Add dependency to list of asset files

We had a dependency on each file in the asset directories, but that
wouldn't cause aapt2 to run if a file was removed.  Add a dependency
on a file that contains the list of files in the asset directories.

Fixes: 172867096
Test: m CarrierConfig && rm packages/apps/CarrierConfig/assets/carrier_config_no_sim.xml && m CarrierConfig
Change-Id: I35f3b85355fa890a3e95eaa6458a21466b6930e4

android/defs.go

@@ -20,7 +20,7 @@ import (
 	"testing"
 
 	"github.com/google/blueprint"
-	_ "github.com/google/blueprint/bootstrap"
+	"github.com/google/blueprint/bootstrap"
 	"github.com/google/blueprint/proptools"
 )
 
@@ -200,3 +200,8 @@ func ContentFromFileRuleForTests(t *testing.T, params TestingBuildParams) string
 
 	return content
 }
+
+// GlobToListFileRule creates a rule that writes a list of files matching a pattern to a file.
+func GlobToListFileRule(ctx ModuleContext, pattern string, excludes []string, file WritablePath) {
+	bootstrap.GlobFile(ctx.blueprintModuleContext(), pattern, excludes, file.String())
+}

android/module.go

@@ -331,6 +331,8 @@ type BaseContext interface {
 type ModuleContext interface {
 	BaseModuleContext
 
+	blueprintModuleContext() blueprint.ModuleContext
+
 	// Deprecated: use ModuleContext.Build instead.
 	ModuleBuild(pctx PackageContext, params ModuleBuildParams)
 
@@ -2544,6 +2546,10 @@ func (m *moduleContext) CheckbuildFile(srcPath Path) {
 	m.checkbuildFiles = append(m.checkbuildFiles, srcPath)
 }
 
+func (m *moduleContext) blueprintModuleContext() blueprint.ModuleContext {
+	return m.bp
+}
+
 // SrcIsModule decodes module references in the format ":name" into the module name, or empty string if the input
 // was not a module reference.
 func SrcIsModule(s string) (module string) {

java/aar.go

@@ -17,6 +17,7 @@ package java
 import (
 	"fmt"
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"android/soong/android"
@@ -192,22 +193,31 @@ func (a *aapt) aapt2Flags(ctx android.ModuleContext, sdkContext sdkContext,
 		rroDirs = append(rroDirs, resRRODirs...)
 	}
 
-	var assetFiles android.Paths
-	for _, dir := range assetDirs {
-		assetFiles = append(assetFiles, androidResourceGlob(ctx, dir)...)
+	var assetDeps android.Paths
+	for i, dir := range assetDirs {
+		// Add a dependency on every file in the asset directory.  This ensures the aapt2
+		// rule will be rerun if one of the files in the asset directory is modified.
+		assetDeps = append(assetDeps, androidResourceGlob(ctx, dir)...)
+
+		// Add a dependency on a file that contains a list of all the files in the asset directory.
+		// This ensures the aapt2 rule will be run if a file is removed from the asset directory,
+		// or a file is added whose timestamp is older than the output of aapt2.
+		assetFileListFile := android.PathForModuleOut(ctx, "asset_dir_globs", strconv.Itoa(i)+".glob")
+		androidResourceGlobList(ctx, dir, assetFileListFile)
+		assetDeps = append(assetDeps, assetFileListFile)
 	}
 
 	assetDirStrings := assetDirs.Strings()
 	if a.noticeFile.Valid() {
 		assetDirStrings = append(assetDirStrings, filepath.Dir(a.noticeFile.Path().String()))
-		assetFiles = append(assetFiles, a.noticeFile.Path())
+		assetDeps = append(assetDeps, a.noticeFile.Path())
 	}
 
 	linkFlags = append(linkFlags, "--manifest "+manifestPath.String())
 	linkDeps = append(linkDeps, manifestPath)
 
 	linkFlags = append(linkFlags, android.JoinWithPrefix(assetDirStrings, "-A "))
-	linkDeps = append(linkDeps, assetFiles...)
+	linkDeps = append(linkDeps, assetDeps...)
 
 	// SDK version flags
 	minSdkVersion, err := sdkContext.minSdkVersion().effectiveVersionString(ctx)

java/android_resources.go

@@ -38,10 +38,21 @@ var androidResourceIgnoreFilenames = []string{
 	"*~",
 }
 
+// androidResourceGlob returns the list of files in the given directory, using the standard
+// exclusion patterns for Android resources.
 func androidResourceGlob(ctx android.ModuleContext, dir android.Path) android.Paths {
 	return ctx.GlobFiles(filepath.Join(dir.String(), "**/*"), androidResourceIgnoreFilenames)
 }
 
+// androidResourceGlobList creates a rule to write the list of files in the given directory, using
+// the standard exclusion patterns for Android resources, to the given output file.
+func androidResourceGlobList(ctx android.ModuleContext, dir android.Path,
+	fileListFile android.WritablePath) {
+
+	android.GlobToListFileRule(ctx, filepath.Join(dir.String(), "**/*"),
+		androidResourceIgnoreFilenames, fileListFile)
+}
+
 type overlayType int
 
 const (