--experimental_propagate_custom_flag: support /...-style target p…

…atterns.

This reduces bloat from having to set this flag X times for X flags in a
project. This is especially relevant for projects with multiple versions
simultaneously in the repo.

Eventually we should be able to remove these lists in preference for directly
declaring scope on flag definitions:
#22997.

PiperOrigin-RevId: 694252707
Change-Id: If22d7f8c1fabc5119e7233c321256fa3d84c7fa2

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

@@ -175,11 +175,7 @@ private static BuildOptions maybeGetExecDefaults(
       ImmutableMap<Label, Object> starlarkOptions =
           fromOptions.getStarlarkOptions().entrySet().stream()
               .filter(
-                  (starlarkFlag) ->
-                      fromOptions
-                          .get(CoreOptions.class)
-                          .customFlagsToPropagate
-                          .contains(starlarkFlag.getKey().toString()))
+                  (starlarkFlag) -> propagateStarlarkFlagToExec(starlarkFlag.getKey(), fromOptions))
               .collect(toImmutableMap(Map.Entry::getKey, (e) -> e.getValue()));
       defaultBuilder.addStarlarkOptions(starlarkOptions);
     } else {
@@ -213,6 +209,23 @@ private static BuildOptions maybeGetExecDefaults(
     return ans;
   }
 
+  /**
+   * Returns true if the given Starlark flag should propagate from the target to exec configuration.
+   */
+  private static boolean propagateStarlarkFlagToExec(
+      Label starlarkFlag, BuildOptions buildOptions) {
+    return buildOptions.get(CoreOptions.class).customFlagsToPropagate.stream()
+        .anyMatch(
+            flagToPropagate ->
+                (flagToPropagate.equals(starlarkFlag.toString())
+                    || (flagToPropagate.endsWith("/...")
+                        && starlarkFlag
+                            .toString()
+                            .startsWith(
+                                flagToPropagate.substring(
+                                    0, flagToPropagate.lastIndexOf("/..."))))));
+  }
+
   /**
    * If the transition changes --cpu but not --platforms, clear out --platforms.
    *

src/test/java/com/google/devtools/build/lib/analysis/config/BuildConfigurationValueTest.java

@@ -27,6 +27,7 @@
 import com.google.devtools.build.lib.skyframe.serialization.testutils.SerializationTester;
 import com.google.devtools.build.lib.vfs.FileSystem;
 import com.google.devtools.common.options.Options;
+import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -337,6 +338,57 @@ def _impl(ctx):
         .isNull();
   }
 
+  @Test
+  // TODO: b/377959266 - fix test setup bug that fails Bazel CI. This test's logic doesn't cause the
+  //   bug: it's somehow caused by test naming. See bug for details.
+  @Ignore("b/377959266")
+  public void testExecStarlarkFlag_isPropagatedByTargetPattern() throws Exception {
+    scratch.file(
+        "my_starlark_flag/rule_defs.bzl",
+        """
+        bool_flag = rule(
+            implementation = lambda ctx: [],
+            build_setting = config.bool(flag = True),
+        )
+        """);
+    scratch.file(
+        "flags_to_propagate/BUILD",
+        """
+        load("//my_starlark_flag:rule_defs.bzl", "bool_flag")
+        bool_flag(
+            name = "include_me",
+            build_setting_default = "False",
+        )
+        """);
+    scratch.file(
+        "flags_to_reset/BUILD",
+        """
+        load("//my_starlark_flag:rule_defs.bzl", "bool_flag")
+        bool_flag(
+            name = "exclude_me",
+            build_setting_default = "False",
+        )
+        """);
+
+    BuildConfigurationValue cfg =
+        createExec(
+            ImmutableMap.of(
+                "//flags_to_propagate:include_me", "true", "//flags_to_reset:exclude_me", "true"),
+            "--experimental_exclude_starlark_flags_from_exec_config=true",
+            "--experimental_propagate_custom_flag=//flags_to_propagate/...");
+
+    assertThat(
+            cfg.getOptions()
+                .getStarlarkOptions()
+                .get(Label.parseCanonicalUnchecked("//flags_to_propagate:include_me")))
+        .isEqualTo("true");
+    assertThat(
+            cfg.getOptions()
+                .getStarlarkOptions()
+                .get(Label.parseCanonicalUnchecked("//flags_to_reset:exclude_me")))
+        .isNull();
+  }
+
   @Test
   public void testHostCompilationModeDefault() throws Exception {
     BuildConfigurationValue cfg = createExec();