prebuilt_apex created ApexInfo must not include prebuilt_ prefix

As part of the work to modularize the hiddenAPI processing the
generation of the monolithic hidden API index file needs to be moved
to the platform_bootclasspath module type. Doing that broke the
TestBootDexJarsFromSourcesAndPrebuilts tests which checks the inputs to
the rule that creates that file. Fixing that required added a
platform_bootclasspath module to the test fixture for those tests which
highlighted an issue with the prebuilt_apex module.

Previously, when the prebuilt_apex created apex variants it would use
its own name as the apex variant name, even when that name included the
prebuilt_ prefix. That broke the platform_bootclasspath logic as it was
looking for apex variants for "myapex" but the only ones available were
"prebuilt_myapex".

This change ensures that it always uses the unprefixed name and fixes
the TestNoUpdatableJarsInBootImage to match. This also adds some
improved error reporting in platform_bootclasspath which helped debug
this problem.

Bug: 177892522
Test: m nothing
Change-Id: I3e88b5cec767f77dcc0e94b3ae38b499d07eadf0

1 files changed, 24 insertions, 1 deletions

diff --git a/java/platform_bootclasspath.go b/java/platform_bootclasspath.go
index d98ce6719..d70098080 100644
--- a/java/platform_bootclasspath.go
+++ b/java/platform_bootclasspath.go
@@ -208,7 +208,30 @@ func addDependencyOntoApexModulePair(ctx android.BottomUpMutatorContext, apex st
 	// error, unless missing dependencies are allowed. The simplest way to handle that is to add a
 	// dependency that will not be satisfied and the default behavior will handle it.
 	if !addedDep {
-		ctx.AddFarVariationDependencies(variations, tag, name)
+		// Add dependency on the unprefixed (i.e. source or renamed prebuilt) module which we know does
+		// not exist. The resulting error message will contain useful information about the available
+		// variants.
+		reportMissingVariationDependency(ctx, variations, name)
+
+		// Add dependency on the missing prefixed prebuilt variant too if a module with that name exists
+		// so that information about its available variants will be reported too.
+		if ctx.OtherModuleExists(prebuiltName) {
+			reportMissingVariationDependency(ctx, variations, prebuiltName)
+		}
+	}
+}
+
+// reportMissingVariationDependency intentionally adds a dependency on a missing variation in order
+// to generate an appropriate error message with information about the available variations.
+func reportMissingVariationDependency(ctx android.BottomUpMutatorContext, variations []blueprint.Variation, name string) {
+	modules := ctx.AddFarVariationDependencies(variations, nil, name)
+	if len(modules) != 1 {
+		panic(fmt.Errorf("Internal Error: expected one module, found %d", len(modules)))
+		return
+	}
+	if modules[0] != nil {
+		panic(fmt.Errorf("Internal Error: expected module to be missing but was found: %q", modules[0]))
+		return
 	}
 }