From f3ccfa9b9936b577bad8b40c363b5e0795ad615c Mon Sep 17 00:00:00 2001
From: Jeff Gaston <jeffrygaston@google.com>
Date: Wed, 23 Aug 2017 17:03:42 -0700
Subject: [PATCH] Fix crash when running androidmk against
 frameworks/base/Android.mk

The was a variable on the right-hand side of the assignment to
LOCAL_MODULE_CLASS , which wants a non-nil scope

Bug: 64266643
Test: androidmk frameworks/base/Android.mk
Test: androidmk prebuilts/misc/common/ddmlib/Android.mk

Change-Id: I52d33f5e5cb1179f84d4df149ef804268d67f7fb
---
 androidmk/cmd/androidmk/android.go | 2 +-
 androidmk/parser/scope.go          | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/androidmk/cmd/androidmk/android.go b/androidmk/cmd/androidmk/android.go
index f853716a9..19ed4ecf2 100644
--- a/androidmk/cmd/androidmk/android.go
+++ b/androidmk/cmd/androidmk/android.go
@@ -449,7 +449,7 @@ func sanitize(sub string) func(ctx variableAssignmentContext) error {
 }
 
 func prebuiltClass(ctx variableAssignmentContext) error {
-	class := ctx.mkvalue.Value(nil)
+	class := ctx.mkvalue.Value(ctx.file.scope)
 	if v, ok := prebuiltTypes[class]; ok {
 		ctx.file.scope.Set("BUILD_PREBUILT", v)
 	} else {
diff --git a/androidmk/parser/scope.go b/androidmk/parser/scope.go
index 5e94ea583..60efac275 100644
--- a/androidmk/parser/scope.go
+++ b/androidmk/parser/scope.go
@@ -1,6 +1,8 @@
 package parser
 
-import "strings"
+import (
+	"strings"
+)
 
 type Scope interface {
 	Get(name string) string
@@ -84,6 +86,9 @@ func (v Variable) Value(scope Scope) string {
 	if ret, ok := v.EvalFunction(scope); ok {
 		return ret
 	}
+	if scope == nil {
+		panic("Cannot take the value of a variable in a nil scope")
+	}
 	return scope.Get(v.Name.Value(scope))
 }