Clean up DependencyResolver's interface for the dynamic config migration and for general readability.
Major changes:
- Remove the intermediate Attribute -> LabelAndConfiguration multimap (computed in resolveAttributes). Instead, feed discovered values directly into the final Attribute -> Dependency map via a new RuleResolver interface.
- Remove all references to LabelAndConfiguration. The configuration is always the owning rule's configuration except for two special cases: late-bound attributes with splits and late-bound attributes with LateBoundDefault.useHostConfiguration. The original interface made this very unclear and required a lot of awkward and sometimes incorrect logic. The new interface only involves configurations for the cases that actually need them.
- Remove an ugly hack caused by BuildConfiguration.evaluateTransition mixing poorly with LateBoundDefault.useHostConfiguration (https://github.com/bazelbuild/bazel/blo[]e172693c27f3efc95ed163e43a9f0a7a6fb4017/src/main/java/com/google/devtools/build/lib/analysis/DependencyResolver.java#L488).
- Remove a hack that applies split transitions twice because of BuildConfiguration.evaluateTransition mixing poorly with late-bound split attributes (https://github.com/bazelbuild/bazel/blo[]e172693c27f3efc95ed163e43a9f0a7a6fb4017/src/main/java/com/google/devtools/build/lib/analysis/DependencyResolver.java#L319). This happens to be innocent now but won't be when nested splits are possible.
- Solidifies the API contract for Attribute.LateBoundDefault.useHostConfiguration.
- Applies clearer naming and more consistent ordering to method parameters.
- Better documentation.
This is all also prep work for dynamic split transitions.
tl;dr: late-bound attributes are legitimately special. Treat them that way to make the rest of DependencyResolver cleaner and hack-free.
--
MOS_MIGRATED_REVID=128582618
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Attribute.java b/src/main/java/com/google/devtools/build/lib/packages/Attribute.java
index 5277aef..2ac4851 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Attribute.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Attribute.java
@@ -1090,8 +1090,12 @@
*/
public interface LateBoundDefault<T> {
/**
- * Whether to look up the label in the host configuration. This is only here for the host JDK -
- * we usually need to look up labels in the target configuration.
+ * Whether to look up the label in the host configuration. This is only here for host
+ * compilation tools - we usually need to look up labels in the target configuration.
+ *
+ * <p>This method only sets the configuration passed to {@link #resolve}. If you want the
+ * dependency to also be analyzed in the host configuration, use
+ * {@link ConfigurationTransition#HOST}.
*/
boolean useHostConfiguration();
