Enforce one aconfig_declaration per aconfig package

Bug: b/319121098
Change-Id: Ibe3f1587ed7754f00f464cf385ce51ee9a142412

aconfig/all_aconfig_declarations.go

@@ -16,6 +16,7 @@ package aconfig
 
 import (
 	"android/soong/android"
+	"fmt"
 )
 
 // A singleton module that collects all of the aconfig flags declared in the
@@ -35,6 +36,7 @@ type allAconfigDeclarationsSingleton struct {
 
 func (this *allAconfigDeclarationsSingleton) GenerateBuildActions(ctx android.SingletonContext) {
 	// Find all of the aconfig_declarations modules
+	var packages = make(map[string]int)
 	var cacheFiles android.Paths
 	ctx.VisitAllModules(func(module android.Module) {
 		decl, ok := android.SingletonModuleProvider(ctx, module, android.AconfigDeclarationsProviderKey)
@@ -42,8 +44,21 @@ func (this *allAconfigDeclarationsSingleton) GenerateBuildActions(ctx android.Si
 			return
 		}
 		cacheFiles = append(cacheFiles, decl.IntermediateCacheOutputPath)
+		packages[decl.Package]++
 	})
 
+	var numOffendingPkg = 0
+	for pkg, cnt := range packages {
+		if cnt > 1 {
+			fmt.Printf("%d aconfig_declarations found for package %s\n", cnt, pkg)
+			numOffendingPkg++
+		}
+	}
+
+	if numOffendingPkg > 0 {
+		panic(fmt.Errorf("Only one aconfig_declarations allowed for each package."))
+	}
+
 	// Generate build action for aconfig
 	this.intermediatePath = android.PathForIntermediates(ctx, "all_aconfig_declarations.pb")
 	ctx.Build(pctx, android.BuildParams{