From ca27e86a70b3998c79fccbfebd4fb020013c9483 Mon Sep 17 00:00:00 2001
From: Fabian Meumertzheim <fabian@meumertzhe.im>
Date: Sat, 17 Oct 2026 19:32:23 +0200
Subject: [PATCH] Skip transition machinery for `config.none()` attributes

`NoConfigTransition` always yields the empty configuration, so there is
no need to restrict the parent options, run the transition, and go
through `BuildConfigurationKeyProducer` for each dependency edge. Every
rule has a `package_metadata` attribute that uses `config.none()`, so
this applies to each label in `default_package_metadata` for every
configured target.
---
 .../google/devtools/build/lib/analysis/producers/BUILD   | 2 ++
 .../build/lib/analysis/producers/DependencyProducer.java | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/producers/BUILD b/src/main/java/com/google/devtools/build/lib/analysis/producers/BUILD
index 0d475dbbb5a701..0c8cf27f8347d3 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/producers/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/analysis/producers/BUILD
@@ -50,6 +50,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/analysis:transitive_dependency_state",
         "//src/main/java/com/google/devtools/build/lib/analysis/config:build_configuration",
         "//src/main/java/com/google/devtools/build/lib/analysis/config:build_options",
+        "//src/main/java/com/google/devtools/build/lib/analysis/config:common_options",
         "//src/main/java/com/google/devtools/build/lib/analysis/config:config_conditions",
         "//src/main/java/com/google/devtools/build/lib/analysis/config:config_matching_provider",
         "//src/main/java/com/google/devtools/build/lib/analysis/config:configuration_transition_event",
@@ -59,6 +60,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/analysis/config:starlark_transition_cache",
         "//src/main/java/com/google/devtools/build/lib/analysis/config/transitions:composing_transition_factory",
         "//src/main/java/com/google/devtools/build/lib/analysis/config/transitions:configuration_transition",
+        "//src/main/java/com/google/devtools/build/lib/analysis/config/transitions:no_config_transition",
         "//src/main/java/com/google/devtools/build/lib/analysis/config/transitions:patch_transition",
         "//src/main/java/com/google/devtools/build/lib/analysis/config/transitions:transition_collector",
         "//src/main/java/com/google/devtools/build/lib/analysis/config/transitions:transition_factory",
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/producers/DependencyProducer.java b/src/main/java/com/google/devtools/build/lib/analysis/producers/DependencyProducer.java
index 525928a60a80ac..ed611349fb69ba 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/producers/DependencyProducer.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/producers/DependencyProducer.java
@@ -33,9 +33,11 @@
 import com.google.devtools.build.lib.analysis.InvalidVisibilityDependencyException;
 import com.google.devtools.build.lib.analysis.MaterializedDepsInfo;
 import com.google.devtools.build.lib.analysis.config.BuildConfigurationValue;
+import com.google.devtools.build.lib.analysis.config.CommonOptions;
 import com.google.devtools.build.lib.analysis.config.ConfigurationTransitionEvent;
 import com.google.devtools.build.lib.analysis.config.DependencyEvaluationException;
 import com.google.devtools.build.lib.analysis.config.transitions.ConfigurationTransition;
+import com.google.devtools.build.lib.analysis.config.transitions.NoConfigTransition;
 import com.google.devtools.build.lib.analysis.config.transitions.TransitionCollector;
 import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory.TransitionCreationException;
 import com.google.devtools.build.lib.analysis.producers.DependencyMapProducer.MaterializerException;
@@ -215,6 +217,13 @@ public StateMachine step(Tasks tasks) {
       return DONE;
     }
     sink.acceptTransition(kind, toLabel, attributeTransition);
+    if (attributeTransition == NoConfigTransition.INSTANCE) {
+      // The result doesn't depend on the parent configuration, so skip the general machinery.
+      transitionedConfigurations =
+          ImmutableMap.of(
+              PATCH_TRANSITION_KEY, BuildConfigurationKey.create(CommonOptions.EMPTY_OPTIONS));
+      return processTransitionResult(tasks);
+    }
     return new TransitionApplier(
         toLabel,
         configurationKey,