Introduce aliases in @bazel_tools for protobuf

Certain flags have default label values pointing to within @com_google_protobuf. Since the built-in module bazel_tools already has a dependency on @com_google_protobuf, we can simply create aliases for those targets in @bazel_tools, which removes the need for protobuf to be a well-known module.

Related: #14279
PiperOrigin-RevId: 459066103
Change-Id: I583f28ace7afe2bc91997293bb9870f836e393eb

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

@@ -24,12 +24,11 @@
 public abstract class ModuleKey {
 
   /**
-   * A mapping from module name to repository name.
+   * A mapping from module name to repository name for certain special "well-known" modules.
    *
-   * <p>For some well known modules, their repository names are referenced in default label values
-   * of some native rules' attributes and command line flags, which don't go through repo mappings.
-   * Therefore, we have to keep its canonical repository name the same as its well known repository
-   * name. Eg. "@com_google_protobuf//:protoc" is used for --proto_compiler flag.
+   * <p>The repository name of certain modules are required to be exact strings (instead of the
+   * normal format seen in {@link #getCanonicalRepoName()}) due to backwards compatibility reasons.
+   * For example, bazel_tools must be known as "@bazel_tools" for WORKSPACE repos to work correctly.
    *
    * <p>NOTE(wyv): We don't prepend an '@' to the repo names of well-known modules. This is because
    * we still need the repo name to be 'bazel_tools' (not '@bazel_tools') since the command line
@@ -38,16 +37,15 @@ public abstract class ModuleKey {
    * Bzlmod is not enabled. On the other hand, this means we cannot write '@@bazel_tools//:thing' to
    * bypass repo mapping at all, which can be awkward.
    *
-   * <p>TODO(wyv): After we get rid of usage of com_google_protobuf in flag defaults, and make all
-   * flag values go through repo mapping, we can remove the concept of well-known modules
-   * altogether.
+   * <p>TODO(wyv): After we make all flag values go through repo mapping, we can remove the concept
+   * of well-known modules altogether.
    */
   private static final ImmutableMap<String, RepositoryName> WELL_KNOWN_MODULES =
       ImmutableMap.of(
-          "com_google_protobuf", RepositoryName.createUnvalidated("com_google_protobuf"),
-          "protobuf", RepositoryName.createUnvalidated("com_google_protobuf"),
-          "bazel_tools", RepositoryName.BAZEL_TOOLS,
-          "local_config_platform", RepositoryName.createUnvalidated("local_config_platform"));
+          "bazel_tools",
+          RepositoryName.BAZEL_TOOLS,
+          "local_config_platform",
+          RepositoryName.createUnvalidated("local_config_platform"));
 
   public static final ModuleKey ROOT = create("", Version.EMPTY);
 

src/main/java/com/google/devtools/build/lib/bazel/rules/java/proto/BazelJavaLiteProtoAspect.java

@@ -22,7 +22,7 @@
 public class BazelJavaLiteProtoAspect extends JavaLiteProtoAspect {
 
   public static final String DEFAULT_PROTO_TOOLCHAIN_LABEL =
-      "@com_google_protobuf//:javalite_toolchain";
+      "@bazel_tools//tools/proto:javalite_toolchain";
 
   public BazelJavaLiteProtoAspect(RuleDefinitionEnvironment env) {
     super(BazelJavaSemantics.INSTANCE, DEFAULT_PROTO_TOOLCHAIN_LABEL, env);

src/main/java/com/google/devtools/build/lib/bazel/rules/java/proto/BazelJavaProtoAspect.java

@@ -36,7 +36,7 @@ public BazelJavaProtoAspect(RuleDefinitionEnvironment env) {
     super(
         BazelJavaSemantics.INSTANCE,
         new NoopRpcSupport(),
-        "@com_google_protobuf//:java_toolchain",
+        "@bazel_tools//tools/proto:java_toolchain",
         env);
   }
 

src/main/java/com/google/devtools/build/lib/rules/cpp/proto/CcProtoAspect.java

@@ -82,7 +82,7 @@ public abstract class CcProtoAspect extends NativeAspectClass implements Configu
   private static final LabelLateBoundDefault<?> PROTO_TOOLCHAIN_LABEL =
       LabelLateBoundDefault.fromTargetConfiguration(
           ProtoConfiguration.class,
-          Label.parseAbsoluteUnchecked("@com_google_protobuf//:cc_toolchain"),
+          Label.parseAbsoluteUnchecked("@bazel_tools//tools/proto:cc_toolchain"),
           (rule, attributes, protoConfig) -> protoConfig.protoToolchainForCc());
 
   private final CppSemantics cppSemantics;

src/main/java/com/google/devtools/build/lib/rules/proto/ProtoConfiguration.java

@@ -94,7 +94,7 @@ public static class Options extends FragmentOptions {
 
     @Option(
         name = "proto_toolchain_for_javalite",
-        defaultValue = "@com_google_protobuf//:javalite_toolchain",
+        defaultValue = "@bazel_tools//tools/proto:javalite_toolchain",
         converter = CoreOptionConverters.LabelConverter.class,
         documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
         effectTags = {OptionEffectTag.AFFECTS_OUTPUTS, OptionEffectTag.LOADING_AND_ANALYSIS},
@@ -103,7 +103,7 @@ public static class Options extends FragmentOptions {
 
     @Option(
         name = "proto_toolchain_for_java",
-        defaultValue = "@com_google_protobuf//:java_toolchain",
+        defaultValue = "@bazel_tools//tools/proto:java_toolchain",
         converter = CoreOptionConverters.EmptyToNullLabelConverter.class,
         documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
         effectTags = {OptionEffectTag.AFFECTS_OUTPUTS, OptionEffectTag.LOADING_AND_ANALYSIS},
@@ -122,7 +122,7 @@ public static class Options extends FragmentOptions {
 
     @Option(
         name = "proto_toolchain_for_cc",
-        defaultValue = "@com_google_protobuf//:cc_toolchain",
+        defaultValue = "@bazel_tools//tools/proto:cc_toolchain",
         converter = CoreOptionConverters.EmptyToNullLabelConverter.class,
         documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
         effectTags = {OptionEffectTag.AFFECTS_OUTPUTS, OptionEffectTag.LOADING_AND_ANALYSIS},

src/main/java/com/google/devtools/build/lib/rules/proto/ProtoConstants.java

@@ -17,13 +17,14 @@
 /** Constants used in Proto rules. */
 public final class ProtoConstants {
   /** Default label for proto compiler. */
-  static final String DEFAULT_PROTOC_LABEL =  "@com_google_protobuf//:protoc";
+  static final String DEFAULT_PROTOC_LABEL =  "@bazel_tools//tools/proto:protoc";
 
   /** Default label for java proto toolchains. */
-  static final String DEFAULT_JAVA_PROTO_LABEL = "@com_google_protobuf//:java_toolchain";
+  static final String DEFAULT_JAVA_PROTO_LABEL = "@bazel_tools//tools/proto:java_toolchain";
 
   /** Default label for java lite proto toolchains. */
-  static final String DEFAULT_JAVA_LITE_PROTO_LABEL = "@com_google_protobuf//:javalite_toolchain";
+  static final String DEFAULT_JAVA_LITE_PROTO_LABEL =
+      "@bazel_tools//tools/proto:javalite_toolchain";
 
   /**
    * This constant is used in ProtoCompileActionBuilder to generate an error message that's

src/main/starlark/builtins_bzl/common/proto/proto_semantics.bzl

@@ -20,7 +20,7 @@ def _preprocess(ctx):
     pass
 
 semantics = struct(
-    PROTO_COMPILER_LABEL = "@com_google_protobuf//:protoc",
+    PROTO_COMPILER_LABEL = "@bazel_tools//tools/proto:protoc",
     EXTRA_ATTRIBUTES = {
         "import_prefix": attr.string(),
     },

src/test/java/com/google/devtools/build/lib/analysis/mock/BazelAnalysisMock.java

@@ -315,6 +315,14 @@ public void setupMockClient(MockToolsConfig config, List<String> workspaceConten
         "package_group(name='config_feature_flag', packages=['//...'])",
         "package_group(name='config_feature_flag_Setter', packages=['//...'])");
 
+    config.create(
+        "embedded_tools/tools/proto/BUILD",
+        "package(default_visibility=['//visibility:public'])",
+        "alias(name='protoc',actual='@com_google_protobuf//:protoc')",
+        "alias(name='javalite_toolchain',actual='@com_google_protobuf//:javalite_toolchain')",
+        "alias(name='java_toolchain',actual='@com_google_protobuf//:java_toolchain')",
+        "alias(name='cc_toolchain',actual='@com_google_protobuf//:cc_toolchain')");
+
     config.create(
         "embedded_tools/tools/zip/BUILD",
         "package(default_visibility=['//visibility:public'])",

src/test/java/com/google/devtools/build/lib/rules/proto/BUILD

@@ -39,7 +39,6 @@ java_test(
     deps = [
         "//src/main/java/com/google/devtools/build/lib/analysis:transitive_info_collection",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
-        "//src/main/java/com/google/devtools/build/lib/packages",
         "//src/main/java/com/google/devtools/build/lib/rules/proto",
         "//src/test/java/com/google/devtools/build/lib/analysis/util",
         "//src/test/java/com/google/devtools/build/lib/packages:testutil",

src/test/java/com/google/devtools/build/lib/rules/proto/ProtoLangToolchainTest.java

@@ -21,9 +21,6 @@
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
 import com.google.devtools.build.lib.cmdline.Label;
-import com.google.devtools.build.lib.cmdline.LabelSyntaxException;
-import com.google.devtools.build.lib.packages.Provider;
-import com.google.devtools.build.lib.packages.StarlarkProvider;
 import com.google.devtools.build.lib.packages.util.MockProtoSupport;
 import com.google.devtools.build.lib.testutil.TestConstants;
 import org.junit.Before;
@@ -42,12 +39,6 @@ public void setUp() throws Exception {
     invalidatePackages();
   }
 
-  Provider.Key getStarlarkProtoLangToolchainInfoKey() throws LabelSyntaxException {
-    return new StarlarkProvider.Key(
-        Label.parseCanonical("@_builtins//:common/proto/proto_common.bzl"),
-        "ProtoLangToolchainInfo");
-  }
-
   private void validateProtoLangToolchain(ProtoLangToolchainProvider toolchain) throws Exception {
     assertThat(toolchain.outReplacementFormatFlag()).isEqualTo("cmd-line:%s");
     assertThat(toolchain.pluginFormatFlag()).isEqualTo("--plugin=%s");
@@ -63,9 +54,11 @@ private void validateProtoLangToolchain(ProtoLangToolchainProvider toolchain) th
     assertThat(toolchain.mnemonic()).isEqualTo("MyMnemonic");
   }
 
-  private void validateProtoCompiler(ProtoLangToolchainProvider toolchain, Label protoCompiler) {
+  private void validateProtoCompiler(ProtoLangToolchainProvider toolchain, String protocLabel)
+      throws Exception {
+    Label actualProtocLabel = getConfiguredTarget(protocLabel).getActual().getLabel();
     assertThat(toolchain.protoc().getExecutable().prettyPrint())
-        .isEqualTo(protoCompiler.toPathFragment().getPathString());
+        .isEqualTo(actualProtocLabel.toPathFragment().getPathString());
   }
 
   @Test
@@ -96,10 +89,9 @@ public void protoToolchain() throws Exception {
     update(ImmutableList.of("//foo:toolchain"), false, 1, true, new EventBus());
     ProtoLangToolchainProvider toolchain =
         ProtoLangToolchainProvider.get(getConfiguredTarget("//foo:toolchain"));
-    Label protoc = Label.parseAbsoluteUnchecked(ProtoConstants.DEFAULT_PROTOC_LABEL);
 
     validateProtoLangToolchain(toolchain);
-    validateProtoCompiler(toolchain, protoc);
+    validateProtoCompiler(toolchain, ProtoConstants.DEFAULT_PROTOC_LABEL);
   }
 
   @Test
@@ -131,10 +123,9 @@ public void protoToolchain_setProtoCompiler() throws Exception {
 
     ProtoLangToolchainProvider toolchain =
         ProtoLangToolchainProvider.get(getConfiguredTarget("//foo:toolchain"));
-    Label protoc = Label.parseAbsoluteUnchecked("//third_party/x:compiler");
 
     validateProtoLangToolchain(toolchain);
-    validateProtoCompiler(toolchain, protoc);
+    validateProtoCompiler(toolchain, "//third_party/x:compiler");
   }
 
   @Test
@@ -164,10 +155,9 @@ public void protoToolchainBlacklistProtoLibraries() throws Exception {
     update(ImmutableList.of("//foo:toolchain"), false, 1, true, new EventBus());
     ProtoLangToolchainProvider toolchain =
         ProtoLangToolchainProvider.get(getConfiguredTarget("//foo:toolchain"));
-    Label protoc = Label.parseAbsoluteUnchecked(ProtoConstants.DEFAULT_PROTOC_LABEL);
 
     validateProtoLangToolchain(toolchain);
-    validateProtoCompiler(toolchain, protoc);
+    validateProtoCompiler(toolchain, ProtoConstants.DEFAULT_PROTOC_LABEL);
   }
 
   @Test
@@ -197,10 +187,9 @@ public void protoToolchainBlacklistTransitiveProtos() throws Exception {
     update(ImmutableList.of("//foo:toolchain"), false, 1, true, new EventBus());
     ProtoLangToolchainProvider toolchain =
         ProtoLangToolchainProvider.get(getConfiguredTarget("//foo:toolchain"));
-    Label protoc = Label.parseAbsoluteUnchecked(ProtoConstants.DEFAULT_PROTOC_LABEL);
 
     validateProtoLangToolchain(toolchain);
-    validateProtoCompiler(toolchain, protoc);
+    validateProtoCompiler(toolchain, ProtoConstants.DEFAULT_PROTOC_LABEL);
   }
 
   @Test

tools/BUILD

@@ -25,6 +25,7 @@ filegroup(
         "//tools/objc:srcs",
         "//tools/osx:srcs",
         "//tools/osx/crosstool:srcs",
+        "//tools/proto:srcs",
         "//tools/windows:srcs",
         "//tools/test:srcs",
         "//tools/test/CoverageOutputGenerator/java/com/google/devtools/coverageoutputgenerator:srcs",
@@ -60,6 +61,7 @@ filegroup(
         "//tools/def_parser:srcs",
         "//tools/windows:srcs",
         "//tools/platforms:srcs",
+        "//tools/proto:srcs",
         "//tools/objc:srcs",
         "//tools/python:embedded_tools",
         "//tools/runfiles:embedded_tools",

tools/proto/BUILD

@@ -0,0 +1,28 @@
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"] + ["**/*"]),
+)
+
+exports_files(["BUILD"])
+
+alias(
+    name = "protoc",
+    actual = "@com_google_protobuf//:protoc",
+)
+
+alias(
+    name = "javalite_toolchain",
+    actual = "@com_google_protobuf//:javalite_toolchain",
+)
+
+alias(
+    name = "java_toolchain",
+    actual = "@com_google_protobuf//:java_toolchain",
+)
+
+alias(
+    name = "cc_toolchain",
+    actual = "@com_google_protobuf//:cc_toolchain",
+)