Add option to completely hide a crash-callable depending on a runtime value (#9372)

fmlcore/src/main/java/net/minecraftforge/fml/CrashReportCallables.java

@@ -5,33 +5,93 @@
 
 package net.minecraftforge.fml;
 
+import com.mojang.logging.LogUtils;
+import org.slf4j.Logger;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.BooleanSupplier;
 import java.util.function.Supplier;
 
-public class CrashReportCallables {
+public class CrashReportCallables
+{
+    private static final Logger LOGGER = LogUtils.getLogger();
     private static final List<ISystemReportExtender> crashCallables = Collections.synchronizedList(new ArrayList<>());
 
+    /**
+     * Register a custom {@link ISystemReportExtender}
+     */
     public static void registerCrashCallable(ISystemReportExtender callable)
     {
         crashCallables.add(callable);
     }
 
-    public static void registerCrashCallable(String headerName, Supplier<String> reportGenerator) {
-        registerCrashCallable(new ISystemReportExtender() {
+    /**
+     * Register a {@link ISystemReportExtender system report extender} with the given header name and content
+     * generator, which will always be appended to the system report
+     * @param headerName The name of the system report entry
+     * @param reportGenerator The report generator to be called when a crash report is built
+     */
+    public static void registerCrashCallable(String headerName, Supplier<String> reportGenerator)
+    {
+        registerCrashCallable(new ISystemReportExtender()
+        {
             @Override
-            public String getLabel() {
+            public String getLabel()
+            {
                 return headerName;
             }
+
             @Override
-            public String get() {
+            public String get()
+            {
                 return reportGenerator.get();
             }
         });
     }
 
-    public static List<ISystemReportExtender> allCrashCallables() {
+    /**
+     * Register a {@link ISystemReportExtender system report extender} with the given header name and content
+     * generator, which will only be appended to the system report when the given {@link BooleanSupplier} returns true
+     * @param headerName The name of the system report entry
+     * @param reportGenerator The report generator to be called when a crash report is built
+     * @param active The supplier of the flag to be checked when a crash report is built
+     */
+    public static void registerCrashCallable(String headerName, Supplier<String> reportGenerator, BooleanSupplier active)
+    {
+        registerCrashCallable(new ISystemReportExtender()
+        {
+            @Override
+            public String getLabel()
+            {
+                return headerName;
+            }
+
+            @Override
+            public String get()
+            {
+                return reportGenerator.get();
+            }
+
+            @Override
+            public boolean isActive()
+            {
+                try
+                {
+                    return active.getAsBoolean();
+                }
+                catch (Throwable t)
+                {
+                    LOGGER.warn("CrashCallable '{}' threw an exception while checking the active flag, disabling", headerName, t);
+                    return false;
+                }
+            }
+        });
+    }
+
+    public static List<ISystemReportExtender> allCrashCallables()
+    {
         return List.copyOf(crashCallables);
     }
 }

fmlcore/src/main/java/net/minecraftforge/fml/ISystemReportExtender.java

@@ -10,4 +10,9 @@ import java.util.function.Supplier;
 public interface ISystemReportExtender extends Supplier<String>
 {
     String getLabel();
+
+    default boolean isActive()
+    {
+        return true;
+    }
 }

src/main/java/net/minecraftforge/logging/CrashReportExtender.java

@@ -26,9 +26,12 @@ public class CrashReportExtender
 
     public static void extendSystemReport(final SystemReport systemReport)
     {
-        for (final ISystemReportExtender call: CrashReportCallables.allCrashCallables())
+        for (final ISystemReportExtender call : CrashReportCallables.allCrashCallables())
         {
-            systemReport.setDetail(call.getLabel(), call);
+            if (call.isActive())
+            {
+                systemReport.setDetail(call.getLabel(), call);
+            }
         }
     }
 

src/test/java/net/minecraftforge/debug/CrashCallableTest.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.debug;
+
+import net.minecraftforge.fml.CrashReportCallables;
+import net.minecraftforge.fml.common.Mod;
+
+/**
+ * Test features and guards of crash-callables.
+ * <ul>
+ * <li>The "AlwaysActiveCrashCallable" must always be printed to the crash report</li>
+ * <li>The "ToggleableCrashCallable" must only be printed to the crash report when the {@code ENABLED} flag is {@code true}</li>
+ * <li>The "BadContentCrashCallable" must always print "BadContentCrashCallable: ERR" to the crash report and
+ * print an exception to the log (relies on a try-catch in vanilla code)</li>
+ * <li>The "BadFlagCrashCallable" must never print to the crash report and must print an exception to the log</li>
+ * </ul>
+ * To initiate a debug crash to test this, hold F3 + C for 10 seconds.
+ */
+@Mod("crash_callable_test")
+public class CrashCallableTest
+{
+    private static final boolean ENABLED = true;
+
+    public CrashCallableTest()
+    {
+        CrashReportCallables.registerCrashCallable("AlwaysActiveCrashCallable", () -> "test");
+        CrashReportCallables.registerCrashCallable("ToggleableCrashCallable", () -> "active", () -> ENABLED);
+        CrashReportCallables.registerCrashCallable("BadContentCrashCallable", () ->
+        {
+            throw new UnsupportedOperationException();
+        });
+        CrashReportCallables.registerCrashCallable("BadFlagCrashCallable", () -> "why am I here?!", () ->
+        {
+            throw new UnsupportedOperationException();
+        });
+    }
+}

src/test/resources/META-INF/mods.toml

@@ -21,6 +21,8 @@ license="LGPL v2.1"
     modId="advancement_event_test"
 [[mods]]
     modId="shader_resources_test"
+[[mods]]
+    modId="crash_callable_test"
 
 # LEGACY TEST CASES
 ###### The mods below are from the old test framework and need to be yeeted later again.