[Android] Add --mnemonic_cache_salt flag for Bazel 8.1.1

src/main/java/com/google/devtools/build/lib/actions/ActionCacheChecker.java

@@ -559,7 +559,8 @@ public Token getTokenIfNeedToExecute(
       OutputMetadataStore outputMetadataStore,
       ArtifactExpander artifactExpander,
       Map<String, String> remoteDefaultPlatformProperties,
-      @Nullable RemoteArtifactChecker remoteArtifactChecker)
+      @Nullable RemoteArtifactChecker remoteArtifactChecker,
+      ImmutableMap<String, String> mnemonicCacheSalts)
       throws InterruptedException {
     // TODO(bazel-team): (2010) For RunfilesAction/SymlinkAction and similar actions that
     // produce only symlinks we should not check whether inputs are valid at all - all that matters
@@ -618,7 +619,8 @@ public Token getTokenIfNeedToExecute(
         outputPermissions,
         remoteDefaultPlatformProperties,
         cachedOutputMetadata,
-        remoteArtifactChecker)) {
+        remoteArtifactChecker,
+        mnemonicCacheSalts.get(action.getMnemonic()))) {
       if (entry != null) {
         removeCacheEntry(action);
       }
@@ -638,6 +640,34 @@ public Token getTokenIfNeedToExecute(
     return null;
   }
 
+  /** Backward-compat overload for callers that don't pass mnemonicCacheSalts. */
+  @Nullable
+  public Token getTokenIfNeedToExecute(
+      Action action,
+      List<Artifact> resolvedCacheArtifacts,
+      Map<String, String> clientEnv,
+      OutputPermissions outputPermissions,
+      EventHandler handler,
+      InputMetadataProvider inputMetadataProvider,
+      OutputMetadataStore outputMetadataStore,
+      ArtifactExpander artifactExpander,
+      Map<String, String> remoteDefaultPlatformProperties,
+      @Nullable RemoteArtifactChecker remoteArtifactChecker)
+      throws InterruptedException {
+    return getTokenIfNeedToExecute(
+        action,
+        resolvedCacheArtifacts,
+        clientEnv,
+        outputPermissions,
+        handler,
+        inputMetadataProvider,
+        outputMetadataStore,
+        artifactExpander,
+        remoteDefaultPlatformProperties,
+        remoteArtifactChecker,
+        ImmutableMap.of());
+  }
+
   private boolean mustExecute(
       Action action,
       @Nullable ActionCache.Entry entry,
@@ -651,7 +681,8 @@ private boolean mustExecute(
       OutputPermissions outputPermissions,
       Map<String, String> remoteDefaultPlatformProperties,
       @Nullable CachedOutputMetadata cachedOutputMetadata,
-      @Nullable RemoteArtifactChecker remoteArtifactChecker)
+      @Nullable RemoteArtifactChecker remoteArtifactChecker,
+      @Nullable String mnemonicSalt)
       throws InterruptedException {
     // Unconditional execution can be applied only for actions that are allowed to be executed.
     if (unconditionalExecution(action)) {
@@ -696,7 +727,7 @@ private boolean mustExecute(
 
     Map<String, String> usedEnvironment =
         computeUsedEnv(action, clientEnv, remoteDefaultPlatformProperties);
-    if (!entry.sameActionProperties(usedEnvironment, outputPermissions)) {
+    if (!entry.sameActionProperties(usedEnvironment, outputPermissions, mnemonicSalt)) {
       reportClientEnv(handler, action, usedEnvironment);
       actionCache.accountMiss(MissReason.DIFFERENT_ENVIRONMENT);
       return true;
@@ -771,7 +802,8 @@ public void updateActionCache(
       Map<String, String> clientEnv,
       OutputPermissions outputPermissions,
       Map<String, String> remoteDefaultPlatformProperties,
-      boolean isDelayedUpdate)
+      boolean isDelayedUpdate,
+      ImmutableMap<String, String> mnemonicCacheSalts)
       throws IOException, InterruptedException {
     checkState(cacheConfig.enabled(), "cache unexpectedly disabled, action: %s", action);
     Preconditions.checkArgument(token != null, "token unexpectedly null, action: %s", action);
@@ -797,7 +829,8 @@ public void updateActionCache(
 
     ActionCache.Entry entry =
         new ActionCache.Entry(
-            actionKey, usedEnvironment, action.discoversInputs(), outputPermissions);
+            actionKey, usedEnvironment, action.discoversInputs(), outputPermissions,
+            mnemonicCacheSalts.get(action.getMnemonic()));
     for (Artifact output : action.getOutputs()) {
       // Remove old records from the cache if they used different key.
       String execPath = output.getExecPathString();
@@ -864,7 +897,8 @@ public void updateActionCache(
                 clientEnv,
                 outputPermissions,
                 remoteDefaultPlatformProperties,
-                true /* isDelayedUpdate */
+                true /* isDelayedUpdate */,
+                mnemonicCacheSalts
         );
       }
     }
@@ -881,6 +915,55 @@ public void updateActionCache(
     }
   }
 
+  /** Backward-compat overload for callers that don't pass mnemonicCacheSalts. */
+  public void updateActionCache(
+      Action action,
+      Token token,
+      InputMetadataProvider inputMetadataProvider,
+      OutputMetadataStore outputMetadataStore,
+      ArtifactExpander artifactExpander,
+      Map<String, String> clientEnv,
+      OutputPermissions outputPermissions,
+      Map<String, String> remoteDefaultPlatformProperties,
+      boolean isDelayedUpdate)
+      throws IOException, InterruptedException {
+    updateActionCache(
+        action,
+        token,
+        inputMetadataProvider,
+        outputMetadataStore,
+        artifactExpander,
+        clientEnv,
+        outputPermissions,
+        remoteDefaultPlatformProperties,
+        isDelayedUpdate,
+        ImmutableMap.of());
+  }
+
+  /** Backward-compat overload for callers that don't pass isDelayedUpdate or mnemonicCacheSalts. */
+  public void updateActionCache(
+      Action action,
+      Token token,
+      InputMetadataProvider inputMetadataProvider,
+      OutputMetadataStore outputMetadataStore,
+      ArtifactExpander artifactExpander,
+      Map<String, String> clientEnv,
+      OutputPermissions outputPermissions,
+      Map<String, String> remoteDefaultPlatformProperties)
+      throws IOException, InterruptedException {
+    updateActionCache(
+        action,
+        token,
+        inputMetadataProvider,
+        outputMetadataStore,
+        artifactExpander,
+        clientEnv,
+        outputPermissions,
+        remoteDefaultPlatformProperties,
+        /* isDelayedUpdate= */ false,
+        ImmutableMap.of());
+  }
+
   @Nullable
   public List<Artifact> getCachedInputs(Action action, PackageRootResolver resolver)
       throws PackageRootResolver.PackageRootException, InterruptedException {

src/main/java/com/google/devtools/build/lib/actions/cache/ActionCache.java

@@ -176,8 +176,17 @@ public Entry(
         Map<String, String> usedClientEnv,
         boolean discoversInputs,
         OutputPermissions outputPermissions) {
+      this(key, usedClientEnv, discoversInputs, outputPermissions, null);
+    }
+
+    public Entry(
+        String key,
+        Map<String, String> usedClientEnv,
+        boolean discoversInputs,
+        OutputPermissions outputPermissions,
+        @Nullable String mnemonicSalt) {
       actionKey = key;
-      this.actionPropertiesDigest = digestActionProperties(usedClientEnv, outputPermissions);
+      this.actionPropertiesDigest = digestActionProperties(usedClientEnv, outputPermissions, mnemonicSalt);
       files = discoversInputs ? new ArrayList<>() : null;
       mdMap = new HashMap<>();
       outputFileMetadata = new HashMap<>();
@@ -206,6 +215,11 @@ public Entry(
      */
     private static byte[] digestActionProperties(
         Map<String, String> clientEnv, OutputPermissions outputPermissions) {
+      return digestActionProperties(clientEnv, outputPermissions, null);
+    }
+
+    private static byte[] digestActionProperties(
+        Map<String, String> clientEnv, OutputPermissions outputPermissions, @Nullable String mnemonicSalt) {
       byte[] result = EMPTY_CLIENT_ENV_DIGEST;
       Fingerprint fp = new Fingerprint();
       for (Map.Entry<String, String> entry : clientEnv.entrySet()) {
@@ -220,6 +234,10 @@ private static byte[] digestActionProperties(
         fp.addInt(outputPermissions.getPermissionsMode());
         result = DigestUtils.combineUnordered(result, fp.digestAndReset());
       }
+      if (mnemonicSalt != null) {
+        fp.addString(mnemonicSalt);
+        result = DigestUtils.xor(result, fp.digestAndReset());
+      }
       return result;
     }
 
@@ -323,9 +341,9 @@ public byte[] getActionPropertiesDigest() {
 
     /** Determines whether this entry has the same action properties as the one given. */
     public boolean sameActionProperties(
-        Map<String, String> clientEnv, OutputPermissions outputPermissions) {
+        Map<String, String> clientEnv, OutputPermissions outputPermissions, @Nullable String mnemonicSalt) {
       return Arrays.equals(
-          digestActionProperties(clientEnv, outputPermissions), actionPropertiesDigest);
+          digestActionProperties(clientEnv, outputPermissions, mnemonicSalt), actionPropertiesDigest);
     }
 
     /**

src/main/java/com/google/devtools/build/lib/buildtool/ExecutionTool.java

@@ -340,8 +340,11 @@ void prepareForExecution(Stopwatch executionTimer)
         remoteArtifactChecker,
         buildRequestOptions.fsvcThreads);
     try (SilentCloseable c = Profiler.instance().profile("configureActionExecutor")) {
+      ExecutionOptions executionOptions = request.getOptions(ExecutionOptions.class);
       skyframeExecutor.configureActionExecutor(
-          skyframeBuilder.getFileCache(), skyframeBuilder.getActionInputPrefetcher());
+          skyframeBuilder.getFileCache(),
+          skyframeBuilder.getActionInputPrefetcher(),
+          executionOptions != null ? executionOptions.getMnemonicCacheSalts() : ImmutableMap.of());
     }
 
     skyframeExecutor.deleteActionsIfRemoteOptionsChanged(request);
@@ -953,6 +956,9 @@ private Builder createBuilder(
       ModifiedFileSet modifiedOutputFiles,
       boolean shouldStoreRemoteOutputMetadataInActionCache) {
     BuildRequestOptions options = request.getBuildOptions();
+    ExecutionOptions executionOptions = request.getOptions(ExecutionOptions.class);
+    ImmutableMap<String, String> mnemonicCacheSalts =
+        executionOptions != null ? executionOptions.getMnemonicCacheSalts() : ImmutableMap.of();
 
     skyframeExecutor.setActionOutputRoot(env.getActionTempsDirectory());
 
@@ -986,7 +992,8 @@ private Builder createBuilder(
         env.getFileCache(),
         prefetcher,
         env.getOutputDirectoryHelper(),
-        env.getRuntime().getBugReporter());
+        env.getRuntime().getBugReporter(),
+        mnemonicCacheSalts);
   }
 
   @VisibleForTesting

src/main/java/com/google/devtools/build/lib/buildtool/SkyframeBuilder.java

@@ -18,6 +18,7 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Range;
 import com.google.common.collect.Sets;
@@ -72,6 +73,7 @@ public class SkyframeBuilder implements Builder {
   private final ActionOutputDirectoryHelper actionOutputDirectoryHelper;
   private final ActionCacheChecker actionCacheChecker;
   private final BugReporter bugReporter;
+  private final ImmutableMap<String, String> mnemonicCacheSalts;
 
   @VisibleForTesting
   public SkyframeBuilder(
@@ -83,6 +85,28 @@ public SkyframeBuilder(
       ActionInputPrefetcher actionInputPrefetcher,
       ActionOutputDirectoryHelper actionOutputDirectoryHelper,
       BugReporter bugReporter) {
+    this(
+        skyframeExecutor,
+        resourceManager,
+        actionCacheChecker,
+        modifiedOutputFiles,
+        fileCache,
+        actionInputPrefetcher,
+        actionOutputDirectoryHelper,
+        bugReporter,
+        ImmutableMap.of());
+  }
+
+  public SkyframeBuilder(
+      SkyframeExecutor skyframeExecutor,
+      ResourceManager resourceManager,
+      ActionCacheChecker actionCacheChecker,
+      ModifiedFileSet modifiedOutputFiles,
+      InputMetadataProvider fileCache,
+      ActionInputPrefetcher actionInputPrefetcher,
+      ActionOutputDirectoryHelper actionOutputDirectoryHelper,
+      BugReporter bugReporter,
+      ImmutableMap<String, String> mnemonicCacheSalts) {
     this.resourceManager = resourceManager;
     this.skyframeExecutor = skyframeExecutor;
     this.actionCacheChecker = actionCacheChecker;
@@ -91,6 +115,7 @@ public SkyframeBuilder(
     this.actionInputPrefetcher = actionInputPrefetcher;
     this.actionOutputDirectoryHelper = actionOutputDirectoryHelper;
     this.bugReporter = bugReporter;
+    this.mnemonicCacheSalts = mnemonicCacheSalts;
   }
 
   @Override
@@ -115,7 +140,7 @@ public void buildArtifacts(
     skyframeExecutor.detectModifiedOutputFiles(
         modifiedOutputFiles, lastExecutionTimeRange, remoteArtifactChecker, fsvcThreads);
     try (SilentCloseable c = Profiler.instance().profile("configureActionExecutor")) {
-      skyframeExecutor.configureActionExecutor(fileCache, actionInputPrefetcher);
+      skyframeExecutor.configureActionExecutor(fileCache, actionInputPrefetcher, mnemonicCacheSalts);
     }
     // Note that executionProgressReceiver accesses builtTargets concurrently (after wrapping in a
     // synchronized collection), so unsynchronized access to this variable is unsafe while it runs.

src/main/java/com/google/devtools/build/lib/exec/ExecutionOptions.java

@@ -13,6 +13,7 @@
 // limitations under the License.
 package com.google.devtools.build.lib.exec;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.ActionExecutionContext;
 import com.google.devtools.build.lib.actions.ActionExecutionContext.ShowSubcommands;
@@ -562,6 +563,36 @@ public boolean usingLocalTestJobs() {
               + " code 39.")
   public int remoteRetryOnTransientCacheError;
 
+  @Option(
+      name = "mnemonic_cache_salt",
+      allowMultiple = true,
+      converter = Converters.AssignmentConverter.class,
+      defaultValue = "null",
+      documentationCategory = OptionDocumentationCategory.EXECUTION_STRATEGY,
+      effectTags = {OptionEffectTag.EXECUTION, OptionEffectTag.ACTION_COMMAND_LINES},
+      help =
+          "Specify a salt value to include in the cache key for actions with a given mnemonic. "
+              + "Format: --mnemonic_cache_salt=Mnemonic=salt. "
+              + "This invalidates both local and remote cache entries for that mnemonic. "
+              + "Example: --mnemonic_cache_salt=Javac=V2 --mnemonic_cache_salt=KotlinCompile=V3")
+  public List<Map.Entry<String, String>> mnemonicCacheSalts;
+
+  /**
+   * Returns the mnemonic cache salts as an immutable map.
+   *
+   * <p>If the same mnemonic is specified multiple times, the last value wins.
+   */
+  public ImmutableMap<String, String> getMnemonicCacheSalts() {
+    if (mnemonicCacheSalts == null || mnemonicCacheSalts.isEmpty()) {
+      return ImmutableMap.of();
+    }
+    ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
+    for (Map.Entry<String, String> entry : mnemonicCacheSalts) {
+      builder.put(entry.getKey(), entry.getValue());
+    }
+    return builder.buildKeepingLast();
+  }
+
   /** An enum for specifying different formats of test output. */
   public enum TestOutputFormat {
     SUMMARY, // Provide summary output only.

src/main/java/com/google/devtools/build/lib/remote/RemoteActionContextProvider.java

@@ -191,6 +191,12 @@ private RemoteExecutionService getRemoteExecutionService() {
               outputService,
               knownMissingCasDigests);
       env.getEventBus().register(remoteExecutionService);
+      ExecutionOptions remoteExecExecutionOptions =
+          env.getOptions().getOptions(ExecutionOptions.class);
+      if (remoteExecExecutionOptions != null) {
+        remoteExecutionService.setMnemonicCacheSalts(
+            remoteExecExecutionOptions.getMnemonicCacheSalts());
+      }
     }
 
     return remoteExecutionService;