Track allowed transitive deps in any updatable module.

Instead of tracking per module and per module variant, track allowed
list of dependecies for all modules combined. This avoids issues with
different products and different downstream branches having different
build graphs.

To compare allowed_deps.txt vs head, run:
:; m -j out/soong/apex/depsinfo/new-allowed-deps.txt.check

To update source allowed_deps.txt, run:
:; build/soong/scripts/update-apex-allowed-deps.sh

Bug: 149622332
Test: m
Change-Id: I56771ba3fea748de8e9c58c80758670572f7af53
Merged-In: Ic518fbd9ebfe1b46aaf9a58df731780a7e5a676b

1 files changed, 57 insertions, 17 deletions

diff --git a/apex/apex_singleton.go b/apex/apex_singleton.go
index 83a56a2b5..afb739cef 100644
--- a/apex/apex_singleton.go
+++ b/apex/apex_singleton.go
@@ -17,9 +17,9 @@
 package apex
 
 import (
-	"github.com/google/blueprint"
-
 	"android/soong/android"
+
+	"github.com/google/blueprint"
 )
 
 func init() {
@@ -27,39 +27,79 @@ func init() {
 }
 
 type apexDepsInfoSingleton struct {
-	// Output file with all flatlists from updatable modules' deps-info combined
-	updatableFlatListsPath android.OutputPath
+	allowedApexDepsInfoCheckResult android.OutputPath
 }
 
 func apexDepsInfoSingletonFactory() android.Singleton {
 	return &apexDepsInfoSingleton{}
 }
 
-var combineFilesRule = pctx.AndroidStaticRule("combineFilesRule",
-	blueprint.RuleParams{
-		Command:        "cat $out.rsp | xargs cat > $out",
+var (
+	// Generate new apex allowed_deps.txt by merging all internal dependencies.
+	generateApexDepsInfoFilesRule = pctx.AndroidStaticRule("generateApexDepsInfoFilesRule", blueprint.RuleParams{
+		Command: "cat $out.rsp | xargs cat" +
+			// Only track non-external dependencies, i.e. those that end up in the binary
+			" | grep -v '(external)'" +
+			// Ignore comments in any of the files
+			" | grep -v '^#'" +
+			" | sort -u -f >$out",
 		Rspfile:        "$out.rsp",
 		RspfileContent: "$in",
-	},
+	})
+
+	// Diff two given lists while ignoring comments in the allowed deps file.
+	diffAllowedApexDepsInfoRule = pctx.AndroidStaticRule("diffAllowedApexDepsInfoRule", blueprint.RuleParams{
+		Description: "Diff ${allowed_deps} and ${new_allowed_deps}",
+		Command: `
+			if grep -v '^#' ${allowed_deps} | diff -B - ${new_allowed_deps}; then
+			   touch ${out};
+			else
+				echo -e "\n******************************";
+				echo "ERROR: go/apex-allowed-deps-error";
+				echo "******************************";
+				echo "Detected changes to allowed dependencies in updatable modules.";
+				echo "To fix and update build/soong/apex/allowed_deps.txt, please run:";
+				echo "$$ (croot && build/soong/scripts/update-apex-allowed-deps.sh)";
+				echo "Members of mainline-modularization@google.com will review the changes.";
+				echo -e "******************************\n";
+				exit 1;
+			fi;
+		`,
+	}, "allowed_deps", "new_allowed_deps")
 )
 
 func (s *apexDepsInfoSingleton) GenerateBuildActions(ctx android.SingletonContext) {
 	updatableFlatLists := android.Paths{}
 	ctx.VisitAllModules(func(module android.Module) {
 		if binaryInfo, ok := module.(android.ApexBundleDepsInfoIntf); ok {
-			if path := binaryInfo.FlatListPath(); path != nil {
-				if binaryInfo.Updatable() {
-					updatableFlatLists = append(updatableFlatLists, path)
-				}
+			if path := binaryInfo.FlatListPath(); path != nil && binaryInfo.Updatable() {
+				updatableFlatLists = append(updatableFlatLists, path)
 			}
 		}
 	})
 
-	s.updatableFlatListsPath = android.PathForOutput(ctx, "apex", "depsinfo", "updatable-flatlists.txt")
+	allowedDeps := android.ExistentPathForSource(ctx, "build/soong/apex/allowed_deps.txt").Path()
+
+	newAllowedDeps := android.PathForOutput(ctx, "apex", "depsinfo", "new-allowed-deps.txt")
+	ctx.Build(pctx, android.BuildParams{
+		Rule:   generateApexDepsInfoFilesRule,
+		Inputs: append(updatableFlatLists, allowedDeps),
+		Output: newAllowedDeps,
+	})
+
+	s.allowedApexDepsInfoCheckResult = android.PathForOutput(ctx, newAllowedDeps.Rel()+".check")
 	ctx.Build(pctx, android.BuildParams{
-		Rule:        combineFilesRule,
-		Description: "Generate " + s.updatableFlatListsPath.String(),
-		Inputs:      updatableFlatLists,
-		Output:      s.updatableFlatListsPath,
+		Rule:   diffAllowedApexDepsInfoRule,
+		Input:  newAllowedDeps,
+		Output: s.allowedApexDepsInfoCheckResult,
+		Args: map[string]string{
+			"allowed_deps":     allowedDeps.String(),
+			"new_allowed_deps": newAllowedDeps.String(),
+		},
 	})
 }
+
+func (s *apexDepsInfoSingleton) MakeVars(ctx android.MakeVarsContext) {
+	// Export check result to Make. The path is added to droidcore.
+	ctx.Strict("APEX_ALLOWED_DEPS_CHECK", s.allowedApexDepsInfoCheckResult.String())
+}