From 47774b9a21948507c0ec0c8219b3a4c895fe4728 Mon Sep 17 00:00:00 2001
From: UebelAndre <github@uebelandre.com>
Date: Mon, 3 Jan 2022 16:59:12 -0800
Subject: [PATCH] Added `native.bazel_version` for use in BUILD and bzl files

---
 .../packages/BazelStarlarkEnvironment.java    |  6 ++-
 .../StarlarkRepositoryIntegrationTest.java    | 42 +++++++++++++++++++
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/google/devtools/build/lib/packages/BazelStarlarkEnvironment.java b/src/main/java/com/google/devtools/build/lib/packages/BazelStarlarkEnvironment.java
index a0af5ec1c3c433..e28530554a7fee 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/BazelStarlarkEnvironment.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/BazelStarlarkEnvironment.java
@@ -70,7 +70,7 @@ public final class BazelStarlarkEnvironment {
     this.ruleFunctions = ruleFunctions;
     this.uninjectedBuildBzlNativeBindings =
         createUninjectedBuildBzlNativeBindings(
-            ruleFunctions, packageFunction, environmentExtensions);
+            ruleFunctions, packageFunction, environmentExtensions, version);
     this.workspaceBzlNativeBindings = createWorkspaceBzlNativeBindings(ruleClassProvider, version);
     this.uninjectedBuildBzlEnv =
         createUninjectedBuildBzlEnv(ruleClassProvider, uninjectedBuildBzlNativeBindings);
@@ -143,7 +143,8 @@ public ImmutableMap<String, Object> getBzlmodBzlEnv() {
   private static ImmutableMap<String, Object> createUninjectedBuildBzlNativeBindings(
       Map<String, ?> ruleFunctions,
       Object packageFunction,
-      List<PackageFactory.EnvironmentExtension> environmentExtensions) {
+      List<PackageFactory.EnvironmentExtension> environmentExtensions,
+      String version) {
     ImmutableMap.Builder<String, Object> env = new ImmutableMap.Builder<>();
     env.putAll(StarlarkNativeModule.BINDINGS_FOR_BUILD_FILES);
     env.putAll(ruleFunctions);
@@ -151,6 +152,7 @@ private static ImmutableMap<String, Object> createUninjectedBuildBzlNativeBindin
     for (PackageFactory.EnvironmentExtension ext : environmentExtensions) {
       ext.updateNative(env);
     }
+    env.put("bazel_version", version);
     return env.build();
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/starlark/StarlarkRepositoryIntegrationTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/starlark/StarlarkRepositoryIntegrationTest.java
index 8968e41573dc03..e1e0d6692b0434 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/starlark/StarlarkRepositoryIntegrationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/starlark/StarlarkRepositoryIntegrationTest.java
@@ -537,4 +537,46 @@ public void testPackageAndRepositoryNameFunctionsInExternalRepository() throws E
     getConfiguredTarget("@foo//p:BUILD"); // (loadPackage(@foo//p) would suffice)
     assertContainsEvent("repo=@foo pkg=p");
   }
+
+  @Test
+  public void testNativeBazelVersion() throws Exception {
+    reporter.removeHandler(failFastHandler);
+    scratch.file(
+        "repo_bzl_ver.bzl",
+        "def _repo_impl(repository_ctx):",
+        "  repository_ctx.file('BUILD', '')",
+        "  repository_ctx.file('defs.bzl', 'BAZEL_VERSION = \"' + native.bazel_version + '\"')",
+        "  repository_ctx.file('WORKSPACE', '')",
+        "",
+        "repo = repository_rule(",
+        "    implementation=_repo_impl,",
+        "    local=True)");
+    scratch.file(
+        "bzl_ver.bzl",
+        "load('@repo2//:defs.bzl', 'BAZEL_VERSION')",
+        "def _impl(ctx):",
+        "  if BAZEL_VERSION == native.bazel_version:",
+        "    print('native.bazel_version matches')",
+        "  else:",
+        "    fail(BAZEL_VERSION + ' does not equal ' + native.bazel_version)",
+        "  output = ctx.actions.declare_file(ctx.label.name + '.txt')",
+        "  ctx.actions.write(output = output, content = native.bazel_version)",
+        "  return DefaultInfo(files = depset([output]))",
+        "",
+        "check = rule(",
+        "    implementation=_impl)");
+    scratch.file("BUILD", "load('@//:bzl_ver.bzl', 'check')", "check(name = 'check')");
+    scratch.overwriteFile(
+        rootDirectory.getRelative("WORKSPACE").getPathString(), 
+        new ImmutableList.Builder<String>()
+        .addAll(analysisMock.getWorkspaceContents(mockToolsConfig))
+        .add("load('@//:repo_bzl_ver.bzl', 'repo')")
+        .add("repo(name = 'repo2')")
+        .build());
+
+    invalidatePackages();
+
+    getConfiguredTarget("//:check");
+    assertContainsEvent("native.bazel_version matches");
+  }
 }