bpfix: Remove local_include_dirs if we remove the last entry

This still leaves a blank line in it's place, but that's a more general
problem.

Test: m blueprint_tools
Test: Run bpfix over AOSP, diff.
Change-Id: I55c1d1c183cfa49beeca07abd539348bc2524c5a

bpfix/bpfix/bpfix.go

@@ -389,7 +389,7 @@ func (f *Fixer) removeMatchingModuleListProperties(canonicalName string, legacyN
 			continue
 		}
 		legacyList, ok := getLiteralListProperty(mod, legacyName)
-		if !ok {
+		if !ok || len(legacyList.Values) == 0 {
 			continue
 		}
 		canonicalList, ok := getLiteralListProperty(mod, canonicalName)
@@ -397,6 +397,10 @@ func (f *Fixer) removeMatchingModuleListProperties(canonicalName string, legacyN
 			continue
 		}
 		filterExpressionList(legacyList, canonicalList)
+
+		if len(legacyList.Values) == 0 {
+			removeProperty(mod, legacyName)
+		}
 	}
 	return nil
 }

bpfix/bpfix/bpfix_test.go

@@ -73,20 +73,24 @@ func implFilterListTest(t *testing.T, local_include_dirs []string, export_includ
 
 	// lookup legacy property
 	mod := fixer.tree.Defs[0].(*parser.Module)
-	_, found := mod.GetProperty("local_include_dirs")
-	if !found {
-		t.Fatalf("failed to include key local_include_dirs in parse tree")
+
+	expectedResultString := fmt.Sprintf("%q", expectedResult)
+	if expectedResult == nil {
+		expectedResultString = "unset"
 	}
 
 	// check that the value for the legacy property was updated to the correct value
 	errorHeader := fmt.Sprintf("\nFailed to correctly simplify key 'local_include_dirs' in the presence of 'export_include_dirs.'\n"+
 		"original local_include_dirs: %q\n"+
 		"original export_include_dirs: %q\n"+
-		"expected result: %q\n"+
+		"expected result: %s\n"+
 		"actual result: ",
-		local_include_dirs, export_include_dirs, expectedResult)
-	result, ok := mod.GetProperty("local_include_dirs")
-	if !ok {
+		local_include_dirs, export_include_dirs, expectedResultString)
+	result, found := mod.GetProperty("local_include_dirs")
+	if !found {
+		if expectedResult == nil {
+			return
+		}
 		t.Fatal(errorHeader + "property not found")
 	}
 
@@ -95,6 +99,10 @@ func implFilterListTest(t *testing.T, local_include_dirs []string, export_includ
 		t.Fatalf("%sproperty is not a list: %v", errorHeader, listResult)
 	}
 
+	if expectedResult == nil {
+		t.Fatalf("%sproperty exists: %v", errorHeader, listResult)
+	}
+
 	actualExpressions := listResult.Values
 	actualValues := make([]string, 0)
 	for _, expr := range actualExpressions {
@@ -109,7 +117,7 @@ func implFilterListTest(t *testing.T, local_include_dirs []string, export_includ
 
 func TestSimplifyKnownVariablesDuplicatingEachOther(t *testing.T) {
 	// TODO use []Expression{} once buildTree above can support it (which is after b/38325146 is done)
-	implFilterListTest(t, []string{"include"}, []string{"include"}, []string{})
+	implFilterListTest(t, []string{"include"}, []string{"include"}, nil)
 	implFilterListTest(t, []string{"include1"}, []string{"include2"}, []string{"include1"})
 	implFilterListTest(t, []string{"include1", "include2", "include3", "include4"}, []string{"include2"},
 		[]string{"include1", "include3", "include4"})