Add RunfilesLibraryInfo

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

@@ -340,6 +340,7 @@ java_library(
         ":rule_configured_object_value",
         ":rule_definition_environment",
         ":run_environment_info",
+        ":runfiles_library_info",
         ":starlark/args",
         ":starlark/bazel_build_api_globals",
         ":starlark/function_transition_util",
@@ -1029,6 +1030,18 @@ java_library(
     ],
 )
 
+java_library(
+    name = "runfiles_library_info",
+    srcs = ["RunfilesLibraryInfo.java"],
+    deps = [
+        "//src/main/java/com/google/devtools/build/lib/concurrent",
+        "//src/main/java/com/google/devtools/build/lib/packages",
+        "//src/main/java/com/google/devtools/build/lib/starlarkbuildapi",
+        "//src/main/java/net/starlark/java/eval",
+        "//third_party:guava",
+    ],
+)
+
 java_library(
     name = "rule_definition_environment",
     srcs = ["RuleDefinitionEnvironment.java"],

src/main/java/com/google/devtools/build/lib/analysis/RunfilesLibraryInfo.java

@@ -0,0 +1,55 @@
+// Copyright 2022 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.analysis;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
+import com.google.devtools.build.lib.packages.BuiltinProvider;
+import com.google.devtools.build.lib.packages.NativeInfo;
+import com.google.devtools.build.lib.starlarkbuildapi.RunfilesLibraryInfoApi;
+
+/**
+ * Data-less provider that signals to direct dependents that this target is a runfiles library.
+ *
+ * <p>Rules that find this provider advertised by a dependency may use this as a signal to generate
+ * code that helps with runfiles discovery, e.g., by providing a constant containing the name of the
+ * repository that defines the rule.
+ *
+ * <p>Bazel itself uses the presence of this provider on a rule as a sign that it should include the
+ * repository mapping of the repository containing the rule in the repository mapping manifest of
+ * executable transitive dependents.
+ */
+@Immutable
+public final class RunfilesLibraryInfo extends NativeInfo implements RunfilesLibraryInfoApi {
+
+  public static final RunfilesLibraryInfoProvider PROVIDER = new RunfilesLibraryInfoProvider();
+
+  @Override
+  public RunfilesLibraryInfoProvider getProvider() {
+    return PROVIDER;
+  }
+
+  public static class RunfilesLibraryInfoProvider extends BuiltinProvider<RunfilesLibraryInfo>
+      implements RunfilesLibraryInfoApi.RunfilesLibraryInfoApiProvider {
+
+    private RunfilesLibraryInfoProvider() {
+      super("RunfilesLibraryInfo", RunfilesLibraryInfo.class);
+    }
+
+    @Override
+    public RunfilesLibraryInfoApi constructor() {
+      return new RunfilesLibraryInfo();
+    }
+  }
+}

src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkModules.java

@@ -17,6 +17,7 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.analysis.ActionsProvider;
 import com.google.devtools.build.lib.analysis.DefaultInfo;
+import com.google.devtools.build.lib.analysis.RunfilesLibraryInfo;
 import com.google.devtools.build.lib.analysis.OutputGroupInfo;
 import com.google.devtools.build.lib.analysis.RunEnvironmentInfo;
 import com.google.devtools.build.lib.packages.StarlarkLibrary;
@@ -46,5 +47,6 @@ public static void addPredeclared(ImmutableMap.Builder<String, Object> predeclar
     predeclared.put("Actions", ActionsProvider.INSTANCE);
     predeclared.put("DefaultInfo", DefaultInfo.PROVIDER);
     predeclared.put("RunEnvironmentInfo", RunEnvironmentInfo.PROVIDER);
+    predeclared.put("RunfilesLibraryInfo", RunfilesLibraryInfo.PROVIDER);
   }
 }

src/main/java/com/google/devtools/build/lib/starlarkbuildapi/RunfilesLibraryInfoApi.java

@@ -0,0 +1,44 @@
+// Copyright 2022 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.starlarkbuildapi;
+
+import com.google.devtools.build.docgen.annot.DocCategory;
+import com.google.devtools.build.docgen.annot.StarlarkConstructor;
+import com.google.devtools.build.lib.starlarkbuildapi.core.ProviderApi;
+import com.google.devtools.build.lib.starlarkbuildapi.core.StructApi;
+import net.starlark.java.annot.StarlarkBuiltin;
+import net.starlark.java.annot.StarlarkMethod;
+
+@StarlarkBuiltin(
+    name = "RunfilesLibraryInfo",
+    category = DocCategory.PROVIDER,
+    doc = "Signals to direct dependents as well as Bazel itself that this target is a runfiles "
+        + "library. For example, rules for compiled languages may choose to generate and compile "
+        + "additional code that gives access to the name of the repository defining the current "
+        + "target if they find this provider advertised by a direct dependency.<p>This provider "
+        + "carries no data.")
+public interface RunfilesLibraryInfoApi extends StructApi {
+
+  @StarlarkBuiltin(name = "Provider", category = DocCategory.PROVIDER, documented = false)
+  interface RunfilesLibraryInfoApiProvider extends ProviderApi {
+
+    @StarlarkMethod(
+        name = "RunfilesLibraryInfo",
+        doc = "The <code>RunfilesLibraryInfo</code> constructor.",
+        selfCall = true)
+    @StarlarkConstructor
+    RunfilesLibraryInfoApi constructor();
+  }
+}

src/test/java/com/google/devtools/build/lib/starlark/BUILD

@@ -46,6 +46,7 @@ java_test(
         "//src/main/java/com/google/devtools/build/lib/analysis:file_provider",
         "//src/main/java/com/google/devtools/build/lib/analysis:resolved_toolchain_context",
         "//src/main/java/com/google/devtools/build/lib/analysis:run_environment_info",
+        "//src/main/java/com/google/devtools/build/lib/analysis:runfiles_library_info",
         "//src/main/java/com/google/devtools/build/lib/analysis:starlark/args",
         "//src/main/java/com/google/devtools/build/lib/analysis:starlark/starlark_exec_group_collection",
         "//src/main/java/com/google/devtools/build/lib/analysis:test/analysis_test_result_info",

src/test/java/com/google/devtools/build/lib/starlark/StarlarkIntegrationTest.java

@@ -30,6 +30,7 @@
 import com.google.devtools.build.lib.analysis.FilesToRunProvider;
 import com.google.devtools.build.lib.analysis.OutputGroupInfo;
 import com.google.devtools.build.lib.analysis.RunEnvironmentInfo;
+import com.google.devtools.build.lib.analysis.RunfilesLibraryInfo;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
 import com.google.devtools.build.lib.analysis.config.StarlarkDefinedConfigTransition;
 import com.google.devtools.build.lib.analysis.configuredtargets.FileConfiguredTarget;
@@ -3652,4 +3653,36 @@ public void nonExecutableStarlarkRuleReturningTestEnvironmentProducesAWarning()
             + " non-test target has no effect",
         ImmutableSet.of(EventKind.WARNING));
   }
+
+  @Test
+  public void runfilesLibraryInfoCanBeReturnedAndQueried() throws Exception {
+    scratch.file(
+        "examples/rules.bzl",
+        "def my_runfiles_library_impl(ctx):",
+        "  return [RunfilesLibraryInfo()]",
+        "my_runfiles_library = rule(implementation = my_runfiles_library_impl)",
+        "def language_rule_impl(ctx):",
+        "  if RunfilesLibraryInfo not in ctx.attr.dep:",
+        "    fail('dep does not advertise RunfilesLibraryInfo')",
+        "language_rule = rule(",
+        "  implementation = language_rule_impl,",
+        "  attrs = {'dep': attr.label()},",
+        ")"
+    );
+    scratch.file(
+        "examples/BUILD",
+        "load(':rules.bzl', 'language_rule', 'my_runfiles_library')",
+        "my_runfiles_library(name = 'runfiles_library')",
+        "language_rule(",
+        "  name = 'target',",
+        "  dep = ':runfiles_library',",
+        ")"
+    );
+
+    ConfiguredTarget runfilesLibrary = getConfiguredTarget("//examples:runfiles_library");
+    assertThat(runfilesLibrary.get(RunfilesLibraryInfo.PROVIDER)).isNotNull();
+
+    // Succeeds only if targets can be queried for the presence of RunfilesLibraryInfo in Starlark.
+    getConfiguredTarget("//examples:target");
+  }
 }