Enable manual trimming of config_feature_flags.

This enables users of config_feature_flags to specify the flags used by the transitive closure of a particular target in the transitive_configs attribute of all targets. It also adds a flag - --enforce_transitive_configs_for_config_feature_flag - which enforces this specification and uses it to trim the set of flags available to that target.

RELNOTES: None.
PiperOrigin-RevId: 196846092

1 files changed, 5 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigRules.java b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigRules.java
index de5e22f779..4d49eafa58 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigRules.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigRules.java
@@ -14,6 +14,7 @@
 package com.google.devtools.build.lib.rules.config;
 
 import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.analysis.BaseRuleClasses;
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider;
 import com.google.devtools.build.lib.analysis.ConfiguredRuleClassProvider.RuleSet;
 import com.google.devtools.build.lib.rules.core.CoreRules;
@@ -30,9 +31,12 @@ public final class ConfigRules implements RuleSet {
 
   @Override
   public void init(ConfiguredRuleClassProvider.Builder builder) {
+    builder.setTrimmingTransitionFactory(
+        new ConfigFeatureFlagTaggedTrimmingTransitionFactory(BaseRuleClasses.TAGGED_TRIMMING_ATTR));
     builder.addRuleDefinition(new ConfigRuleClasses.ConfigBaseRule());
     builder.addRuleDefinition(new ConfigRuleClasses.ConfigSettingRule());
-    builder.addConfig(ConfigFeatureFlagOptions.class, new ConfigFeatureFlagConfiguration.Loader());
+    builder.addConfig(ConfigFeatureFlagOptions.class,
+        new ConfigFeatureFlagConfiguration.Loader());
 
     builder.addRuleDefinition(new ConfigRuleClasses.ConfigFeatureFlagRule());
     builder.addSkylarkAccessibleTopLevels("config_common", new ConfigSkylarkCommon());