Xvfb and JavaFX GTK deps
+        run: |
+          pkgs='xvfb libgtk-3-0 libxtst6 libxxf86vm1 libgl1 libxi6 libx11-6 libxext6 libxrender1'
+          sudo mkdir -p /var/cache/apt/archives/partial
+          if [ -d "${HOME}/apt-cache" ] && [ -n "$(ls -A "${HOME}/apt-cache" 2>/dev/null)" ]; then
+            sudo cp -a "${HOME}/apt-cache/." /var/cache/apt/archives/
+          fi
+          sudo apt-get install -y --no-install-recommends $pkgs \
+            || { sudo apt-get update && sudo apt-get install -y --no-install-recommends $pkgs; }
+          mkdir -p "${HOME}/apt-cache"
+          cp -a /var/cache/apt/archives/*.deb "${HOME}/apt-cache/" 2>/dev/null || true
+
+
+      - name: Build executables
+        run: xvfb-run --auto-servernum ./gradlew :HMCL:makeExecutables --no-daemon --parallel
+        env:
+          JAVA_TOOL_OPTIONS: -Djava.awt.headless=true -Dprism.order=sw
+          VERSION_TYPE: unofficial
+          MICROSOFT_AUTH_ID: ${{ secrets.MICROSOFT_AUTH_ID }}
+          CURSEFORGE_API_KEY: ${{ secrets.CURSEFORGE_API_KEY }}
+
+      - name: Stage stable launcher names
+        run: |
+          set -euo pipefail
+          mkdir -p build/tdlm-hmcl
+          jar="$(ls -1 HMCL/build/libs/HMCL-*.jar | grep -v '\.sha' | head -n1)"
+          exe="$(ls -1 HMCL/build/libs/HMCL-*.exe | grep -v '\.sha' | head -n1)"
+          test -n "$jar" && test -n "$exe"
+          cp -f "$jar" build/tdlm-hmcl/HMCL.jar
+          cp -f "$exe" build/tdlm-hmcl/HMCL.exe
+          # Prefer Gradle-produced checksums when present; otherwise compute.
+          if [ -f "${jar}.sha256" ]; then cp -f "${jar}.sha256" build/tdlm-hmcl/HMCL.jar.sha256
+          else sha256sum build/tdlm-hmcl/HMCL.jar | awk '{print $1}' > build/tdlm-hmcl/HMCL.jar.sha256
+          fi
+          if [ -f "${exe}.sha256" ]; then cp -f "${exe}.sha256" build/tdlm-hmcl/HMCL.exe.sha256
+          else sha256sum build/tdlm-hmcl/HMCL.exe | awk '{print $1}' > build/tdlm-hmcl/HMCL.exe.sha256
+          fi
+          echo "STAGED_JAR=$jar" >> "$GITHUB_ENV"
+          echo "STAGED_EXE=$exe" >> "$GITHUB_ENV"
+          ls -la build/tdlm-hmcl
+
+      # Stable player/CI channel: overwritten in place under tdlm-hmcl/latest.
+      - name: Publish generic package tdlm-hmcl/latest
+        env:
+          # Same secret name as TDLM/TDLMPack pack.yml (org or repo). Not MAVEN_*.
+          TDLM_PACK_TOKEN: ${{ secrets.TDLM_PACK_TOKEN }}
+          GITHUB_TOKEN: ${{ github.token }}
+          GITEA_PACKAGE_ROOT: https://git.nest.potatolab.uk:8443/api/packages/TDLM/generic/tdlm-hmcl/latest
+        run: |
+          python3 - <<'PY'
+          import os, pathlib, urllib.error, urllib.parse, urllib.request
+          token = (os.environ.get("TDLM_PACK_TOKEN") or os.environ.get("GITHUB_TOKEN") or "").strip()
+          token_src = "TDLM_PACK_TOKEN" if os.environ.get("TDLM_PACK_TOKEN", "").strip() else "github.token"
+          if not token:
+              raise SystemExit(
+                  "Need secrets.TDLM_PACK_TOKEN (promote TDLMPack's repo secret to org, like MAVEN_*) "
+                  "or a usable github.token to publish tdlm-hmcl")
+          print("auth=" + token_src)
+          upload_root = os.environ["GITEA_PACKAGE_ROOT"].rstrip("/")
+          root = pathlib.Path("build/tdlm-hmcl")
+
+          def put(name: str, data: bytes):
+              url = upload_root + "/" + urllib.parse.quote(name, safe="")
+              request = urllib.request.Request(url, data=data, method="PUT")
+              request.add_header("Authorization", "token " + token)
+              request.add_header("Content-Type", "application/octet-stream")
+              request.add_header("User-Agent", "tdlm-hmcl-publish")
+              try:
+                  with urllib.request.urlopen(request, timeout=1800) as response:
+                      response.read()
+              except urllib.error.HTTPError as exc:
+                  raise SystemExit("HTTP %s uploading %s: %s" % (exc.code, name, exc.read()[:500]))
+
+          for path in sorted(root.iterdir()):
+              if path.is_file():
+                  put(path.name, path.read_bytes())
+                  print("PACKAGE " + path.name)
+          print("generic=" + upload_root)
+          PY
+
+      # Gitea release (versioned). Nest API avoids Cloudflare blocking large urllib uploads.
+      - name: Publish Gitea release
+        env:
+          RELEASE_TAG: ${{ inputs.release_tag }}
+          TDLM_PACK_TOKEN: ${{ secrets.TDLM_PACK_TOKEN }}
+          GITHUB_TOKEN: ${{ github.token }}
+          GITEA_API_URL: https://git.nest.potatolab.uk:8443/api/v1
+          GITEA_PACKAGE_ROOT: https://git.nest.potatolab.uk:8443/api/packages/TDLM/generic/tdlm-hmcl/latest
+          TARGET_COMMIT: ${{ github.sha }}
+        run: |
+          python3 - <<'PY'
+          import json, os, urllib.error, urllib.parse, urllib.request
+          tag = os.environ["RELEASE_TAG"].strip()
+          token = (os.environ.get("TDLM_PACK_TOKEN") or os.environ.get("GITHUB_TOKEN") or "").strip()
+          token_src = "TDLM_PACK_TOKEN" if os.environ.get("TDLM_PACK_TOKEN", "").strip() else "github.token"
+          api = os.environ["GITEA_API_URL"].rstrip("/") + "/repos/TDLM/HMCL"
+          package_root = os.environ["GITEA_PACKAGE_ROOT"].rstrip("/")
+          target = os.environ.get("TARGET_COMMIT", "main").strip() or "main"
+          if not token:
+              raise SystemExit(
+                  "Need secrets.TDLM_PACK_TOKEN (org-preferred, same as TDLMPack) or github.token")
+          print("auth=" + token_src)
+          if not tag:
+              raise SystemExit("release_tag is empty")
+
+          def call(method, path, data=None, content_type="application/json", timeout=90):
+              request = urllib.request.Request(api + path, data=data, method=method)
+              request.add_header("Authorization", "token " + token)
+              request.add_header("Accept", "application/json")
+              request.add_header("User-Agent", "tdlm-hmcl-release")
+              if data is not None and content_type:
+                  request.add_header("Content-Type", content_type)
+              try:
+                  with urllib.request.urlopen(request, timeout=timeout) as response:
+                      body = response.read()
+                      return json.loads(body) if body else {}
+              except urllib.error.HTTPError as exc:
+                  if exc.code == 404:
+                      return None
+                  detail = exc.read()[:500]
+                  raise SystemExit("HTTP %s for %s: %s" % (exc.code, path, detail))
+
+          body = (
+              "TDLM/HMCL launcher binaries for players and TDLMPack.\n\n"
+              "Stable generic (overwrite in place):\n"
+              "- %s/HMCL.exe\n"
+              "- %s/HMCL.jar\n\n"
+              "TDLMPack does not Maven-resolve this launcher; point the pack README / install docs at these URLs "
+              "instead of hand-copying exe/jar.\n"
+              "Client pack fileApi default: https://packages.dandanton.com/tdlm-client/latest\n"
+              "(Pack must publish/mirror the same layout; see docs/TDLM_CONSUME.md).\n"
+          ) % (package_root, package_root)
+
+          quoted = urllib.parse.quote(tag, safe="")
+          release = call("GET", "/releases/tags/" + quoted)
+          if release and not release.get("draft"):
+              raise SystemExit("Release tag already exists: " + tag)
+          if not release:
+              release = call("POST", "/releases", json.dumps({
+                  "tag_name": tag,
+                  "name": tag,
+                  "target_commitish": target,
+                  "draft": True,
+                  "prerelease": False,
+                  "body": body,
+              }).encode("utf-8"))
+          release_id = release["id"]
+
+          staged = [
+              ("HMCL.exe", "build/tdlm-hmcl/HMCL.exe"),
+              ("HMCL.jar", "build/tdlm-hmcl/HMCL.jar"),
+              ("HMCL.exe.sha256", "build/tdlm-hmcl/HMCL.exe.sha256"),
+              ("HMCL.jar.sha256", "build/tdlm-hmcl/HMCL.jar.sha256"),
+          ]
+          for name, path in staged:
+              if not os.path.exists(path):
+                  raise SystemExit("missing " + path)
+              for old in call("GET", "/releases/%s/assets" % release_id) or []:
+                  if old.get("name") == name:
+                      call("DELETE", "/releases/%s/assets/%s" % (release_id, old["id"]))
+              with open(path, "rb") as asset:
+                  call(
+                      "POST",
+                      "/releases/%s/assets?name=%s" % (release_id, urllib.parse.quote(name)),
+                      asset.read(),
+                      "application/octet-stream",
+                      1800,
+                  )
+              print("RELEASE asset " + name)
+          call("PATCH", "/releases/%s" % release_id, json.dumps({"draft": False}).encode("utf-8"))
+          print(release.get("html_url", "Release created"))
+          PY

HMCL/src/main/java/org/jackhuang/hmcl/Metadata.java

@@ -141,18 +141,46 @@ public final class Metadata {
         return null;
     }
 
+    /// Default client Server Modpack fileApi: the Nexus raw repository `tdlm-client` read through the CDN host.
+    public static final String DEFAULT_CLIENT_FILE_API =
+            "https://maven.dandanton.com/repository/tdlm-client";
+
+    /// Stable client update root (`server-manifest.json` and `overrides/` live under this URL).
+    ///
+    /// Override with system property `hmcl.client.fileApi` or jar attribute `hmcl.client.fileApi`.
+    public static String getClientFileApi() {
+        String fromProperty = System.getProperty("hmcl.client.fileApi", "").trim();
+        if (StringUtils.isNotBlank(fromProperty)) {
+            return StringUtils.removeSuffix(fromProperty, "/");
+        }
+        String fromJar = JarUtils.getAttribute("hmcl.client.fileApi", null);
+        if (StringUtils.isNotBlank(fromJar)) {
+            return StringUtils.removeSuffix(fromJar.trim(), "/");
+        }
+        return DEFAULT_CLIENT_FILE_API;
+    }
+
+    /// Absolute URL of the client `server-manifest.json` used for first install and differential updates.
+    public static String getClientManifestUrl() {
+        return getClientFileApi() + "/server-manifest.json";
+    }
+
+    /// Fallback join address when the installed modpack manifest has no `serverAddress` / routes.
+    public static final String DEFAULT_SERVER_ADDRESS = "mc.potatolab.uk";
+
     /// Server address used when the installed modpack manifest does not provide one.
     ///
-    /// Can be set at build or run time with the `hmcl.server.address` system property; empty by default.
+    /// Override at build or run time with `-Dhmcl.server.address=…`; defaults to [#DEFAULT_SERVER_ADDRESS].
     public static String getDefaultServerAddress() {
-        return System.getProperty("hmcl.server.address", "").trim();
+        return System.getProperty("hmcl.server.address", DEFAULT_SERVER_ADDRESS).trim();
     }
 
     /// The server name shown in the title bar.
     ///
-    /// Can be set with the `hmcl.server.name` system property; empty by default.
+    /// Can be set with the `hmcl.server.name` system property; defaults to `TDLM`.
     public static String getServerName() {
-        return System.getProperty("hmcl.server.name", "").trim();
+        String name = System.getProperty("hmcl.server.name", "TDLM").trim();
+        return name.isEmpty() ? "TDLM" : name;
     }
 
 }

HMCL/src/main/java/org/jackhuang/hmcl/game/ModpackHelper.java

@@ -19,7 +19,6 @@ import org.jackhuang.hmcl.modpack.server.ServerModpackRemoteInstallTask;
 import org.jackhuang.hmcl.setting.*;
 import org.jackhuang.hmcl.task.Schedulers;
 import org.jackhuang.hmcl.task.Task;
-import org.jackhuang.hmcl.util.Lang;
 import org.jackhuang.hmcl.util.PortablePath;
 import org.jackhuang.hmcl.util.function.ExceptionalConsumer;
 import org.jackhuang.hmcl.util.function.ExceptionalRunnable;
@@ -44,6 +43,7 @@ import java.util.Set;
 
 import static org.jackhuang.hmcl.util.Lang.mapOf;
 import static org.jackhuang.hmcl.util.Pair.pair;
+import static org.jackhuang.hmcl.util.logging.Logger.LOG;
 
 /// Utilities for reading, installing, and applying modpack-specific game settings.
 @NotNullByDefault
@@ -314,18 +314,13 @@ public final class ModpackHelper {
             setting.minMemoryProperty().setValue(c.getMinMemory());
         }
 
+        // MultiMC packs are untrusted input: never auto-apply PreLaunch/Wrapper/JVM overrides.
         if (c.isOverrideCommands()) {
-            setting.getOverrideProperties().addAll(List.of(
+            LOG.warning("Ignoring MultiMC OverrideCommands (PreLaunch/Wrapper) from modpack for security");
-                    GameSettings.PROPERTY_COMMAND_WRAPPER,
-                    GameSettings.PROPERTY_PRE_LAUNCH_COMMAND
-            ));
-            setting.commandWrapperProperty().setValue(Objects.requireNonNullElse(c.getWrapperCommand(), ""));
-            setting.preLaunchCommandProperty().setValue(Objects.requireNonNullElse(c.getPreLaunchCommand(), ""));
         }
 
         if (c.isOverrideJavaArgs()) {
-            setting.getOverrideProperties().add(GameSettings.PROPERTY_JVM_OPTIONS);
+            LOG.warning("Ignoring MultiMC OverrideJavaArgs from modpack for security");
-            setting.jvmOptionsProperty().setValue(Objects.requireNonNullElse(c.getJvmArgs(), ""));
         }
 
         if (c.isOverrideConsole()) {
@@ -348,18 +343,13 @@ public final class ModpackHelper {
     }
 
     private static void applyCommandAndJvmSettings(MultiMCInstanceConfiguration c, GameSettings.Instance setting) {
+        // Same policy as toGameSettings: do not import executable commands / raw JVM args from packs.
         if (c.isOverrideCommands()) {
-            setting.getOverrideProperties().addAll(List.of(
+            LOG.warning("Ignoring MultiMC OverrideCommands (PreLaunch/Wrapper) from modpack update for security");
-                    GameSettings.PROPERTY_COMMAND_WRAPPER,
-                    GameSettings.PROPERTY_PRE_LAUNCH_COMMAND
-            ));
-            setting.commandWrapperProperty().setValue(Lang.nonNull(c.getWrapperCommand(), ""));
-            setting.preLaunchCommandProperty().setValue(Lang.nonNull(c.getPreLaunchCommand(), ""));
         }
 
         if (c.isOverrideJavaArgs()) {
-            setting.getOverrideProperties().add(GameSettings.PROPERTY_JVM_OPTIONS);
+            LOG.warning("Ignoring MultiMC OverrideJavaArgs from modpack update for security");
-            setting.jvmOptionsProperty().setValue(Lang.nonNull(c.getJvmArgs(), ""));
         }
     }
 

HMCL/src/main/java/org/jackhuang/hmcl/ui/Controllers.java

@@ -27,11 +27,16 @@ import org.jackhuang.hmcl.game.LauncherHelper;
 import org.jackhuang.hmcl.game.ModpackHelper;
 import org.jackhuang.hmcl.java.JavaManager;
 import org.jackhuang.hmcl.java.JavaRuntime;
+import org.glavo.url.WebURL;
 import org.jackhuang.hmcl.modpack.Modpack;
+import org.jackhuang.hmcl.modpack.server.ServerModpackManifest;
 import org.jackhuang.hmcl.setting.*;
+import org.jackhuang.hmcl.task.GetTask;
 import org.jackhuang.hmcl.task.Schedulers;
 import org.jackhuang.hmcl.task.Task;
 import org.jackhuang.hmcl.task.TaskExecutor;
+import org.jackhuang.hmcl.ui.download.ModpackInstallWizardProvider;
+import org.jackhuang.hmcl.util.gson.JsonUtils;
 import org.jackhuang.hmcl.ui.account.AccountListPage;
 import org.jackhuang.hmcl.ui.animation.ContainerAnimations;
 import org.jackhuang.hmcl.ui.construct.*;
@@ -354,35 +359,69 @@ public final class Controllers {
         );
     }
 
-    /// Installs the package found by [Metadata#findBundledModpackFile()] asynchronously, if present.
+    /// Installs a launcher-bundled modpack when present; otherwise, when the repository has no
-    ///
+    /// instances yet, pulls the org client [Metadata#getClientManifestUrl] and opens the install wizard.
-    /// Shows progress without a cancel action and attempts to delete the package after success.
-    /// Failures are logged; a retained package may be retried at the next startup.
     private static void tryInstallBundledModpack(HMCLGameRepository repository) {
         @Nullable Path modpackFile = Metadata.findBundledModpackFile();
-        if (modpackFile == null) {
+        if (modpackFile != null) {
+            LOG.info("Found bundled modpack at " + modpackFile + "; starting automatic install");
+
+            Controllers.taskDialog(
+                    Task.composeAsync(Schedulers.io(), () -> {
+                                Modpack modpack = ModpackHelper.readModpackManifest(modpackFile);
+                                return ModpackHelper.getInstallTask(
+                                        repository, modpackFile, new GameInstanceID(modpack.getName()), modpack, null);
+                            })
+                            .whenComplete(Schedulers.javafx(), (ignored, exception) -> {
+                                if (exception != null) {
+                                    LOG.warning("Failed to install bundled modpack", exception);
+                                    return;
+                                }
+                                try {
+                                    Files.deleteIfExists(modpackFile);
+                                } catch (IOException e) {
+                                    LOG.warning("Failed to delete bundled modpack: " + modpackFile, e);
+                                }
+                            }), i18n("modpack.installing"), TaskCancellationAction.NO_CANCEL
+            );
             return;
         }
 
-        LOG.info("Found bundled modpack at " + modpackFile + "; starting automatic install");
+        if (repository.getDisplayInstances().findAny().isPresent()) {
+            return;
+        }
 
+        String manifestUrl = Metadata.getClientManifestUrl();
+        LOG.info("No instances yet; fetching client Server Modpack from " + manifestUrl);
         Controllers.taskDialog(
-                Task.composeAsync(Schedulers.io(), () -> {
+                new GetTask(WebURL.parse(manifestUrl))
-                            Modpack modpack = ModpackHelper.readModpackManifest(modpackFile);
+                        .whenComplete(Schedulers.javafx(), (result, exception) -> {
-                            return ModpackHelper.getInstallTask(
-                                    repository, modpackFile, new GameInstanceID(modpack.getName()), modpack, null);
-                        })
-                        .whenComplete(Schedulers.javafx(), (ignored, exception) -> {
                             if (exception != null) {
-                                LOG.warning("Failed to install bundled modpack", exception);
+                                LOG.warning("Failed to fetch client Server Modpack manifest", exception);
+                                Controllers.dialog(
+                                        manifestUrl + "\n" + exception.getMessage(),
+                                        i18n("message.error"),
+                                        MessageType.ERROR);
+                                Instances.importModpack();
                                 return;
                             }
-                            try {
+                            ServerModpackManifest manifest =
-                                Files.deleteIfExists(modpackFile);
+                                    JsonUtils.fromMaybeMalformedJson(result, ServerModpackManifest.class);
-                            } catch (IOException e) {
+                            if (manifest == null) {
-                                LOG.warning("Failed to delete bundled modpack: " + modpackFile, e);
+                                LOG.warning("Malformed client Server Modpack manifest from " + manifestUrl);
+                                Controllers.dialog(
+                                        i18n("modpack.type.server.malformed"),
+                                        i18n("message.error"),
+                                        MessageType.ERROR);
+                                Instances.importModpack();
+                                return;
                             }
-                        }), i18n("modpack.installing"), TaskCancellationAction.NO_CANCEL
+                            Controllers.getDecorator().startWizard(
+                                    new ModpackInstallWizardProvider(repository, manifest),
+                                    i18n("install.modpack"));
+                        }),
+                i18n("message.downloading"),
+                TaskCancellationAction.NO_CANCEL
         );
     }
 

HMCL/src/main/java/org/jackhuang/hmcl/ui/FXUtils.java

@@ -602,6 +602,10 @@ public final class FXUtils {
             return;
 
         String url = NetworkUtils.encodeLocation(link);
+        if (!isAllowedOpenLink(url)) {
+            LOG.warning("Refusing to open link with disallowed scheme: " + link);
+            return;
+        }
         thread(() -> {
             try {
                 if (OperatingSystem.CURRENT_OS == OperatingSystem.WINDOWS) {
@@ -635,6 +639,23 @@ public final class FXUtils {
         });
     }
 
+    /// Only {@code http}/{@code https}/{@code mailto} may be handed to the OS URL handler.
+    static boolean isAllowedOpenLink(String link) {
+        try {
+            URI uri = new URI(link);
+            String scheme = uri.getScheme();
+            if (scheme == null) {
+                return false;
+            }
+            return switch (scheme.toLowerCase(java.util.Locale.ROOT)) {
+                case "http", "https", "mailto" -> true;
+                default -> false;
+            };
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
     public static <T> void bind(JFXTextField textField, Property<T> property, StringConverter<T> converter) {
         TextFieldBinding<T> binding = new TextFieldBinding<>(textField, property, converter);
         binding.updateTextField();

HMCL/src/main/java/org/jackhuang/hmcl/ui/download/ModpackInstallWizardProvider.java

@@ -28,25 +28,40 @@ public final class ModpackInstallWizardProvider implements WizardProvider {
     private final HMCLGameRepository repository;
     private final Path file;
     private final String updateVersion;
+    private final ServerModpackManifest remoteManifest;
     private String iconUrl;
     private boolean hasSource;
 
     public ModpackInstallWizardProvider(HMCLGameRepository repository) {
-        this(repository, null, null);
+        this(repository, null, null, null);
     }
 
     public ModpackInstallWizardProvider(HMCLGameRepository repository, Path modpackFile) {
-        this(repository, modpackFile, null);
+        this(repository, modpackFile, null, null);
     }
 
     public ModpackInstallWizardProvider(HMCLGameRepository repository, GameInstanceID updateInstanceId) {
-        this(repository, null, updateInstanceId);
+        this(repository, null, updateInstanceId, null);
+    }
+
+    /// Starts the wizard with a remote Server Modpack manifest (TDLM fileApi install).
+    public ModpackInstallWizardProvider(HMCLGameRepository repository, ServerModpackManifest remoteManifest) {
+        this(repository, null, null, remoteManifest);
     }
 
     public ModpackInstallWizardProvider(HMCLGameRepository repository, Path modpackFile, GameInstanceID updateInstanceId) {
+        this(repository, modpackFile, updateInstanceId, null);
+    }
+
+    private ModpackInstallWizardProvider(
+            HMCLGameRepository repository,
+            Path modpackFile,
+            GameInstanceID updateInstanceId,
+            ServerModpackManifest remoteManifest) {
         this.repository = repository;
         this.file = modpackFile;
         this.updateVersion = updateInstanceId != null ? updateInstanceId.toString() : null;
+        this.remoteManifest = remoteManifest;
     }
 
     public void setIconUrl(String iconUrl) {
@@ -57,6 +72,8 @@ public final class ModpackInstallWizardProvider implements WizardProvider {
     public void start(SettingsMap settings) {
         if (file != null)
             settings.put(LocalModpackPage.MODPACK_FILE, file);
+        if (remoteManifest != null)
+            settings.put(RemoteModpackPage.MODPACK_SERVER_MANIFEST, remoteManifest);
         if (updateVersion != null)
             settings.put(LocalModpackPage.MODPACK_NAME, updateVersion);
         if (StringUtils.isNotBlank(iconUrl))

HMCL/src/main/java/org/jackhuang/hmcl/ui/instances/Instances.java

@@ -13,6 +13,9 @@ import org.jackhuang.hmcl.download.game.GameDownloadTask;
 import org.jackhuang.hmcl.download.game.GameLibrariesTask;
 import org.jackhuang.hmcl.game.*;
 import org.jackhuang.hmcl.setting.*;
+import org.glavo.url.WebURL;
+import org.jackhuang.hmcl.modpack.server.ServerModpackManifest;
+import org.jackhuang.hmcl.task.GetTask;
 import org.jackhuang.hmcl.task.Schedulers;
 import org.jackhuang.hmcl.task.Task;
 import org.jackhuang.hmcl.ui.Controllers;
@@ -45,9 +48,10 @@ public final class Instances {
     private Instances() {
     }
 
-    /// Installs or updates the server client from the launcher-bundled modpack when present.
+    /// Installs or updates the TDLM client.
     ///
-    /// Falls back to the local/remote modpack import wizard when no bundled package is found.
+    /// Prefers a launcher-bundled zip, then the org [Metadata#getClientManifestUrl] Server Modpack,
+    /// then the generic local/remote import wizard.
     public static void installServerModpack() {
         HMCLGameRepository repository = GameDirectoryManager.getSelectedRepository();
         if (!repository.isLoaded()) {
@@ -62,7 +66,33 @@ public final class Instances {
             return;
         }
 
-        importModpack();
+        Controllers.taskDialog(
+                new GetTask(WebURL.parse(Metadata.getClientManifestUrl()))
+                        .whenComplete(Schedulers.javafx(), (result, exception) -> {
+                            if (exception != null) {
+                                Controllers.dialog(
+                                        exception.getMessage(),
+                                        i18n("message.error"),
+                                        MessageDialogPane.MessageType.ERROR);
+                                importModpack();
+                                return;
+                            }
+                            ServerModpackManifest manifest = JsonUtils.fromMaybeMalformedJson(
+                                    result, ServerModpackManifest.class);
+                            if (manifest == null) {
+                                Controllers.dialog(
+                                        i18n("modpack.type.server.malformed"),
+                                        i18n("message.error"),
+                                        MessageDialogPane.MessageType.ERROR);
+                                importModpack();
+                                return;
+                            }
+                            Controllers.getDecorator().startWizard(
+                                    new ModpackInstallWizardProvider(repository, manifest),
+                                    i18n("install.modpack"));
+                        }),
+                i18n("message.downloading"),
+                TaskCancellationAction.NORMAL);
     }
 
     public static void importModpack() {

HMCL/src/test/java/org/jackhuang/hmcl/JavaFXLauncher.java

@@ -10,6 +10,9 @@ import org.jetbrains.annotations.NotNullByDefault;
 import org.jetbrains.annotations.Nullable;
 
 import java.lang.reflect.Field;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 /// Owns the shared JavaFX toolkit for the lifetime of the test process.
 @NotNullByDefault
@@ -27,11 +30,36 @@ public final class JavaFXLauncher {
         System.setProperty("hmcl.scroll.speed", "1");
         try {
             initializeAnimationPolicy();
-            Platform.startup(() -> {
+            // Platform.startup can hang when GTK/Glass is broken (minimal CI images with only xvfb).
-            });
+            // Bound class-init so :HMCL:test cannot stall the whole Gradle build.
-            started = true;
+            CountDownLatch done = new CountDownLatch(1);
-        } catch (IllegalStateException e) {
+            AtomicReference<Throwable> error = new AtomicReference<>();
-            started = true;
+            Thread t = new Thread(() -> {
+                try {
+                    Platform.startup(() -> {
+                    });
+                } catch (Throwable e) {
+                    error.set(e);
+                } finally {
+                    done.countDown();
+                }
+            }, "hmcl-javafx-startup");
+            t.setDaemon(true);
+            t.start();
+            if (!done.await(45, TimeUnit.SECONDS)) {
+                System.err.println("JavaFX Platform.startup timed out; JavaFX tests will be skipped");
+            } else {
+                Throwable e = error.get();
+                if (e == null) {
+                    started = true;
+                } else if (e instanceof IllegalStateException) {
+                    started = true;
+                } else {
+                    e.printStackTrace();
+                }
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
         } catch (Throwable e) {
             e.printStackTrace();
         }

HMCL/src/test/java/org/jackhuang/hmcl/game/ServerEndpointTest.java

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
 package org.jackhuang.hmcl.game;
 
+import org.jackhuang.hmcl.Metadata;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
@@ -19,13 +20,15 @@ public final class ServerEndpointTest {
     }
 
     @Test
-    void noConfigurationMeansNoRoute(@TempDir Path dir) {
+    void fallsBackToBakedDefaultAddress(@TempDir Path dir) {
-        assertTrue(ServerEndpoint.routes(dir.resolve("modpack.json")).isEmpty());
+        var routes = ServerEndpoint.routes(dir.resolve("modpack.json"));
-        assertNull(ServerEndpoint.selected(dir.resolve("modpack.json")));
+        assertEquals(1, routes.size());
+        assertEquals(Metadata.DEFAULT_SERVER_ADDRESS, routes.get(0).address());
+        assertEquals(routes.get(0), ServerEndpoint.selected(dir.resolve("modpack.json")));
     }
 
     @Test
-    void fallsBackToDefaultAddress(@TempDir Path dir) {
+    void propertyOverridesBakedDefaultAddress(@TempDir Path dir) {
         System.setProperty("hmcl.server.address", " play.example.net:25565 ");
         var routes = ServerEndpoint.routes(dir.resolve("modpack.json"));
         assertEquals(1, routes.size());

HMCLBoot/src/main/java/org/jackhuang/hmcl/DesktopUtils.java

@@ -42,6 +42,11 @@ public final class DesktopUtils {
     }
 
     public static void openLink(String link) {
+        if (!isAllowedOpenLink(link)) {
+            System.err.println("Refusing to open link with disallowed scheme: " + link);
+            return;
+        }
+
         String osName = System.getProperty("os.name").toLowerCase(Locale.ROOT);
 
         Throwable e1 = null;
@@ -79,6 +84,21 @@ public final class DesktopUtils {
         }
     }
 
+    /// Only {@code http}/{@code https}/{@code mailto} may be handed to the OS URL handler.
+    static boolean isAllowedOpenLink(String link) {
+        try {
+            URI uri = new URI(link);
+            String scheme = uri.getScheme();
+            if (scheme == null) {
+                return false;
+            }
+            String lower = scheme.toLowerCase(Locale.ROOT);
+            return "http".equals(lower) || "https".equals(lower) || "mailto".equals(lower);
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
     private DesktopUtils() {
     }
 }

HMCLCore/src/main/java/org/jackhuang/hmcl/auth/authlibinjector/AuthlibInjectorServer.java

@@ -45,10 +45,18 @@ public class AuthlibInjectorServer implements Observable {
             String ali = conn.getHeaderField("x-authlib-injector-api-location");
             if (ali != null) {
                 WebURL absoluteAli = WebURL.parse(ali, WebURL.of(conn.getURL()));
+                // Only follow same-host HTTPS redirects; open redirects to other hosts are rejected.
                 if (!urlEqualsIgnoreSlash(webURL.toString(), absoluteAli.toString())) {
-                    conn.disconnect();
+                    if (!"https".equalsIgnoreCase(absoluteAli.getScheme())
-                    url = absoluteAli.toString();
+                            || absoluteAli.getHost() == null
-                    conn = NetworkUtils.resolveConnection(NetworkUtils.createHttpConnection(absoluteAli));
+                            || webURL.getHost() == null
+                            || !absoluteAli.getHost().equalsIgnoreCase(webURL.getHost())) {
+                        LOG.warning("Ignoring x-authlib-injector-api-location redirect outside original HTTPS host: " + absoluteAli);
+                    } else {
+                        conn.disconnect();
+                        url = absoluteAli.toString();
+                        conn = NetworkUtils.resolveConnection(NetworkUtils.createHttpConnection(absoluteAli));
+                    }
                 }
             }
 

HMCLCore/src/main/java/org/jackhuang/hmcl/game/LaunchOptions.java

@@ -327,6 +327,10 @@ public class LaunchOptions implements Serializable {
             return this;
         }
 
+        public Path getGameDir() {
+            return options.gameDir;
+        }
+
         public Builder setJava(JavaRuntime java) {
             options.java = java;
             return this;

HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/multimc/MultiMCInstancePatch.java

@@ -7,6 +7,7 @@ import com.google.gson.annotations.SerializedName;
 
 import org.jackhuang.hmcl.game.*;
 import org.jackhuang.hmcl.util.Immutable;
+import org.jackhuang.hmcl.util.JvmArgumentFilter;
 import org.jackhuang.hmcl.util.Lang;
 import org.jackhuang.hmcl.util.StringUtils;
 import org.jackhuang.hmcl.util.gson.JsonUtils;
@@ -282,7 +283,7 @@ public final class MultiMCInstancePatch {
             if (minecraftArguments == null & patch.getMinecraftArguments() != null) {
                 minecraftArguments = StringUtils.tokenize(patch.getMinecraftArguments());
             }
-            for (String jvmArg : patch.getJvmArgs()) {
+            for (String jvmArg : JvmArgumentFilter.filter(patch.getJvmArgs())) {
                 jvmArguments.add(new StringArgument(jvmArg));
             }
             mainClass = Lang.requireNonNullElse(mainClass, patch.getMainClass());

HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/server/Lwjgl3ifyApplyTask.java

@@ -0,0 +1,220 @@
+// SPDX-FileCopyrightText: Copyright (C) 2026 The HMCL Authors
+// SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
+package org.jackhuang.hmcl.modpack.server;
+
+import org.jackhuang.hmcl.download.DefaultDependencyManager;
+import org.jackhuang.hmcl.download.game.GameAssetDownloadTask;
+import org.jackhuang.hmcl.download.game.GameDownloadTask;
+import org.jackhuang.hmcl.download.game.GameLibrariesTask;
+import org.jackhuang.hmcl.game.*;
+import org.jackhuang.hmcl.modpack.multimc.MultiMCComponents;
+import org.jackhuang.hmcl.modpack.multimc.MultiMCInstancePatch;
+import org.jackhuang.hmcl.modpack.multimc.MultiMCManifest;
+import org.jackhuang.hmcl.task.GetTask;
+import org.jackhuang.hmcl.task.Task;
+import org.jackhuang.hmcl.util.Lang;
+import org.jackhuang.hmcl.util.io.FileUtils;
+import org.jetbrains.annotations.NotNullByDefault;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.util.*;
+
+/// Applies the default-on lwjgl3ify MultiMC companion under {@link Lwjgl3ifySupport#ROOT}.
+///
+/// Replaces the plain Forge install produced by {@link org.jackhuang.hmcl.download.GameBuilder} with the
+/// resolved MultiMC artifact (libraries, JVM args, bootstrap main class) so Java 25 launches work
+/// without a player toggle.
+@NotNullByDefault
+public final class Lwjgl3ifyApplyTask extends Task<Void> {
+    private final DefaultDependencyManager dependencyManager;
+    private final DefaultGameRepository repository;
+    private final GameInstanceID instanceId;
+    private final @Nullable DefaultGameInstance updateTarget;
+    private final List<Task<?>> dependents = new ArrayList<>();
+    private final List<Task<?>> dependencies = new ArrayList<>();
+    private @Nullable MultiMCInstancePatch.ResolvedInstance artifact;
+
+    public Lwjgl3ifyApplyTask(
+            DefaultDependencyManager dependencyManager,
+            GameInstanceID instanceId,
+            @Nullable DefaultGameInstance updateTarget) {
+        this.dependencyManager = dependencyManager;
+        this.repository = dependencyManager.getGameRepository();
+        this.instanceId = instanceId;
+        this.updateTarget = updateTarget;
+        setStage("hmcl.modpack");
+        setSignificance(TaskSignificance.MODERATE);
+
+        Path instanceRoot = repository.getLayout().getInstanceRoot(instanceId);
+        if (!Lwjgl3ifySupport.isPresent(instanceRoot)) {
+            return;
+        }
+
+        try {
+            dependents.add(new AssemblePatchesTask(instanceRoot));
+        } catch (IOException e) {
+            dependents.add(Task.failed(e));
+        }
+    }
+
+    /// Runs after Server Modpack file sync when the companion is present; otherwise a completed no-op.
+    public static Task<?> afterCompletion(DefaultDependencyManager dependencyManager, DefaultGameInstance instance) {
+        if (!Lwjgl3ifySupport.isPresent(instance.getInstanceRoot())) {
+            return Task.completed(null);
+        }
+        return new Lwjgl3ifyApplyTask(dependencyManager, instance.getId(), instance);
+    }
+
+    @Override
+    public List<Task<?>> getDependents() {
+        return dependents;
+    }
+
+    @Override
+    public List<Task<?>> getDependencies() {
+        return dependencies;
+    }
+
+    @Override
+    public void execute() throws Exception {
+        Path instanceRoot = repository.getLayout().getInstanceRoot(instanceId);
+        if (!Lwjgl3ifySupport.isPresent(instanceRoot)) {
+            return;
+        }
+
+        @Nullable AssemblePatchesTask assemble = null;
+        for (Task<?> dependent : dependents) {
+            if (dependent instanceof AssemblePatchesTask patchesTask) {
+                assemble = patchesTask;
+                break;
+            }
+        }
+        Objects.requireNonNull(assemble, "lwjgl3ify patch assemble task");
+        artifact = MultiMCInstancePatch.resolveArtifact(assemble.getResult(), instanceId);
+
+        Path embeddedLibraries = Lwjgl3ifySupport.root(instanceRoot).resolve("libraries");
+        if (Files.isDirectory(embeddedLibraries)) {
+            FileUtils.copyDirectory(embeddedLibraries, instanceRoot.resolve("libraries"));
+        }
+
+        for (Library library : artifact.getManifest().getLibraries()) {
+            if ("local".equals(library.hint())) {
+                Path from = repository.getLayout().getLibraryFile(artifact.getManifest().id(), library);
+                Path target = repository.getLayout().getLibraryFile(artifact.getManifest().id(), library.withoutCommunityFields());
+                if (Files.exists(from)) {
+                    Files.createDirectories(target.getParent());
+                    Files.copy(from, target, StandardCopyOption.REPLACE_EXISTING);
+                }
+            }
+        }
+
+        try (InputStream input = Objects.requireNonNull(
+                Lwjgl3ifyApplyTask.class.getResourceAsStream("/assets/game/HMCLMultiMCBootstrap-1.0.jar"),
+                "Bundled HMCLMultiMCBootstrap is missing.")) {
+            Path libraryPath = repository.getLayout().getLibraryFile(artifact.getManifest().id(), MultiMCInstancePatch.BOOTSTRAP_LIBRARY);
+            Files.createDirectories(libraryPath.getParent());
+            Files.copy(input, libraryPath, StandardCopyOption.REPLACE_EXISTING);
+        }
+
+        GameInstanceManifest instanceManifest = artifact.getManifest();
+        repository.save(instanceManifest);
+
+        dependencies.add(new GameAssetDownloadTask(dependencyManager, instanceManifest, GameAssetDownloadTask.DOWNLOAD_INDEX_FORCIBLY, true));
+        dependencies.add(new GameLibrariesTask(
+                dependencyManager,
+                instanceManifest.withLibraries(Lang.merge(instanceManifest.getLibraries(), artifact.getMavenOnlyFiles())),
+                true));
+
+        Path instanceJar = getPrimaryJarFile();
+        dependencies.add(new GameDownloadTask(dependencyManager, instanceManifest)
+                .thenAcceptAsync(cachedJar -> FileUtils.copyFile(cachedJar, instanceJar))
+                .withStage("hmcl.modpack.download"));
+    }
+
+    private Path getPrimaryJarFile() {
+        if (updateTarget == null) {
+            return repository.getLayout().getInstanceJarFile(instanceId);
+        }
+        Path manifestFile = updateTarget.getManifestFile();
+        return manifestFile.resolveSibling(FileUtils.getNameWithoutExtension(manifestFile) + ".jar");
+    }
+
+    private static final class AssemblePatchesTask extends Task<List<MultiMCInstancePatch>> {
+        private final Path companionRoot;
+        private final String mcVersion;
+        private final List<Task<MultiMCInstancePatch>> patches = new ArrayList<>();
+
+        AssemblePatchesTask(Path instanceRoot) throws IOException {
+            this.companionRoot = Lwjgl3ifySupport.root(instanceRoot);
+            MultiMCManifest mmcPack = Lwjgl3ifySupport.readMmcPack(instanceRoot);
+            List<MultiMCManifest.MultiMCManifestComponent> components = Objects.requireNonNull(
+                    mmcPack.getComponents(), "components");
+
+            String resolvedMc = null;
+            for (MultiMCManifest.MultiMCManifestComponent component : components) {
+                if (MultiMCComponents.getComponent(component.getUid()) == GameComponentType.GAME) {
+                    resolvedMc = component.getVersion();
+                    break;
+                }
+            }
+            if (resolvedMc == null) {
+                throw new IOException("lwjgl3ify mmc-pack.json has no Minecraft component");
+            }
+            this.mcVersion = resolvedMc;
+
+            for (MultiMCManifest.MultiMCManifestComponent component : components) {
+                String componentID = Objects.requireNonNull(component.getUid(), "Component ID");
+                Path patchPath = companionRoot.resolve("patches").resolve(componentID + ".json");
+                if (Files.isRegularFile(patchPath)) {
+                    MultiMCInstancePatch patch = MultiMCInstancePatch.read(componentID, Files.readString(patchPath));
+                    patches.add(Task.supplyAsync(() -> patch));
+                } else {
+                    patches.add(new GetTask(MultiMCComponents.getMetaURL(componentID, component.getVersion(), mcVersion))
+                            .thenApplyAsync(s -> MultiMCInstancePatch.read(componentID, s)));
+                }
+            }
+        }
+
+        @Override
+        public Collection<? extends Task<?>> getDependents() {
+            return patches;
+        }
+
+        @Override
+        public void execute() throws Exception {
+            Map<String, MultiMCInstancePatch> existed = new LinkedHashMap<>();
+            for (Task<MultiMCInstancePatch> patch : patches) {
+                MultiMCInstancePatch result = patch.getResult();
+                existed.put(result.getID(), result);
+            }
+
+            checking:
+            while (true) {
+                for (MultiMCInstancePatch patch : existed.values()) {
+                    for (MultiMCManifest.MultiMCManifestCachedRequires require : patch.getRequires()) {
+                        String componentID = require.getID();
+                        if (!existed.containsKey(componentID)) {
+                            Task<MultiMCInstancePatch> task = new GetTask(MultiMCComponents.getMetaURL(
+                                    componentID,
+                                    Lang.requireNonNullElse(require.getEqualsVersion(), require.getSuggests()),
+                                    mcVersion
+                            )).thenApplyAsync(s -> MultiMCInstancePatch.read(componentID, s));
+                            task.run();
+                            MultiMCInstancePatch result = Objects.requireNonNull(task.getResult());
+                            existed.put(result.getID(), result);
+                            continue checking;
+                        }
+                    }
+                }
+                break;
+            }
+
+            setResult(new ArrayList<>(existed.values()));
+        }
+    }
+}

HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/server/Lwjgl3ifySupport.java

@@ -0,0 +1,80 @@
+// SPDX-FileCopyrightText: Copyright (C) 2026 The HMCL Authors
+// SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
+package org.jackhuang.hmcl.modpack.server;
+
+import org.jackhuang.hmcl.game.LaunchOptions;
+import org.jackhuang.hmcl.modpack.multimc.MultiMCInstancePatch;
+import org.jackhuang.hmcl.modpack.multimc.MultiMCManifest;
+import org.jackhuang.hmcl.util.JvmArgumentFilter;
+import org.jackhuang.hmcl.util.gson.JsonUtils;
+import org.jetbrains.annotations.NotNullByDefault;
+
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.jackhuang.hmcl.util.logging.Logger.LOG;
+
+/// Default-on lwjgl3ify companion shipped under {@code tdlm/lwjgl3ify/} in the TDLM Server Modpack.
+@NotNullByDefault
+public final class Lwjgl3ifySupport {
+    /// Instance-root-relative directory written by the TDLM pack builder.
+    public static final String ROOT = "tdlm/lwjgl3ify";
+
+    private Lwjgl3ifySupport() {
+    }
+
+    /// Returns whether the instance carries an enabled lwjgl3ify MultiMC companion.
+    public static boolean isPresent(Path instanceRoot) {
+        Path root = root(instanceRoot);
+        return Files.isRegularFile(root.resolve("enabled")) && Files.isRegularFile(root.resolve("mmc-pack.json"));
+    }
+
+    /// Returns the companion root under the instance.
+    public static Path root(Path instanceRoot) {
+        return instanceRoot.resolve(ROOT);
+    }
+
+    /// Injects {@code +jvmArgs} from every local patch when the companion is present.
+    ///
+    /// Version-json application via {@link Lwjgl3ifyApplyTask} is the primary path; this covers launches
+    /// where the resolved manifest has not yet absorbed those args.
+    public static void injectLaunchOptions(Path instanceRoot, LaunchOptions.Builder builder) {
+        if (!isPresent(instanceRoot)) {
+            return;
+        }
+        Path patches = root(instanceRoot).resolve("patches");
+        if (!Files.isDirectory(patches)) {
+            return;
+        }
+        List<String> args = new ArrayList<>();
+        try (DirectoryStream<Path> stream = Files.newDirectoryStream(patches, "*.json")) {
+            for (Path patchFile : stream) {
+                try {
+                    MultiMCInstancePatch patch = MultiMCInstancePatch.read(
+                            patchFile.getFileName().toString(), Files.readString(patchFile));
+                    args.addAll(JvmArgumentFilter.filter(patch.getJvmArgs()));
+                } catch (IOException | RuntimeException e) {
+                    LOG.warning("Failed to read lwjgl3ify patch " + patchFile, e);
+                }
+            }
+        } catch (IOException e) {
+            LOG.warning("Failed to list lwjgl3ify patches under " + patches, e);
+            return;
+        }
+        for (String arg : args) {
+            if (!builder.getJavaArguments().contains(arg)) {
+                builder.getJavaArguments().add(arg);
+            }
+        }
+    }
+
+    /// Parses {@code mmc-pack.json} from the companion root.
+    public static MultiMCManifest readMmcPack(Path instanceRoot) throws IOException {
+        Path mmcPack = root(instanceRoot).resolve("mmc-pack.json");
+        return JsonUtils.fromNonNullJson(Files.readString(mmcPack), MultiMCManifest.class);
+    }
+}

HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/server/ServerModpackLocalInstallTask.java

@@ -32,6 +32,7 @@ public class ServerModpackLocalInstallTask extends Task<Void> {
     /// Existing instance selecting update mode, or `null` for a new installation.
     private final @Nullable DefaultGameInstance updateTarget;
 
+    private final DefaultDependencyManager dependencyManager;
     private final DefaultGameRepository repository;
     private final List<Task<?>> dependencies = new ArrayList<>();
     private final List<Task<?>> dependents = new ArrayList<>(4);
@@ -97,6 +98,7 @@ public class ServerModpackLocalInstallTask extends Task<Void> {
         this.manifest = manifest;
         this.instanceId = instanceId;
         this.updateTarget = updateTarget;
+        this.dependencyManager = dependencyManager;
         this.repository = dependencyManager.getGameRepository();
         Path run = repository.getLayout().getInstanceRoot(instanceId);
 
@@ -148,5 +150,9 @@ public class ServerModpackLocalInstallTask extends Task<Void> {
 
     @Override
     public void execute() throws Exception {
+        Path instanceRoot = repository.getLayout().getInstanceRoot(instanceId);
+        if (Lwjgl3ifySupport.isPresent(instanceRoot)) {
+            dependencies.add(new Lwjgl3ifyApplyTask(dependencyManager, instanceId, updateTarget));
+        }
     }
 }

HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/server/ServerModpackProvider.java

@@ -6,6 +6,7 @@ import com.google.gson.JsonParseException;
 import kala.compress.archivers.zip.ZipArchiveReader;
 import org.jackhuang.hmcl.download.DefaultDependencyManager;
 import org.jackhuang.hmcl.game.DefaultGameInstance;
+import org.jackhuang.hmcl.game.LaunchOptions;
 import org.jackhuang.hmcl.modpack.MismatchedModpackTypeException;
 import org.jackhuang.hmcl.modpack.Modpack;
 import org.jackhuang.hmcl.modpack.ModpackProvider;
@@ -29,7 +30,8 @@ public final class ServerModpackProvider implements ModpackProvider {
 
     @Override
     public Task<?> createCompletionTask(DefaultDependencyManager dependencyManager, DefaultGameInstance instance) {
-        return new ServerModpackCompletionTask(dependencyManager, instance);
+        return new ServerModpackCompletionTask(dependencyManager, instance)
+                .thenComposeAsync(ignored -> Lwjgl3ifyApplyTask.afterCompletion(dependencyManager, instance));
     }
 
     @Override
@@ -51,4 +53,12 @@ public final class ServerModpackProvider implements ModpackProvider {
         ServerModpackManifest manifest = JsonUtils.fromNonNullJson(json, ServerModpackManifest.class);
         return manifest.toModpack();
     }
+
+    @Override
+    public void injectLaunchOptions(String modpackConfigurationJson, LaunchOptions.Builder builder) {
+        Path gameDir = builder.getGameDir();
+        if (gameDir != null) {
+            Lwjgl3ifySupport.injectLaunchOptions(gameDir, builder);
+        }
+    }
 }

HMCLCore/src/main/java/org/jackhuang/hmcl/modpack/server/ServerModpackRemoteInstallTask.java

@@ -126,10 +126,12 @@ public class ServerModpackRemoteInstallTask extends Task<Void> {
 
     @Override
     public void execute() throws Exception {
+        DefaultGameInstance instance = repository.getInstance(instanceId);
         dependencies.add(new ServerModpackCompletionTask(
                 dependency,
-                repository.getInstance(instanceId),
+                instance,
-                new ModpackConfiguration<>(manifest, MODPACK_TYPE, manifest.getName(), manifest.getVersion(), Collections.emptyList())));
+                new ModpackConfiguration<>(manifest, MODPACK_TYPE, manifest.getName(), manifest.getVersion(), Collections.emptyList()))
+                .thenComposeAsync(ignored -> Lwjgl3ifyApplyTask.afterCompletion(dependency, instance)));
     }
 
     public static final String MODPACK_TYPE = "Server";

HMCLCore/src/main/java/org/jackhuang/hmcl/util/JvmArgumentFilter.java

@@ -0,0 +1,57 @@
+// SPDX-FileCopyrightText: Copyright (C) 2026 The HMCL Authors
+// SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
+package org.jackhuang.hmcl.util;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+import static org.jackhuang.hmcl.util.logging.Logger.LOG;
+
+/**
+ * Filters JVM arguments coming from untrusted modpack / MultiMC patch input.
+ *
+ * <p>Denies agent injection and {@code -XX:On*Error} command hooks while allowing ordinary
+ * memory / GC / system-property args used by companions such as lwjgl3ify.
+ */
+public final class JvmArgumentFilter {
+    private JvmArgumentFilter() {
+    }
+
+    /// Returns whether a single JVM argument is safe to accept from modpack / patch metadata.
+    public static boolean isAllowed(@Nullable String arg) {
+        if (arg == null) {
+            return false;
+        }
+        String trimmed = arg.trim();
+        if (trimmed.isEmpty()) {
+            return false;
+        }
+        String lower = trimmed.toLowerCase(Locale.ROOT);
+        if (lower.startsWith("-javaagent")
+                || lower.startsWith("-agentpath")
+                || lower.startsWith("-agentlib")
+                || lower.startsWith("-xbootclasspath")
+                || lower.startsWith("-xx:onoutofmemoryerror")
+                || lower.startsWith("-xx:onerror")
+                || lower.startsWith("-xx:exitonoutofmemoryerror")) {
+            return false;
+        }
+        return true;
+    }
+
+    /// Copies {@code args}, dropping disallowed entries and logging each skip.
+    public static List<String> filter(Iterable<String> args) {
+        List<String> out = new ArrayList<>();
+        for (String arg : args) {
+            if (isAllowed(arg)) {
+                out.add(arg);
+            } else {
+                LOG.warning("Ignoring disallowed JVM argument from modpack/patch: " + arg);
+            }
+        }
+        return out;
+    }
+}

HMCLCore/src/main/java/org/jackhuang/hmcl/util/io/FileUtils.java

@@ -306,6 +306,7 @@ public final class FileUtils {
     }
 
     public static void copyDirectory(Path src, Path dest, Predicate<String> filePredicate) throws IOException {
+        Path destRoot = dest.toAbsolutePath().normalize();
         Files.walkFileTree(src, new SimpleFileVisitor<>() {
             @Override
             public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
@@ -313,7 +314,11 @@ public final class FileUtils {
                     return FileVisitResult.SKIP_SUBTREE;
                 }
 
-                Path destFile = dest.resolve(src.relativize(file).toString());
+                Path destFile = destRoot.resolve(src.relativize(file).toString()).toAbsolutePath().normalize();
+                if (!destFile.startsWith(destRoot)) {
+                    throw new IOException("Refusing to copy outside destination directory: " + file);
+                }
+                Files.createDirectories(destFile.getParent());
                 Files.copy(file, destFile, StandardCopyOption.REPLACE_EXISTING);
                 return FileVisitResult.CONTINUE;
             }
@@ -324,7 +329,10 @@ public final class FileUtils {
                     return FileVisitResult.SKIP_SUBTREE;
                 }
 
-                Path destDir = dest.resolve(src.relativize(dir).toString());
+                Path destDir = destRoot.resolve(src.relativize(dir).toString()).toAbsolutePath().normalize();
+                if (!destDir.startsWith(destRoot)) {
+                    throw new IOException("Refusing to create directory outside destination: " + dir);
+                }
                 Files.createDirectories(destDir);
                 return FileVisitResult.CONTINUE;
             }

HMCLCore/src/main/java/org/jackhuang/hmcl/util/io/HttpRequest.java

@@ -10,6 +10,7 @@ import org.jackhuang.hmcl.util.function.ExceptionalSupplier;
 import org.jackhuang.hmcl.util.gson.JsonUtils;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
@@ -134,9 +135,10 @@ public abstract class HttpRequest {
                 con = resolveConnection(con);
                 checkResponseCode(con);
 
-                return IOUtils.readFullyAsString("gzip".equals(con.getContentEncoding())
+                InputStream body = "gzip".equals(con.getContentEncoding())
                         ? IOUtils.wrapFromGZip(con.getInputStream())
-                        : con.getInputStream());
+                        : con.getInputStream();
+                return IOUtils.readFullyAsString(body, UTF_8, IOUtils.DEFAULT_MAX_HTTP_BODY_BYTES);
             }, retryTimes);
         }
     }

HMCLCore/src/main/java/org/jackhuang/hmcl/util/io/IOUtils.java

@@ -5,7 +5,13 @@ package org.jackhuang.hmcl.util.io;
 import kala.encdet.EncodingDetector;
 import org.jetbrains.annotations.Nullable;
 
-import java.io.*;
+import java.io.BufferedReader;
+import java.io.ByteArrayOutputStream;
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
 import java.nio.ByteBuffer;
 import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
@@ -29,6 +35,9 @@ public final class IOUtils {
 
     public static final int DEFAULT_BUFFER_SIZE = 32 * 1024;
 
+    /// Soft cap for HTTP / metadata bodies read into memory (authlib, API JSON, etc.).
+    public static final long DEFAULT_MAX_HTTP_BODY_BYTES = 16L * 1024L * 1024L;
+
     public static BufferedReader newBufferedReaderMaybeNativeEncoding(Path file) throws IOException {
         if (NATIVE_CHARSET == UTF_8)
             return Files.newBufferedReader(file);
@@ -68,8 +77,29 @@ public final class IOUtils {
     }
 
     public static byte[] readFully(InputStream stream) throws IOException {
+        return readFully(stream, -1L);
+    }
+
+    /// Reads the stream fully, optionally refusing bodies larger than {@code maxBytes}.
+    ///
+    /// @param maxBytes maximum accepted size, or {@code <= 0} for no limit
+    public static byte[] readFully(InputStream stream, long maxBytes) throws IOException {
         try (stream) {
-            return stream.readAllBytes();
+            if (maxBytes <= 0) {
+                return stream.readAllBytes();
+            }
+            ByteArrayOutputStream out = new ByteArrayOutputStream(Math.min(DEFAULT_BUFFER_SIZE, (int) Math.min(maxBytes, Integer.MAX_VALUE)));
+            byte[] buf = new byte[DEFAULT_BUFFER_SIZE];
+            long total = 0;
+            int n;
+            while ((n = stream.read(buf)) >= 0) {
+                total += n;
+                if (total > maxBytes) {
+                    throw new IOException("Response body exceeds limit of " + maxBytes + " bytes");
+                }
+                out.write(buf, 0, n);
+            }
+            return out.toByteArray();
         }
     }
 
@@ -81,6 +111,10 @@ public final class IOUtils {
         return new String(readFully(stream), charset);
     }
 
+    public static String readFullyAsString(InputStream stream, Charset charset, long maxBytes) throws IOException {
+        return new String(readFully(stream, maxBytes), charset);
+    }
+
     public static void skipNBytes(InputStream input, long n) throws IOException {
         while (n > 0) {
             long ns = input.skip(n);

HMCLCore/src/main/java/org/jackhuang/hmcl/util/io/NetworkUtils.java

@@ -437,13 +437,13 @@ public final class NetworkUtils {
             Charset charset = getCharsetFromContentType(con.getHeaderField("Content-Type"));
 
             try (InputStream stdout = con.getInputStream()) {
-                return IOUtils.readFullyAsString(contentEncoding.wrap(stdout), charset);
+                return IOUtils.readFullyAsString(contentEncoding.wrap(stdout), charset, IOUtils.DEFAULT_MAX_HTTP_BODY_BYTES);
             } catch (IOException e) {
                 if (con instanceof HttpURLConnection) {
                     try (InputStream stderr = ((HttpURLConnection) con).getErrorStream()) {
                         if (stderr == null)
                             throw e;
-                        return IOUtils.readFullyAsString(contentEncoding.wrap(stderr), charset);
+                        return IOUtils.readFullyAsString(contentEncoding.wrap(stderr), charset, IOUtils.DEFAULT_MAX_HTTP_BODY_BYTES);
                     }
                 } else {
                     throw e;

HMCLCore/src/test/java/org/jackhuang/hmcl/JavaFXLauncher.java

@@ -2,6 +2,10 @@
 // SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
 package org.jackhuang.hmcl;
 
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
 public final class JavaFXLauncher {
 
     private JavaFXLauncher() {
@@ -10,13 +14,37 @@ public final class JavaFXLauncher {
     private static boolean started = false;
 
     static {
-        // init JavaFX Toolkit
+        // init JavaFX Toolkit — never block class init forever if GTK/Glass hangs under CI.
         try {
-            javafx.application.Platform.startup(() -> {
+            CountDownLatch done = new CountDownLatch(1);
-            });
+            AtomicReference<Throwable> error = new AtomicReference<>();
-            started = true;
+            Thread t = new Thread(() -> {
-        } catch (IllegalStateException e) {
+                try {
-            started = true;
+                    javafx.application.Platform.startup(() -> {
+                    });
+                } catch (Throwable e) {
+                    error.set(e);
+                } finally {
+                    done.countDown();
+                }
+            }, "hmcl-javafx-startup");
+            t.setDaemon(true);
+            t.start();
+            if (!done.await(45, TimeUnit.SECONDS)) {
+                System.err.println("JavaFX Platform.startup timed out; JavaFX tests will be skipped");
+            } else {
+                Throwable e = error.get();
+                if (e == null) {
+                    started = true;
+                } else if (e instanceof IllegalStateException) {
+                    // Toolkit already running in this JVM.
+                    started = true;
+                } else {
+                    e.printStackTrace();
+                }
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
         } catch (Throwable e) {
             e.printStackTrace();
         }

HMCLCore/src/test/java/org/jackhuang/hmcl/util/JvmArgumentFilterTest.java

@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: Copyright (C) 2026 The HMCL Authors
+// SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
+package org.jackhuang.hmcl.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class JvmArgumentFilterTest {
+    @Test
+    public void allowsOrdinaryArgs() {
+        assertTrue(JvmArgumentFilter.isAllowed("-Xmx2G"));
+        assertTrue(JvmArgumentFilter.isAllowed("-Djava.library.path=/tmp"));
+        assertTrue(JvmArgumentFilter.isAllowed("--add-opens=java.base/java.lang=ALL-UNNAMED"));
+    }
+
+    @Test
+    public void rejectsAgentsAndOnErrorHooks() {
+        assertFalse(JvmArgumentFilter.isAllowed("-javaagent:/tmp/evil.jar"));
+        assertFalse(JvmArgumentFilter.isAllowed("-agentpath:/tmp/evil.so"));
+        assertFalse(JvmArgumentFilter.isAllowed("-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005"));
+        assertFalse(JvmArgumentFilter.isAllowed("-Xbootclasspath/a:/tmp/evil.jar"));
+        assertFalse(JvmArgumentFilter.isAllowed("-XX:OnOutOfMemoryError=curl evil.example"));
+        assertFalse(JvmArgumentFilter.isAllowed("-XX:OnError=id"));
+    }
+
+    @Test
+    public void filterDropsDisallowed() {
+        assertEquals(List.of("-Xmx1G"),
+                JvmArgumentFilter.filter(List.of("-Xmx1G", "-javaagent:x.jar")));
+    }
+}

HMCLCore/src/test/java/org/jackhuang/hmcl/util/io/CopyDirectoryTraversalTest.java

@@ -0,0 +1,36 @@
+// SPDX-FileCopyrightText: Copyright (C) 2026 The HMCL Authors
+// SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
+package org.jackhuang.hmcl.util.io;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class CopyDirectoryTraversalTest {
+    @TempDir
+    Path temp;
+
+    @Test
+    public void copiesWithinDestination() throws IOException {
+        Path src = temp.resolve("src");
+        Path dest = temp.resolve("dest");
+        Files.createDirectories(src.resolve("a"));
+        Files.writeString(src.resolve("a/b.txt"), "hi");
+        FileUtils.copyDirectory(src, dest);
+        assertEquals("hi", Files.readString(dest.resolve("a/b.txt")));
+    }
+
+    @Test
+    public void destinationRootGuardMatchesUnzipperStyle() {
+        Path destRoot = temp.resolve("dest").toAbsolutePath().normalize();
+        Path escape = destRoot.resolve("sub/../../outside.txt").toAbsolutePath().normalize();
+        assertFalse(escape.startsWith(destRoot), "normalize + startsWith must reject escapes");
+        Path inside = destRoot.resolve("sub/file.txt").toAbsolutePath().normalize();
+        assertTrue(inside.startsWith(destRoot));
+    }
+}

HMCLCore/src/test/java/org/jackhuang/hmcl/util/io/IOUtilsReadLimitTest.java

@@ -0,0 +1,26 @@
+// SPDX-FileCopyrightText: Copyright (C) 2026 The HMCL Authors
+// SPDX-License-Identifier: GPL-3.0-or-later WITH AdditionRef-HMCL
+package org.jackhuang.hmcl.util.io;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class IOUtilsReadLimitTest {
+    @Test
+    public void rejectsOversizedBody() {
+        byte[] data = new byte[100];
+        assertThrows(IOException.class, () -> IOUtils.readFully(new ByteArrayInputStream(data), 50));
+    }
+
+    @Test
+    public void acceptsWithinLimit() throws IOException {
+        byte[] data = "hello".getBytes(StandardCharsets.UTF_8);
+        assertArrayEquals(data, IOUtils.readFully(new ByteArrayInputStream(data), 16));
+        assertEquals("hello", IOUtils.readFullyAsString(new ByteArrayInputStream(data), StandardCharsets.UTF_8, 16));
+    }
+}

docs/TDLM_CONSUME.md

@@ -0,0 +1,71 @@
+# TDLMPack consume path for TDLM/HMCL
+
+TDLMPack does **not** pull this launcher via Maven, a version pin, or a pack-build download step.
+The pack build publishes the HMCL Server Modpack client (`server-manifest.json` + `overrides/`)
+under the `tdlm-client/latest` layout. Players install the launcher separately.
+
+## After this repo’s publish workflow
+
+Run **Actions → Publish TDLM launcher → Run workflow** with a new `release_tag`.
+
+### Secrets (sibling pattern)
+
+| Name | Where it lives today | Used by |
+|---|---|---|
+| `MAVEN_USER` / `MAVEN_PASSWORD` | **Org** secrets | Stratum / mod Maven publish — **not** used for launcher binaries |
+| `TDLM_PACK_TOKEN` | **TDLMPack repo** secret only (not org) | TDLMPack `pack.yml` Gitea package + release uploads |
+| `github.token` | Actions runtime | HMCL publish fallback when `TDLM_PACK_TOKEN` is unset |
+
+HMCL `publish-tdlm.yml` uses the **same name** as TDLMPack: `secrets.TDLM_PACK_TOKEN`, then falls back to `github.token`.
+Org Maven secrets cannot publish Gitea generic packages / releases.
+
+**Recommended:** promote `TDLM_PACK_TOKEN` to an **org** secret (like `MAVEN_*`) so HMCL inherits it with no new repo secret. Until then, either copy it onto `TDLM/HMCL` or rely on `github.token` (same-repo release usually works; org `tdlm-hmcl` package write may still need the pack token).
+
+### 1. Stable generic URLs (preferred for README / curl / CI)
+
+Overwrite-in-place, same host style as the client fileApi:
+
+```text
+https://git.nest.potatolab.uk:8443/api/packages/TDLM/generic/tdlm-hmcl/latest/HMCL.exe
+https://git.nest.potatolab.uk:8443/api/packages/TDLM/generic/tdlm-hmcl/latest/HMCL.jar
+```
+
+Checksums (when published): `HMCL.exe.sha256`, `HMCL.jar.sha256` next to those names.
+
+### 2. Gitea Release (versioned page)
+
+```text
+https://git.potatolab.uk/TDLM/HMCL/releases/latest
+```
+
+Assets on each tag: `HMCL.exe`, `HMCL.jar`, plus `.sha256` files.
+(Use the nest API host for scripted uploads; public download links on `git.potatolab.uk` are fine for browsers.)
+
+### 3. What TDLMPack should change
+
+In `TDLM/TDLMPack` README §启动, replace the repo-only “安装 TDLM/HMCL” step with one of the URLs above.
+**Do not** add HMCL as a Gradle/Maven dependency of the pack — pack CI stays pack-only.
+
+### 4. Client pack fileApi (CDN)
+
+HMCL default (`Metadata.DEFAULT_CLIENT_FILE_API`):
+
+```text
+https://packages.dandanton.com/tdlm-client/latest
+```
+
+First install / updates fetch `{fileApi}/server-manifest.json` (and `overrides/**` under that root).
+Override at runtime: `-Dhmcl.client.fileApi=…` or jar attribute `hmcl.client.fileApi`.
+
+**TDLMPack must use the same URL** so `server-manifest.json` embeds it:
+
+```text
+TDLM_CLIENT_FILE_API=https://packages.dandanton.com/tdlm-client/latest
+```
+
+Set that as the Gitea Actions **variable** on `TDLM/TDLMPack` (pack.yml already passes `vars.TDLM_CLIENT_FILE_API`).
+
+**Publish caveat:** Pack’s current workflow PUTs the client tree to whatever `TDLM_CLIENT_FILE_API` is (upload root = fileApi). Today that defaults to Gitea generic
+`https://git.nest.potatolab.uk:8443/api/packages/TDLM/generic/tdlm-client/latest`.
+If you only change the HMCL default to the CDN and leave Pack publishing to Gitea, players will 404 unless you **mirror/sync** Gitea → `packages.dandanton.com/tdlm-client/latest`.
+If you set `TDLM_CLIENT_FILE_API` to the CDN URL, Pack CI must be able to PUT to that CDN (or you must split “upload origin” from “public fileApi” in Pack — not implemented today). Do not point HMCL at the CDN without one of those two ops paths.