Have ConfiguredTargetFactory subclasses declare which FragmentOptions

they need to create their fragments.

This is prerequisite work for fragment-limited configurations
(configurations that only include the fragments needed by their rules'
 transitive closures). Given a set of desired fragment classes, we need
to know which FragmentOptions are needed to instantiate those fragments.

Note that we can't map this relationship the other way (given a set
of FragmentOptions, which fragment classes do they load?). That's
because different fragment loaders may consume overlapping options.
A good example is CppOptions, which is, e.g., used by both the C++
and Python configuration loaders.

At some point, we're probably going to want to force configuration
loaders to only understand options from their own "domain" (or have
well-defined hierarchies). But that's not the reality of today.

--
MOS_MIGRATED_REVID=94091093

1 files changed, 7 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/python/PythonConfigurationLoader.java b/src/main/java/com/google/devtools/build/lib/rules/python/PythonConfigurationLoader.java
index 2acfe17981..79e26b2708 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/python/PythonConfigurationLoader.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/python/PythonConfigurationLoader.java
@@ -14,10 +14,12 @@
 package com.google.devtools.build.lib.rules.python;
 
 import com.google.common.base.Function;
+import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Fragment;
 import com.google.devtools.build.lib.analysis.config.BuildOptions;
 import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
 import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
+import com.google.devtools.build.lib.analysis.config.FragmentOptions;
 import com.google.devtools.build.lib.analysis.config.InvalidConfigurationException;
 import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
 import com.google.devtools.build.lib.rules.cpp.CppOptions;
@@ -37,6 +39,11 @@ public class PythonConfigurationLoader implements ConfigurationFragmentFactory {
     this.cpuTransformer = cpuTransformer;
   }
 
+  @Override
+  public ImmutableSet<Class<? extends FragmentOptions>> requiredOptions() {
+    return ImmutableSet.of(PythonOptions.class, CppOptions.class);
+  }
+
   @Nullable
   private CrosstoolConfig.CToolchain getToolchain(
       ConfigurationEnvironment env, BuildOptions buildOptions, Label crosstoolTop)