Extend TemplateExpander to handle $(func param) expansion

Rewrite the Expander to use the new functionality; also rewrite the Skylark
expand_location function to use it.

PiperOrigin-RevId: 173280839

1 files changed, 25 insertions, 6 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleImplementationFunctions.java b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleImplementationFunctions.java
index f71730b10a..53aaf47e79 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleImplementationFunctions.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/skylark/SkylarkRuleImplementationFunctions.java
@@ -20,11 +20,12 @@ import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.AliasProvider;
 import com.google.devtools.build.lib.analysis.CommandHelper;
 import com.google.devtools.build.lib.analysis.FileProvider;
-import com.google.devtools.build.lib.analysis.LocationExpander;
 import com.google.devtools.build.lib.analysis.Runfiles;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.analysis.configuredtargets.AbstractConfiguredTarget;
+import com.google.devtools.build.lib.analysis.stringtemplate.ExpansionException;
+import com.google.devtools.build.lib.analysis.stringtemplate.TemplateContext;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.skylarkinterface.Param;
@@ -318,11 +319,12 @@ public class SkylarkRuleImplementationFunctions {
             throws EvalException {
           ctx.checkMutable("expand_location");
           try {
-            return new LocationExpander(
-                    ctx.getRuleContext(),
-                    makeLabelMap(targets.getContents(TransitiveInfoCollection.class, "targets")),
-                    LocationExpander.Options.EXEC_PATHS)
-                .expand(input);
+            return ctx
+                .getRuleContext()
+                .getExpander(new FakeTemplateContext())
+                .withExecLocations(
+                    makeLabelMap(targets.getContents(TransitiveInfoCollection.class, "targets")))
+                .expand(/*attributeName=*/null, input);
           } catch (IllegalStateException ise) {
             throw new EvalException(loc, ise);
           }
@@ -330,6 +332,23 @@ public class SkylarkRuleImplementationFunctions {
       };
 
   /**
+   * This class only exists for backwards compatibility. Previously, we were using LocationExpander
+   * directly, which passes through all unrecognized $() expressions.
+   */
+  private static final class FakeTemplateContext implements TemplateContext {
+    @Override
+    public String lookupVariable(String name) throws ExpansionException {
+      return String.format("$$(%s)", name);
+    }
+
+    @Override
+    public String lookupFunction(String name, String param) throws ExpansionException {
+      // Variables get recursively expanded, functions don't.
+      return String.format("$(%s %s)", name, param);
+    }
+  }
+
+  /**
    * Builds a map: Label -> List of files from the given labels
    *
    * @param knownLabels List of known labels