Add support for use_repo_rule in MODULE.bazel files

This CL introduces a new directive in the MDOULE.bazel file, `use_repo_rule`, which is a convenient way to declare repos that are only visible to the current module. See #17141 (comment) for example usage. Under the hood, this is implemented as an "innate" module extension for each module that uses `use_repo_rule`. The ID of this extension is a fake one: with the bzl file label of `@@name~version//:MODULE.bazel` and name of `__innate`. Each tag of this extension corresponds to a repo. The name of the tag is the string `${repo_rule_bzl_label}%${repo_rule_name}`, and the attributes of the tag are the attributes of the repo. Fixes #17141. PiperOrigin-RevId: 567722226 Change-Id: I16b8dc562dd20a676118867d831d3b2f5631f767
bazelbuild · Sep 27, 2023 · b3401af · b3401af
1 parent ea4ab7d
commit b3401af
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Showing 9 changed files with 739 additions and 184 deletions.
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BUILD b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/BUILD
@@ -25,6 +25,7 @@ java_library(
     ],
     deps = [
         "//src/main/java/com/google/devtools/build/lib/cmdline",
+        "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//src/main/java/com/google/devtools/build/skyframe:skyframe-objects",
         "//src/main/java/net/starlark/java/eval",
         "//third_party:auto_value",
@@ -192,6 +193,7 @@ java_library(
         ":module_extension",
         ":module_extension_metadata",
         ":registry",
+        ":repo_rule_creator",
         ":resolution",
         "//src/main/java/com/google/devtools/build/docgen/annot",
         "//src/main/java/com/google/devtools/build/lib:runtime",

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleExtensionId.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleExtensionId.java
@@ -35,6 +35,12 @@ public abstract class ModuleExtensionId {
               ModuleExtensionId::getIsolationKey,
               emptiesFirst(IsolationKey.LEXICOGRAPHIC_COMPARATOR));
 
+  /**
+   * The "magical" name of innate extensions, which are fabricated extensions that modules with
+   * usages of {@code use_repo_rule} have.
+   */
+  public static final String INNATE_EXTENSION_NAME = "_repo_rules";
+
   /** A unique identifier for a single isolated usage of a fixed module extension. */
   @AutoValue
   abstract static class IsolationKey {
@@ -75,6 +81,10 @@ public static ModuleExtensionId create(
     return new AutoValue_ModuleExtensionId(bzlFileLabel, extensionName, isolationKey);
   }
 
+  public final boolean isInnate() {
+    return getExtensionName().equals(INNATE_EXTENSION_NAME);
+  }
+
   public String asTargetString() {
     String isolationKeyPart = getIsolationKey().map(key -> "%" + key).orElse("");
     return String.format(

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleFileFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleFileFunction.java
@@ -24,9 +24,7 @@
 import com.google.devtools.build.lib.actions.FileValue;
 import com.google.devtools.build.lib.bazel.bzlmod.ModuleFileValue.NonRootModuleFileValue;
 import com.google.devtools.build.lib.bazel.bzlmod.ModuleFileValue.RootModuleFileValue;
-import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.cmdline.LabelConstants;
-import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
 import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.packages.DotBazelFileSyntaxChecker;
@@ -43,7 +41,6 @@
 import com.google.devtools.build.lib.util.Fingerprint;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.Path;
-import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.RootedPath;
 import com.google.devtools.build.skyframe.SkyFunction;
@@ -350,15 +347,11 @@ private GetModuleFileResult getModuleFile(
       if (env.getValue(FileValue.key(moduleFilePath)) == null) {
         return null;
       }
-      Label moduleFileLabel =
-          Label.createUnvalidated(
-              PackageIdentifier.create(key.getCanonicalRepoName(), PathFragment.EMPTY_FRAGMENT),
-              LabelConstants.MODULE_DOT_BAZEL_FILE_NAME.getBaseName());
       GetModuleFileResult result = new GetModuleFileResult();
       result.moduleFile =
           ModuleFile.create(
               readModuleFile(moduleFilePath.asPath()),
-              moduleFileLabel.getUnambiguousCanonicalForm());
+              key.moduleFileLabel().getUnambiguousCanonicalForm());
       return result;
     }
 

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleFileGlobals.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleFileGlobals.java
@@ -443,9 +443,15 @@ public ModuleExtensionProxy useExtension(
       String extensionName,
       boolean devDependency,
       boolean isolate,
-      StarlarkThread thread) {
+      StarlarkThread thread)
+      throws EvalException {
     hadNonModuleCall = true;
 
+    if (extensionName.equals(ModuleExtensionId.INNATE_EXTENSION_NAME)) {
+      throw Starlark.errorf(
+          "innate extensions cannot be directly used; try `use_repo_rule` instead");
+    }
+
     String extensionBzlFile = normalizeLabelString(rawExtensionBzlFile);
     ModuleExtensionUsageBuilder newUsageBuilder =
         new ModuleExtensionUsageBuilder(
@@ -560,11 +566,11 @@ private ModuleExtensionProxy(boolean devDependency) {
         this.devDependency = devDependency;
       }
 
-      void addImport(String localRepoName, String exportedName, Location location)
+      void addImport(String localRepoName, String exportedName, String byWhat, Location location)
           throws EvalException {
         RepositoryName.validateUserProvidedRepoName(localRepoName);
         RepositoryName.validateUserProvidedRepoName(exportedName);
-        addRepoNameUsage(localRepoName, "by a use_repo() call", location);
+        addRepoNameUsage(localRepoName, byWhat, location);
         if (imports.containsValue(exportedName)) {
           String collisionRepoName = imports.inverse().get(exportedName);
           throw Starlark.errorf(
@@ -577,26 +583,33 @@ void addImport(String localRepoName, String exportedName, Location location)
         }
       }
 
-      @Nullable
+      class TagCallable implements StarlarkValue {
+        final String tagName;
+
+        TagCallable(String tagName) {
+          this.tagName = tagName;
+        }
+
+        @StarlarkMethod(
+            name = "call",
+            selfCall = true,
+            documented = false,
+            extraKeywords = @Param(name = "kwargs"),
+            useStarlarkThread = true)
+        public void call(Dict<String, Object> kwargs, StarlarkThread thread) {
+          tags.add(
+              Tag.builder()
+                  .setTagName(tagName)
+                  .setAttributeValues(AttributeValues.create(kwargs))
+                  .setDevDependency(devDependency)
+                  .setLocation(thread.getCallerLocation())
+                  .build());
+        }
+      }
+
       @Override
-      public Object getValue(String tagName) throws EvalException {
-        return new StarlarkValue() {
-          @StarlarkMethod(
-              name = "call",
-              selfCall = true,
-              documented = false,
-              extraKeywords = @Param(name = "kwargs"),
-              useStarlarkThread = true)
-          public void call(Dict<String, Object> kwargs, StarlarkThread thread) {
-            tags.add(
-                Tag.builder()
-                    .setTagName(tagName)
-                    .setAttributeValues(AttributeValues.create(kwargs))
-                    .setDevDependency(devDependency)
-                    .setLocation(thread.getCallerLocation())
-                    .build());
-          }
-        };
+      public TagCallable getValue(String tagName) throws EvalException {
+        return new TagCallable(tagName);
       }
 
       @Override
@@ -651,11 +664,85 @@ public void useRepo(
     hadNonModuleCall = true;
     Location location = thread.getCallerLocation();
     for (String arg : Sequence.cast(args, String.class, "args")) {
-      extensionProxy.addImport(arg, arg, location);
+      extensionProxy.addImport(arg, arg, "by a use_repo() call", location);
     }
     for (Map.Entry<String, String> entry :
         Dict.cast(kwargs, String.class, String.class, "kwargs").entrySet()) {
-      extensionProxy.addImport(entry.getKey(), entry.getValue(), location);
+      extensionProxy.addImport(entry.getKey(), entry.getValue(), "by a use_repo() call", location);
+    }
+  }
+
+  @StarlarkMethod(
+      name = "use_repo_rule",
+      doc =
+          "Returns a proxy value that can be directly invoked in the MODULE.bazel file as a"
+              + " repository rule, one or more times. Repos created in such a way are only visible"
+              + " to the current module, under the name declared using the <code>name</code>"
+              + " attribute on the proxy. The implicit Boolean <code>dev_dependency</code>"
+              + " attribute can also be used on the proxy to denote that a certain repo is only to"
+              + " be created when the current module is the root module.",
+      parameters = {
+        @Param(
+            name = "repo_rule_bzl_file",
+            doc = "A label to the Starlark file defining the repo rule."),
+        @Param(
+            name = "repo_rule_name",
+            doc =
+                "The name of the repo rule to use. A symbol with this name must be exported by the"
+                    + " Starlark file."),
+      },
+      useStarlarkThread = true)
+  public RepoRuleProxy useRepoRule(String bzlFile, String ruleName, StarlarkThread thread) {
+    hadNonModuleCall = true;
+    // The builder for the singular "innate" extension of this module. Note that there's only one
+    // such usage (and it's fabricated), so the usage location just points to this file.
+    ModuleExtensionUsageBuilder newUsageBuilder =
+        new ModuleExtensionUsageBuilder(
+            "//:MODULE.bazel",
+            ModuleExtensionId.INNATE_EXTENSION_NAME,
+            /* isolate= */ false,
+            Location.fromFile(thread.getCallerLocation().file()));
+    for (ModuleExtensionUsageBuilder usageBuilder : extensionUsageBuilders) {
+      if (usageBuilder.extensionBzlFile.equals(newUsageBuilder.extensionBzlFile)
+          && usageBuilder.extensionName.equals(newUsageBuilder.extensionName)) {
+        return new RepoRuleProxy(usageBuilder, bzlFile + '%' + ruleName);
+      }
+    }
+    extensionUsageBuilders.add(newUsageBuilder);
+    return new RepoRuleProxy(newUsageBuilder, bzlFile + '%' + ruleName);
+  }
+
+  @StarlarkBuiltin(name = "repo_rule_proxy", documented = false)
+  class RepoRuleProxy implements StarlarkValue {
+    private final ModuleExtensionUsageBuilder usageBuilder;
+    private final String tagName;
+
+    private RepoRuleProxy(ModuleExtensionUsageBuilder usageBuilder, String tagName) {
+      this.usageBuilder = usageBuilder;
+      this.tagName = tagName;
+    }
+
+    @StarlarkMethod(
+        name = "call",
+        selfCall = true,
+        documented = false,
+        parameters = {
+          @Param(name = "name", positional = false, named = true),
+          @Param(name = "dev_dependency", positional = false, named = true, defaultValue = "False")
+        },
+        extraKeywords = @Param(name = "kwargs"),
+        useStarlarkThread = true)
+    public void call(
+        String name, boolean devDependency, Dict<String, Object> kwargs, StarlarkThread thread)
+        throws EvalException {
+      RepositoryName.validateUserProvidedRepoName(name);
+      if (ignoreDevDeps && devDependency) {
+        return;
+      }
+      kwargs.putEntry("name", name);
+      ModuleExtensionProxy extensionProxy = usageBuilder.getProxy(devDependency);
+      extensionProxy.getValue(tagName).call(kwargs, thread);
+      extensionProxy.addImport(name, name, "by a repo rule", thread.getCallerLocation());
     }
   }
 

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleKey.java b/src/main/java/com/google/devtools/build/lib/bazel/bzlmod/ModuleKey.java
@@ -18,7 +18,11 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableMap;
+import com.google.devtools.build.lib.cmdline.Label;
+import com.google.devtools.build.lib.cmdline.LabelConstants;
+import com.google.devtools.build.lib.cmdline.PackageIdentifier;
 import com.google.devtools.build.lib.cmdline.RepositoryName;
+import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.Comparator;
 import java.util.List;
 
@@ -62,6 +66,13 @@ public static ModuleKey create(String name, Version version) {
   /** The version of the module. Must be empty iff the module has a {@link NonRegistryOverride}. */
   public abstract Version getVersion();
 
+  /** Returns the label that points to the MODULE.bazel file of this module. */
+  public final Label moduleFileLabel() {
+    return Label.createUnvalidated(
+        PackageIdentifier.create(getCanonicalRepoName(), PathFragment.EMPTY_FRAGMENT),
+        LabelConstants.MODULE_DOT_BAZEL_FILE_NAME.getBaseName());
+  }
+
   @Override
   public final String toString() {
     if (this.equals(ROOT)) {