Watch arbitrary file in repo rules

* Starlark API changes
  * New method `rctx.watch()` that watches a path. As of right now, said path must exist and be a regular file, but that will change in follow-ups.
  * Existing method `rctx.read()` gets a new optional boolean parameter `watch` that defaults to True. This causes the file read to be watched as well by default, even if it's not addressed by a label.
  * Both changes apply to `mctx` as well.
* Marker file format changes
  * `FILE:` marker file entries can now be `FILE:` followed by either an absolute path (starts with a singular '/'), or a label-like ... thing (which is a label but has a slash in place of a colon). This is because we might be watching something inside a repo that is _not_ under a package.
  * Same change will happen to the `accumulatedFileDigests` sections of the module lockfile.
* Code changes
  * `RepoRecordedInput.File` subclasses are renamed to `FileOutsideWorkspace` (absolute paths) and `FileInsideWorkspace` (label-like things) instead to better reflect their meaning.
  * Unified the file watching/digest checking logic in SingleExtensionEvalFunction with the RepoRecordedInput stuff. Follow-ups will unify more.
  * Moved RepoRecordedInput to its own BUILD target as it's being used outside the repo fetching machinery (namely, module extensions)
  * Since `FileOutsideWorkspace` has to be an absolute path (never relative), we don't need a "base directory" for the RepoRecordedInput parser. What we really need is just the FileSystem object. Refactored code to reflect that.

RELNOTES: Added a new method, `repository_ctx.watch()`, which asks Bazel to watch for changes to an arbitrary file. When said file changes, Bazel will refetch the repo.

Work towards #20952.

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

@@ -257,7 +257,7 @@ public void workspaceInit(
             new ModuleFileFunction(registryFactory, directories.getWorkspace(), builtinModules))
         .addSkyFunction(SkyFunctions.BAZEL_DEP_GRAPH, new BazelDepGraphFunction())
         .addSkyFunction(
-            SkyFunctions.BAZEL_LOCK_FILE, new BazelLockFileFunction(directories.getWorkspace()))
+            SkyFunctions.BAZEL_LOCK_FILE, new BazelLockFileFunction(directories.getWorkspace(), runtime.getFileSystem()))
         .addSkyFunction(SkyFunctions.BAZEL_FETCH_ALL, new BazelFetchAllFunction())
         .addSkyFunction(SkyFunctions.BAZEL_MOD_TIDY, new BazelModTidyFunction())
         .addSkyFunction(SkyFunctions.BAZEL_MODULE_INSPECTION, new BazelModuleInspectorFunction())

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

@@ -155,6 +155,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/events",
         "//src/main/java/com/google/devtools/build/lib/packages",
+        "//src/main/java/com/google/devtools/build/lib/rules:repository/repo_recorded_input",
         "//src/main/java/com/google/devtools/build/lib/skyframe:sky_functions",
         "//src/main/java/com/google/devtools/build/lib/skyframe/serialization:visible-for-serialization",
         "//src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec",
@@ -217,6 +218,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/events",
         "//src/main/java/com/google/devtools/build/lib/packages",
         "//src/main/java/com/google/devtools/build/lib/profiler",
+        "//src/main/java/com/google/devtools/build/lib/rules:repository/repo_recorded_input",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_directory_value",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_function",
         "//src/main/java/com/google/devtools/build/lib/skyframe:bzl_load_failed_exception",

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

@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.profiler.SilentCloseable;
 import com.google.devtools.build.lib.server.FailureDetails.ExternalDeps.Code;
 import com.google.devtools.build.lib.skyframe.PrecomputedValue.Precomputed;
+import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Root;
@@ -52,6 +53,7 @@ public class BazelLockFileFunction implements SkyFunction {
       Pattern.compile("\"lockFileVersion\":\\s*(\\d+)");
 
   private final Path rootDirectory;
+  private final FileSystem runtimeFileSystem;
 
   private static final BzlmodFlagsAndEnvVars EMPTY_FLAGS =
       BzlmodFlagsAndEnvVars.create(
@@ -67,8 +69,9 @@ public class BazelLockFileFunction implements SkyFunction {
           .setModuleExtensions(ImmutableMap.of())
           .build();
 
-  public BazelLockFileFunction(Path rootDirectory) {
+  public BazelLockFileFunction(Path rootDirectory, FileSystem runtimeFileSystem) {
     this.rootDirectory = rootDirectory;
+    this.runtimeFileSystem = runtimeFileSystem;
   }
 
   @Override
@@ -84,7 +87,7 @@ public SkyValue compute(SkyKey skyKey, Environment env)
     }
 
     try (SilentCloseable c = Profiler.instance().profile(ProfilerTask.BZLMOD, "parse lockfile")) {
-      return getLockfileValue(lockfilePath, rootDirectory);
+      return getLockfileValue(lockfilePath, rootDirectory, runtimeFileSystem);
     } catch (IOException | JsonSyntaxException | NullPointerException e) {
       throw new BazelLockfileFunctionException(
           ExternalDepsException.withMessage(
@@ -96,7 +99,8 @@ public SkyValue compute(SkyKey skyKey, Environment env)
     }
   }
 
-  public static BazelLockFileValue getLockfileValue(RootedPath lockfilePath, Path rootDirectory)
+  public static BazelLockFileValue getLockfileValue(
+      RootedPath lockfilePath, Path rootDirectory, FileSystem runtimeFileSystem)
       throws IOException {
     BazelLockFileValue bazelLockFileValue;
     try {
@@ -110,7 +114,8 @@ public static BazelLockFileValue getLockfileValue(RootedPath lockfilePath, Path
                         .asPath()
                         .getParentDirectory()
                         .getRelative(LabelConstants.MODULE_DOT_BAZEL_FILE_NAME),
-                    rootDirectory)
+                    rootDirectory,
+                    runtimeFileSystem)
                 .fromJson(json, BazelLockFileValue.class);
       } else {
         // This is an old version, needs to be updated

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

@@ -28,6 +28,7 @@
 import com.google.devtools.build.lib.runtime.BlazeModule;
 import com.google.devtools.build.lib.runtime.CommandEnvironment;
 import com.google.devtools.build.lib.util.AbruptExitException;
+import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.Root;
@@ -47,6 +48,7 @@ public class BazelLockFileModule extends BlazeModule {
   @Nullable private BazelModuleResolutionEvent moduleResolutionEvent;
   private final Map<ModuleExtensionId, ModuleExtensionResolutionEvent>
       extensionResolutionEventsMap = new HashMap<>();
+  private FileSystem runtimeFileSystem;
 
   private static final GoogleLogger logger = GoogleLogger.forEnclosingClass();
 
@@ -57,6 +59,7 @@ public void beforeCommand(CommandEnvironment env) {
     if (options.lockfileMode.equals(LockfileMode.UPDATE)) {
       env.getEventBus().register(this);
     }
+    runtimeFileSystem = env.getRuntime().getFileSystem();
   }
 
   @Override
@@ -90,7 +93,7 @@ public void afterCommand() throws AbruptExitException {
     // on the next build, which breaks commands such as `bazel config` that rely on
     // com.google.devtools.build.skyframe.MemoizingEvaluator#getDoneValues.
     if (!newLockfile.equals(oldLockfile)) {
-      updateLockfile(workspaceRoot, newLockfile);
+      updateLockfile(workspaceRoot, newLockfile, runtimeFileSystem);
     }
     this.moduleResolutionEvent = null;
     this.extensionResolutionEventsMap.clear();
@@ -190,7 +193,8 @@ private boolean shouldKeepExtension(
    * @param workspaceRoot Root of the workspace where the lockfile is located
    * @param updatedLockfile The updated lockfile data to save
    */
-  public static void updateLockfile(Path workspaceRoot, BazelLockFileValue updatedLockfile) {
+  public static void updateLockfile(
+      Path workspaceRoot, BazelLockFileValue updatedLockfile, FileSystem runtimeFileSystem) {
     RootedPath lockfilePath =
         RootedPath.toRootedPath(Root.fromPath(workspaceRoot), LabelConstants.MODULE_LOCKFILE_NAME);
     try {
@@ -202,7 +206,8 @@ public static void updateLockfile(Path workspaceRoot, BazelLockFileValue updated
                           .asPath()
                           .getParentDirectory()
                           .getRelative(LabelConstants.MODULE_DOT_BAZEL_FILE_NAME),
-                      workspaceRoot)
+                      workspaceRoot,
+                      runtimeFileSystem)
                   .toJson(updatedLockfile)
               + "\n");
     } catch (IOException e) {

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

@@ -37,7 +37,7 @@
 @GenerateTypeAdapter
 public abstract class BazelLockFileValue implements SkyValue, Postable {
 
-  public static final int LOCK_FILE_VERSION = 3;
+  public static final int LOCK_FILE_VERSION = 4;
 
   @SerializationConstant public static final SkyKey KEY = () -> SkyFunctions.BAZEL_LOCK_FILE;
 

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

@@ -29,6 +29,8 @@
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
+import com.google.devtools.build.lib.rules.repository.RepoRecordedInput;
+import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
@@ -444,7 +446,24 @@ public Location read(JsonReader jsonReader) throws IOException {
     }
   }
 
-  public static Gson createLockFileGson(Path moduleFilePath, Path workspaceRoot) {
+  private static TypeAdapter<RepoRecordedInput.File> makeRepoRecordedInputFileTypeAdapter(
+      FileSystem runtimeFileSystem) {
+    return new TypeAdapter<>() {
+      @Override
+      public void write(JsonWriter jsonWriter, RepoRecordedInput.File value) throws IOException {
+        jsonWriter.value(value.toStringInternal());
+      }
+
+      @Override
+      public RepoRecordedInput.File read(JsonReader jsonReader) throws IOException {
+        return (RepoRecordedInput.File)
+            RepoRecordedInput.File.PARSER.parse(jsonReader.nextString(), runtimeFileSystem);
+      }
+    };
+  }
+
+  public static Gson createLockFileGson(
+      Path moduleFilePath, Path workspaceRoot, FileSystem runtimeFileSystem) {
     return new GsonBuilder()
         .setPrettyPrinting()
         .disableHtmlEscaping()
@@ -468,6 +487,8 @@ public static Gson createLockFileGson(Path moduleFilePath, Path workspaceRoot) {
         .registerTypeAdapter(ModuleExtensionId.IsolationKey.class, ISOLATION_KEY_TYPE_ADAPTER)
         .registerTypeAdapter(AttributeValues.class, new AttributeValuesAdapter())
         .registerTypeAdapter(byte[].class, BYTE_ARRAY_TYPE_ADAPTER)
+        .registerTypeAdapter(
+            RepoRecordedInput.File.class, makeRepoRecordedInputFileTypeAdapter(runtimeFileSystem))
         .create();
   }
 

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

@@ -17,9 +17,9 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableTable;
-import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.events.ExtendedEventHandler.Postable;
+import com.google.devtools.build.lib.rules.repository.RepoRecordedInput;
 import com.ryanharter.auto.value.gson.GenerateTypeAdapter;
 import java.util.Optional;
 
@@ -41,7 +41,7 @@ public static Builder builder() {
   @SuppressWarnings("mutable")
   public abstract byte[] getBzlTransitiveDigest();
 
-  public abstract ImmutableMap<Label, String> getAccumulatedFileDigests();
+  public abstract ImmutableMap<RepoRecordedInput.File, String> getRecordedFileInputs();
 
   public abstract ImmutableMap<String, String> getEnvVariables();
 
@@ -60,7 +60,8 @@ public abstract static class Builder {
 
     public abstract Builder setBzlTransitiveDigest(byte[] digest);
 
-    public abstract Builder setAccumulatedFileDigests(ImmutableMap<Label, String> value);
+    public abstract Builder setRecordedFileInputs(
+        ImmutableMap<RepoRecordedInput.File, String> value);
 
     public abstract Builder setEnvVariables(ImmutableMap<String, String> value);
 

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

@@ -16,6 +16,7 @@
 
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.docgen.annot.DocCategory;
+import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.bazel.repository.downloader.DownloadManager;
 import com.google.devtools.build.lib.bazel.repository.starlark.StarlarkBaseExternalContext;
 import com.google.devtools.build.lib.runtime.ProcessWrapper;
@@ -50,6 +51,7 @@ public class ModuleExtensionContext extends StarlarkBaseExternalContext {
 
   protected ModuleExtensionContext(
       Path workingDirectory,
+      BlazeDirectories directories,
       Environment env,
       Map<String, String> envVariables,
       DownloadManager downloadManager,
@@ -62,6 +64,7 @@ protected ModuleExtensionContext(
       boolean rootModuleHasNonDevDependency) {
     super(
         workingDirectory,
+        directories,
         env,
         envVariables,
         downloadManager,

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

@@ -30,7 +30,6 @@
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Table;
-import com.google.devtools.build.lib.actions.FileValue;
 import com.google.devtools.build.lib.analysis.BlazeDirectories;
 import com.google.devtools.build.lib.bazel.repository.RepositoryOptions.LockfileMode;
 import com.google.devtools.build.lib.bazel.repository.downloader.DownloadManager;
@@ -49,6 +48,7 @@
 import com.google.devtools.build.lib.profiler.ProfilerTask;
 import com.google.devtools.build.lib.profiler.SilentCloseable;
 import com.google.devtools.build.lib.rules.repository.NeedsSkyframeRestartException;
+import com.google.devtools.build.lib.rules.repository.RepoRecordedInput;
 import com.google.devtools.build.lib.rules.repository.RepositoryFunction;
 import com.google.devtools.build.lib.runtime.ProcessWrapper;
 import com.google.devtools.build.lib.runtime.RepositoryRemoteExecutor;
@@ -62,7 +62,6 @@
 import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.util.OS;
 import com.google.devtools.build.lib.vfs.Path;
-import com.google.devtools.build.lib.vfs.RootedPath;
 import com.google.devtools.build.skyframe.SkyFunction;
 import com.google.devtools.build.skyframe.SkyFunctionException;
 import com.google.devtools.build.skyframe.SkyFunctionException.Transience;
@@ -72,7 +71,6 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
@@ -195,7 +193,7 @@ public SkyValue compute(SkyKey skyKey, Environment env)
                   extension.getEvalFactors(),
                   LockFileModuleExtension.builder()
                       .setBzlTransitiveDigest(extension.getBzlTransitiveDigest())
-                      .setAccumulatedFileDigests(moduleExtensionResult.getAccumulatedFileDigests())
+                      .setRecordedFileInputs(moduleExtensionResult.getRecordedFileInputs())
                       .setEnvVariables(extension.getEnvVars())
                       .setGeneratedRepoSpecs(generatedRepoSpecs)
                       .setModuleExtensionMetadata(moduleExtensionMetadata)
@@ -284,7 +282,7 @@ private SingleExtensionEvalValue tryGettingValueFromLockFile(
                 + extensionId
                 + "' have changed");
       }
-      if (didFilesChange(env, lockedExtension.getAccumulatedFileDigests())) {
+      if (didFilesChange(env, lockedExtension.getRecordedFileInputs())) {
         diffRecorder.record(
             "One or more files the extension '" + extensionId + "' is using have changed");
       }
@@ -386,39 +384,13 @@ private static boolean didRepoMappingsChange(
   }
 
   private static boolean didFilesChange(
-      Environment env, ImmutableMap<Label, String> accumulatedFileDigests)
+      Environment env, ImmutableMap<RepoRecordedInput.File, String> recordedFileInputs)
       throws InterruptedException, NeedsSkyframeRestartException {
-    // Turn labels into FileValue keys & get those values
-    Map<Label, FileValue.Key> fileKeys = new HashMap<>();
-    for (Label label : accumulatedFileDigests.keySet()) {
-      try {
-        RootedPath rootedPath = RepositoryFunction.getRootedPathFromLabel(label, env);
-        fileKeys.put(label, FileValue.key(rootedPath));
-      } catch (NeedsSkyframeRestartException e) {
-        throw e;
-      } catch (EvalException e) {
-        // Consider those exception to be a cause for invalidation
-        return true;
-      }
-    }
-    SkyframeLookupResult result = env.getValuesAndExceptions(fileKeys.values());
+    boolean upToDate = RepoRecordedInput.areAllValuesUpToDate(env, recordedFileInputs);
     if (env.valuesMissing()) {
       throw new NeedsSkyframeRestartException();
     }
-
-    // Compare the collected file values with the hashes stored in the lockfile
-    for (Entry<Label, String> entry : accumulatedFileDigests.entrySet()) {
-      FileValue fileValue = (FileValue) result.get(fileKeys.get(entry.getKey()));
-      try {
-        if (!entry.getValue().equals(RepositoryFunction.fileValueToMarkerValue(fileValue))) {
-          return true;
-        }
-      } catch (IOException e) {
-        // Consider those exception to be a cause for invalidation
-        return true;
-      }
-    }
-    return false;
+    return upToDate;
   }
 
   /**
@@ -951,7 +923,7 @@ public RunModuleExtensionResult run(
         }
       }
       return RunModuleExtensionResult.create(
-          moduleContext.getAccumulatedFileDigests(),
+          moduleContext.getRecordedFileInputs(),
           threadContext.getGeneratedRepoSpecs(),
           moduleExtensionMetadata,
           repoMappingRecorder.recordedEntries());
@@ -987,6 +959,7 @@ private ModuleExtensionContext createContext(
           rootUsage != null && rootUsage.getHasNonDevUseExtension();
       return new ModuleExtensionContext(
           workingDirectory,
+          directories,
           env,
           clientEnvironmentSupplier.get(),
           downloadManager,
@@ -1011,7 +984,7 @@ static final class SingleExtensionEvalFunctionException extends SkyFunctionExcep
   @AutoValue
   abstract static class RunModuleExtensionResult {
 
-    abstract ImmutableMap<Label, String> getAccumulatedFileDigests();
+    abstract ImmutableMap<RepoRecordedInput.File, String> getRecordedFileInputs();
 
     abstract ImmutableMap<String, RepoSpec> getGeneratedRepoSpecs();
 
@@ -1020,12 +993,12 @@ abstract static class RunModuleExtensionResult {
     abstract ImmutableTable<RepositoryName, String, RepositoryName> getRecordedRepoMappingEntries();
 
     static RunModuleExtensionResult create(
-        ImmutableMap<Label, String> accumulatedFileDigests,
+        ImmutableMap<RepoRecordedInput.File, String> recordedFileInputs,
         ImmutableMap<String, RepoSpec> generatedRepoSpecs,
         Optional<ModuleExtensionMetadata> moduleExtensionMetadata,
         ImmutableTable<RepositoryName, String, RepositoryName> recordedRepoMappingEntries) {
       return new AutoValue_SingleExtensionEvalFunction_RunModuleExtensionResult(
-          accumulatedFileDigests,
+          recordedFileInputs,
           generatedRepoSpecs,
           moduleExtensionMetadata,
           recordedRepoMappingEntries);

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

@@ -37,6 +37,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/events",
         "//src/main/java/com/google/devtools/build/lib/packages",
         "//src/main/java/com/google/devtools/build/lib/repository:repository_events",
+        "//src/main/java/com/google/devtools/build/lib/rules:repository/repo_recorded_input",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_directory_value",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_function",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/resolved_file_value",

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

@@ -35,6 +35,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/profiler",
         "//src/main/java/com/google/devtools/build/lib/repository:repository_events",
         "//src/main/java/com/google/devtools/build/lib/repository:request_repository_information_event",
+        "//src/main/java/com/google/devtools/build/lib/rules:repository/repo_recorded_input",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_directory_value",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/repository_function",
         "//src/main/java/com/google/devtools/build/lib/rules:repository/workspace_attribute_mapper",