[9.3.0] Add --incompatible_require_repo_extension_metadata (https://github.com/bazelbuild/bazel/pull/30202)

src/main/java/com/google/devtools/build/lib/bazel/BUILD

@@ -42,6 +42,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/bazel/bzlmod:vendor",
         "//src/main/java/com/google/devtools/build/lib/bazel/commands",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_definition_function",
+        "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_metadata_requirements",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repository_fetch_function",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repository_options",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:utils",

src/main/java/com/google/devtools/build/lib/bazel/BazelRepositoryModule.java

@@ -62,12 +62,14 @@
 import com.google.devtools.build.lib.bazel.commands.ModCommand;
 import com.google.devtools.build.lib.bazel.commands.VendorCommand;
 import com.google.devtools.build.lib.bazel.repository.RepoDefinitionFunction;
+import com.google.devtools.build.lib.bazel.repository.RepoMetadataRequirements;
 import com.google.devtools.build.lib.bazel.repository.RepositoryFetchFunction;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.BazelCompatibilityMode;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.CheckDirectDepsMode;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.LockfileMode;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RepositoryOverride;
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
 import com.google.devtools.build.lib.bazel.repository.RepositoryUtils;
 import com.google.devtools.build.lib.bazel.repository.cache.RepositoryCache;
 import com.google.devtools.build.lib.bazel.repository.downloader.DownloadManager;
@@ -148,6 +150,8 @@ public class BazelRepositoryModule extends BlazeModule {
   private CheckDirectDepsMode checkDirectDepsMode = CheckDirectDepsMode.WARNING;
   private BazelCompatibilityMode bazelCompatibilityMode = BazelCompatibilityMode.ERROR;
   private LockfileMode bazelLockfileMode = LockfileMode.UPDATE;
+  private RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode =
+      RequireRepoExtensionMetadataMode.FALSE;
   private Clock clock;
   private Instant lastRegistryInvalidation = Instant.EPOCH;
 
@@ -294,8 +298,10 @@ public void beforeCommand(CommandEnvironment env) throws AbruptExitException {
     singleExtensionEvalFunction.setDownloadManager(downloadManager);
 
     RepositoryOptions repoOptions = env.getOptions().getOptions(RepositoryOptions.class);
+    requireRepoExtensionMetadataMode = RequireRepoExtensionMetadataMode.FALSE;
     if (repoOptions != null) {
       downloadManager.setDisableDownload(repoOptions.disableDownload);
+      requireRepoExtensionMetadataMode = repoOptions.requireRepoExtensionMetadata;
       if (repoOptions.repositoryDownloaderRetries >= 0) {
         downloadManager.setRetries(repoOptions.repositoryDownloaderRetries);
       }
@@ -760,6 +766,9 @@ public ImmutableList<Injected> getPrecomputedValues() {
             BazelModuleResolutionFunction.CHECK_DIRECT_DEPENDENCIES, checkDirectDepsMode),
         PrecomputedValue.injected(
             BazelModuleResolutionFunction.BAZEL_COMPATIBILITY_MODE, bazelCompatibilityMode),
+        PrecomputedValue.injected(
+            RepoMetadataRequirements.REQUIRE_REPO_EXTENSION_METADATA,
+            requireRepoExtensionMetadataMode),
         PrecomputedValue.injected(BazelLockFileFunction.LOCKFILE_MODE, bazelLockfileMode),
         PrecomputedValue.injected(RepositoryDirectoryValue.IS_VENDOR_COMMAND, false),
         PrecomputedValue.injected(RepositoryDirectoryValue.VENDOR_DIRECTORY, vendorDirectory),

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BUILD

@@ -331,6 +331,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib:runtime",
         "//src/main/java/com/google/devtools/build/lib/analysis:blaze_directories",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_definition",
+        "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_metadata_requirements",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repository_options",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository/downloader",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository/starlark",

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/InnateRunnableExtension.java

@@ -23,6 +23,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.bazel.repository.RepoRule;
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
 import com.google.devtools.build.lib.bazel.repository.starlark.StarlarkRepositoryModule.StarlarkRepoRule;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
@@ -159,7 +160,8 @@ public RunModuleExtensionResult run(
       StarlarkSemantics starlarkSemantics,
       ModuleExtensionId extensionId,
       RepositoryMapping mainRepositoryMapping,
-      Facts facts)
+      Facts facts,
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode)
       throws InterruptedException, ExternalDepsException {
     Object exported = loadedBzl.getModule().getGlobal(ruleName);
     if (exported == null) {

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/RegularRunnableExtension.java

@@ -23,6 +23,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
 import com.google.devtools.build.lib.bazel.repository.downloader.DownloadManager;
 import com.google.devtools.build.lib.bazel.repository.starlark.NeedsSkyframeRestartException;
 import com.google.devtools.build.lib.cmdline.BazelModuleContext;
@@ -223,7 +224,8 @@ public RunModuleExtensionResult run(
       StarlarkSemantics starlarkSemantics,
       ModuleExtensionId extensionId,
       RepositoryMapping mainRepositoryMapping,
-      Facts facts)
+      Facts facts,
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode)
       throws InterruptedException, ExternalDepsException {
     // See below (the `catch CancellationException` clause) for why there's a `while` loop here.
     while (true) {
@@ -239,7 +241,8 @@ public RunModuleExtensionResult run(
                     starlarkSemantics,
                     extensionId,
                     mainRepositoryMapping,
-                    facts));
+                    facts,
+                    requireRepoExtensionMetadataMode));
       } catch (ExecutionException e) {
         Throwables.throwIfInstanceOf(e.getCause(), ExternalDepsException.class);
         Throwables.throwIfInstanceOf(e.getCause(), InterruptedException.class);
@@ -260,7 +263,8 @@ private RunModuleExtensionResult runInternal(
       StarlarkSemantics starlarkSemantics,
       ModuleExtensionId extensionId,
       RepositoryMapping mainRepositoryMapping,
-      Facts facts)
+      Facts facts,
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode)
       throws InterruptedException, ExternalDepsException {
     env.getListener().post(ModuleExtensionEvaluationProgress.ongoing(extensionId, "starting"));
     ModuleExtensionEvalStarlarkThreadContext threadContext =
@@ -301,6 +305,15 @@ private RunModuleExtensionResult runInternal(
         if (returnValue instanceof ModuleExtensionMetadata retMetadata) {
           moduleExtensionMetadata = retMetadata;
         } else {
+          if (shouldRequireMetadata(requireRepoExtensionMetadataMode, extensionId)) {
+            throw ExternalDepsException.withMessage(
+                ExternalDeps.Code.EXTENSION_EVAL_ERROR,
+                "module extension %s did not return extension_metadata (implementation at %s),"
+                    + " but --incompatible_require_repo_extension_metadata=%s requires it",
+                extensionId,
+                extension.implementation().getLocation(),
+                requireRepoExtensionMetadataMode);
+          }
           moduleExtensionMetadata = ModuleExtensionMetadata.DEFAULT;
         }
       } catch (NeedsSkyframeRestartException e) {
@@ -328,6 +341,16 @@ private RunModuleExtensionResult runInternal(
     }
   }
 
+  private static boolean shouldRequireMetadata(
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode,
+      ModuleExtensionId extensionId) {
+    return switch (requireRepoExtensionMetadataMode) {
+      case FALSE -> false;
+      case ALL -> true;
+      case ROOT -> extensionId.bzlFileLabel().getRepository().isMain();
+    };
+  }
+
   private ModuleExtensionContext createContext(
       Environment env,
       SingleExtensionUsagesValue usagesValue,

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/RunnableExtension.java

@@ -17,6 +17,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
 import com.google.devtools.build.lib.cmdline.RepositoryMapping;
 import com.google.devtools.build.lib.rules.repository.RepoRecordedInput;
 import com.google.devtools.build.skyframe.SkyFunction.Environment;
@@ -54,7 +55,8 @@ RunModuleExtensionResult run(
       StarlarkSemantics starlarkSemantics,
       ModuleExtensionId extensionId,
       RepositoryMapping mainRepositoryMapping,
-      Facts facts)
+      Facts facts,
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode)
       throws InterruptedException, ExternalDepsException;
 
   /* Holds the result data from running a module extension */

src/main/java/com/google/devtools/build/lib/bazel/bzlmod/SingleExtensionEvalFunction.java

@@ -16,13 +16,16 @@
 package com.google.devtools.build.lib.bazel.bzlmod;
 
 import static com.google.common.collect.ImmutableBiMap.toImmutableBiMap;
+import static java.util.Objects.requireNonNull;
 import static java.util.stream.Collectors.joining;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.bazel.bzlmod.RunnableExtension.RunModuleExtensionResult;
+import com.google.devtools.build.lib.bazel.repository.RepoMetadataRequirements;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.LockfileMode;
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
 import com.google.devtools.build.lib.bazel.repository.downloader.DownloadManager;
 import com.google.devtools.build.lib.bazel.repository.starlark.NeedsSkyframeRestartException;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
@@ -98,6 +101,8 @@ public SkyValue compute(SkyKey skyKey, Environment env)
     if (starlarkSemantics == null) {
       return null;
     }
+    RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode =
+        requireNonNull(RepoMetadataRequirements.REQUIRE_REPO_EXTENSION_METADATA.get(env));
     RepositoryMappingValue mainRepoMappingValue =
         (RepositoryMappingValue) env.getValue(RepositoryMappingValue.key(RepositoryName.MAIN));
     if (mainRepoMappingValue == null) {
@@ -209,7 +214,8 @@ public SkyValue compute(SkyKey skyKey, Environment env)
               starlarkSemantics,
               extensionId,
               mainRepoMappingValue.repositoryMapping(),
-              lockfileFacts);
+              lockfileFacts,
+              requireRepoExtensionMetadataMode);
     } catch (ExternalDepsException e) {
       throw new SingleExtensionEvalFunctionException(e);
     }

src/main/java/com/google/devtools/build/lib/bazel/repository/BUILD

@@ -39,6 +39,15 @@ java_library(
     ],
 )
 
+java_library(
+    name = "repo_metadata_requirements",
+    srcs = ["RepoMetadataRequirements.java"],
+    deps = [
+        ":repository_options",
+        "//src/main/java/com/google/devtools/build/lib/skyframe:precomputed_value",
+    ],
+)
+
 java_library(
     name = "repository_fetch_function",
     srcs = [
@@ -49,6 +58,8 @@ java_library(
         ":exception",
         ":repo_definition",
         ":repo_definition_value",
+        ":repo_metadata_requirements",
+        ":repository_options",
         ":repository_resolved_event",
         ":utils",
         "//src/main/java/com/google/devtools/build/lib:runtime",

src/main/java/com/google/devtools/build/lib/bazel/repository/RepoMetadataRequirements.java

@@ -0,0 +1,26 @@
+// Copyright 2026 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.bazel.repository;
+
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
+import com.google.devtools.build.lib.skyframe.PrecomputedValue;
+
+/** Skyframe inputs controlling repo and module extension metadata enforcement. */
+public final class RepoMetadataRequirements {
+  public static final PrecomputedValue.Precomputed<RequireRepoExtensionMetadataMode>
+      REQUIRE_REPO_EXTENSION_METADATA =
+          new PrecomputedValue.Precomputed<>("require_repo_extension_metadata");
+
+  private RepoMetadataRequirements() {}
+}

src/main/java/com/google/devtools/build/lib/bazel/repository/RepositoryFetchFunction.java

@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.bazel.bzlmod.NonRegistryOverride;
 import com.google.devtools.build.lib.bazel.bzlmod.VendorFileValue;
 import com.google.devtools.build.lib.bazel.repository.RepositoryFunctionException.AlreadyReportedRepositoryAccessException;
+import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.RequireRepoExtensionMetadataMode;
 import com.google.devtools.build.lib.bazel.repository.cache.LocalRepoContentsCache;
 import com.google.devtools.build.lib.bazel.repository.cache.LocalRepoContentsCache.CandidateRepo;
 import com.google.devtools.build.lib.bazel.repository.downloader.DownloadManager;
@@ -600,6 +601,8 @@ private FetchResult fetch(
     if (env.valuesMissing()) {
       return null;
     }
+    RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode =
+        checkNotNull(RepoMetadataRequirements.REQUIRE_REPO_EXTENSION_METADATA.get(env));
 
     PathPackageLocator packageLocator = PrecomputedValue.PATH_PACKAGE_LOCATOR.get(env);
     if (env.valuesMissing()) {
@@ -683,7 +686,13 @@ private FetchResult fetch(
                     RepoMetadata.Reproducibility.NO,
                     Dict.cast(dict, String.class, Object.class, "return value"));
             case RepoMetadata rm -> rm;
-            default -> RepoMetadata.NONREPRODUCIBLE;
+            default -> {
+              if (shouldRequireRepoMetadata(requireRepoExtensionMetadataMode, repoDefinition)) {
+                throwDefaultRepoMetadataError(
+                    repoDefinition, requireRepoExtensionMetadataMode, env);
+              }
+              yield RepoMetadata.NONREPRODUCIBLE;
+            }
           };
       RepositoryResolvedEvent resolved =
           new RepositoryResolvedEvent(repoDefinition, repoMetadata.attrsForReproducibility());
@@ -743,6 +752,37 @@ private FetchResult fetch(
     return new FetchResult(recordedInputValues, repoMetadata.reproducible());
   }
 
+  private static boolean shouldRequireRepoMetadata(
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode,
+      RepoDefinition repoDefinition) {
+    return switch (requireRepoExtensionMetadataMode) {
+      case FALSE -> false;
+      case ALL -> true;
+      case ROOT -> repoDefinition.repoRule().id().bzlFileLabel().getRepository().isMain();
+    };
+  }
+
+  private static void throwDefaultRepoMetadataError(
+      RepoDefinition repoDefinition,
+      RequireRepoExtensionMetadataMode requireRepoExtensionMetadataMode,
+      Environment env)
+      throws RepositoryFunctionException {
+    String definitionInformation =
+        RepositoryResolvedEvent.getRuleDefinitionInformation(repoDefinition);
+    String message =
+        ("repository rule for repo '%s' did not return repo_metadata (implementation at %s), but"
+                + " --incompatible_require_repo_extension_metadata=%s requires it")
+            .formatted(
+                repoDefinition.name(),
+                repoDefinition.repoRule().impl().getLocation(),
+                requireRepoExtensionMetadataMode);
+    env.getListener().handle(Event.error(message));
+    env.getListener().handle(Event.info(definitionInformation));
+    throw new RepositoryFunctionException(
+        new AlreadyReportedRepositoryAccessException(new IOException(message)),
+        Transience.PERSISTENT);
+  }
+
   @Nullable
   private RepositoryDirectoryValue setupOverride(
       PathFragment sourcePath, Environment env, Path repoRoot, RepositoryName repoName)

src/main/java/com/google/devtools/build/lib/bazel/repository/RepositoryOptions.java

@@ -18,6 +18,7 @@
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.util.OptionsUtils;
 import com.google.devtools.build.lib.vfs.PathFragment;
+import com.google.devtools.common.options.BoolOrEnumConverter;
 import com.google.devtools.common.options.Converter;
 import com.google.devtools.common.options.Converters;
 import com.google.devtools.common.options.Converters.DurationConverter;
@@ -341,6 +342,20 @@ verified by hashes stored in the registry (and thus pinned by the lockfile).
               + " warning when mismatch detected.")
   public BazelCompatibilityMode bazelCompatibilityMode;
 
+  @Option(
+      name = "incompatible_require_repo_extension_metadata",
+      defaultValue = "false",
+      converter = RequireRepoExtensionMetadataMode.Converter.class,
+      documentationCategory = OptionDocumentationCategory.BZLMOD,
+      effectTags = {OptionEffectTag.LOADING_AND_ANALYSIS},
+      metadataTags = {OptionMetadataTag.INCOMPATIBLE_CHANGE},
+      help =
+          "Require repository rules and module extensions to return explicit metadata. Valid values"
+              + " are `false` to disable the check, `all` to require metadata everywhere, or `root`"
+              + " to require metadata only for repo rules and extensions defined in the root"
+              + " module.")
+  public RequireRepoExtensionMetadataMode requireRepoExtensionMetadata;
+
   @Option(
       name = "lockfile_mode",
       converter = LockfileMode.Converter.class,
@@ -397,6 +412,33 @@ public Converter() {
     }
   }
 
+  /** An enum for specifying when repo and extension metadata is required. */
+  public enum RequireRepoExtensionMetadataMode {
+    FALSE, // Don't require metadata.
+    ALL, // Require metadata everywhere.
+    ROOT; // Require metadata for repo rules and extensions defined in the root module.
+
+    @Override
+    public String toString() {
+      return switch (this) {
+        case FALSE -> "false";
+        case ALL -> "all";
+        case ROOT -> "root";
+      };
+    }
+
+    /** Converts to {@link RequireRepoExtensionMetadataMode}. */
+    public static class Converter extends BoolOrEnumConverter<RequireRepoExtensionMetadataMode> {
+      public Converter() {
+        super(
+            RequireRepoExtensionMetadataMode.class,
+            "repo extension metadata mode",
+            RequireRepoExtensionMetadataMode.ALL,
+            RequireRepoExtensionMetadataMode.FALSE);
+      }
+    }
+  }
+
   /** An enum for specifying how to use the lockfile. */
   public enum LockfileMode {
     OFF, // Don't use the lockfile at all.

src/main/java/com/google/devtools/build/lib/skyframe/packages/BUILD

@@ -91,6 +91,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/bazel/bzlmod:resolution_impl",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_definition_function",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_definition_value",
+        "//src/main/java/com/google/devtools/build/lib/bazel/repository:repo_metadata_requirements",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repository_fetch_function",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository:repository_options",
         "//src/main/java/com/google/devtools/build/lib/bazel/repository/cache",