fix: export constraints.bzl file from @local_config_platform so it can be used in downstream bzl_library targets

gregmagolan · copybara-github · commit 4959d34e8447 · 2022-11-08T08:25:33.000-08:00
Downstream rule sets may depend on `@local_config_platform//:constraints.bzl` but when they do there is no way easy way to make that load statement compatible with `bzl_library`. This change makes it possible to use `bzl_library` on starlark code that loads from `@local_config_platform//:constraints.bzl`. For example, ``` bzl_library( name = "local_config_platform_constraints", srcs = ["@local_config_platform//:constraints.bzl"], ) bzl_library( name = "platform_utils", srcs = ["//lib/private:platform_utils.bzl"], deps = [":local_config_platform_constraints"], ) ``` Closes bazelbuild#16665. PiperOrigin-RevId: 486957479 Change-Id: I328b7a3722aea95b3151ed88f23c277ed4154202
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/LocalConfigPlatformFunction.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/LocalConfigPlatformFunction.java
@@ -175,7 +175,11 @@ private static String buildFileContent(String repositoryName) {
             "platform(name = 'host',",
             "  # Auto-detected host platform constraints.",
             "  constraint_values = HOST_CONSTRAINTS,",
-            ")"),
+            ")",
+            "exports_files([",
+            "  # Export constraints.bzl for use in downstream bzl_library targets.",
+            "  'constraints.bzl',",
+            "])"),
         repositoryName);
   }
 
