Ignore jar files in the mods folder that are not Forge mods. Closes #9968

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/AbstractModProvider.java

@@ -18,6 +18,7 @@ import net.minecraftforge.forgespi.locating.IModProvider;
 import net.minecraftforge.forgespi.locating.ModFileLoadingException;
 
 import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 
 import java.io.IOException;
@@ -36,6 +37,11 @@ public abstract class AbstractModProvider implements IModProvider {
     protected static final String MODS_TOML = "META-INF/mods.toml";
 
     protected IModLocator.ModFileOrException createMod(Path path) {
+        return createMod(path, false);
+    }
+
+    @Nullable
+    protected IModLocator.ModFileOrException createMod(Path path, boolean ignoreUnknown) {
         var mjm = new ModJarMetadata();
         var sj = SecureJar.from(
             jar -> jar.moduleDataProvider().findFile(MODS_TOML).isPresent() ? mjm : JarMetadata.from(jar, path),
@@ -57,6 +63,8 @@ public abstract class AbstractModProvider implements IModProvider {
         } else if (type != null) {
             LOGGER.debug(LogMarkers.SCAN, "Found {} mod of type {}: {}", JarFile.MANIFEST_NAME, type, path);
             mod = new ModFile(sj, this, this::manifestParser, type);
+        } else if (ignoreUnknown) {
+            return null;
         } else
             return new IModLocator.ModFileOrException(null, new ModFileLoadingException("Invalid mod file found " + path));
 

fmlloader/src/main/java/net/minecraftforge/fml/loading/moddiscovery/ModsFolderLocator.java

@@ -16,6 +16,7 @@ import org.slf4j.Logger;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
@@ -42,11 +43,21 @@ public class ModsFolderLocator extends AbstractModProvider implements IModLocato
     public List<IModLocator.ModFileOrException> scanMods() {
         LOGGER.debug(LogMarkers.SCAN, "Scanning mods dir {} for mods", this.modFolder);
         var excluded = ModDirTransformerDiscoverer.allExcluded();
-        try (var stream = Files.list(this.modFolder)) {
-            return stream.filter(path -> !excluded.contains(path) && path.getFileName().toString().toLowerCase(Locale.ROOT).endsWith(SUFFIX))
-                .sorted(Comparator.comparing(path -> path.getFileName().toString().toLowerCase(Locale.ROOT)))
-                .map(this::createMod)
-                .toList();
+        try {
+            var ret = new ArrayList<IModLocator.ModFileOrException>();
+            var files = Files.list(this.modFolder).toList();
+            for (var file : files) {
+                var name = file.getFileName().toString().toLowerCase(Locale.ROOT);
+                if (excluded.contains(file) || !name.endsWith(SUFFIX))
+                    continue;
+                var mod = this.createMod(file, true);
+                if (mod == null) {
+                    LOGGER.debug(LogMarkers.SCAN, "Found unknown jar file {} ignoring", file);
+                } else {
+                    ret.add(mod);
+                }
+            }
+            return ret;
         } catch (IOException e) {
             return sneak(e);
         }