Fix ConfigFeatureFlagTransitionFactory to obey PatchTransition equality.

This requirement was added to PatchTransition in commit e6392cd380fce14d719890c78d5eb2657e8a6cfc.
This also adds tests for ConfigFeatureFlagTransitionFactory's other
behaviors.

RELNOTES: None.
PiperOrigin-RevId: 158294134

1 files changed, 37 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagTransitionFactory.java b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagTransitionFactory.java
index 8f7ab87954..757ca9e2a5 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagTransitionFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/config/ConfigFeatureFlagTransitionFactory.java
@@ -36,13 +36,18 @@ public class ConfigFeatureFlagTransitionFactory implements RuleTransitionFactory
   /** Transition which resets the set of flag-value pairs to the map it was constructed with. */
   private static final class ConfigFeatureFlagValuesTransition implements PatchTransition {
     private final ImmutableSortedMap<Label, String> flagValues;
+    private final int cachedHashCode;
 
     public ConfigFeatureFlagValuesTransition(Map<Label, String> flagValues) {
       this.flagValues = ImmutableSortedMap.copyOf(flagValues);
+      this.cachedHashCode = this.flagValues.hashCode();
     }
 
     @Override
     public BuildOptions apply(BuildOptions options) {
+      if (!options.contains(ConfigFeatureFlagConfiguration.Options.class)) {
+        return options;
+      }
       BuildOptions result = options.clone();
       result.get(ConfigFeatureFlagConfiguration.Options.class).replaceFlagValues(flagValues);
       return result;
@@ -52,6 +57,22 @@ public class ConfigFeatureFlagTransitionFactory implements RuleTransitionFactory
     public boolean defaultsToSelf() {
       throw new UnsupportedOperationException("supported in dynamic mode only");
     }
+
+    @Override
+    public boolean equals(Object other) {
+      return other instanceof ConfigFeatureFlagValuesTransition
+          && this.flagValues.equals(((ConfigFeatureFlagValuesTransition) other).flagValues);
+    }
+
+    @Override
+    public int hashCode() {
+      return cachedHashCode;
+    }
+
+    @Override
+    public String toString() {
+      return String.format("ConfigFeatureFlagValuesTransition{flagValues=%s}", flagValues);
+    }
   }
 
   private final String attributeName;
@@ -72,4 +93,20 @@ public class ConfigFeatureFlagTransitionFactory implements RuleTransitionFactory
     return new ConfigFeatureFlagValuesTransition(
         NonconfigurableAttributeMapper.of(rule).get(attributeName, LABEL_KEYED_STRING_DICT));
   }
+
+  @Override
+  public boolean equals(Object other) {
+    return other instanceof ConfigFeatureFlagTransitionFactory
+        && this.attributeName.equals(((ConfigFeatureFlagTransitionFactory) other).attributeName);
+  }
+
+  @Override
+  public int hashCode() {
+    return attributeName.hashCode();
+  }
+
+  @Override
+  public String toString() {
+    return String.format("ConfigFeatureFlagTransitionFactory{attributeName=%s}", attributeName);
+  }
 }