From b5f6d9ea511a6515637de0c4aaaf3859061f07cb Mon Sep 17 00:00:00 2001
From: Alix <agespino@google.com>
Date: Wed, 20 Apr 2022 23:00:58 +0000
Subject: [PATCH] Deprecating clang Property

Clang has defaulted to true since 2018. Clang property is deprecated.
Set up a BUILD_BROKEN_CLANG_PROPERTY flag so partners can bypass \
errors from using clang.

Bug: 208980553
Test: m nothing & treehugger
Change-Id: I8fd7d3e6bdbb963279248d3482e8a590238727e3
---
 android/config.go   |  4 ++++
 android/variable.go |  1 +
 cc/cc.go            |  2 ++
 cc/cc_test.go       | 50 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/android/config.go b/android/config.go
index 5ca94209f..6654b499c 100644
--- a/android/config.go
+++ b/android/config.go
@@ -1630,6 +1630,10 @@ func (c *deviceConfig) ShippingApiLevel() ApiLevel {
 	return uncheckedFinalApiLevel(apiLevel)
 }
 
+func (c *deviceConfig) BuildBrokenClangProperty() bool {
+	return c.config.productVariables.BuildBrokenClangProperty
+}
+
 func (c *deviceConfig) BuildBrokenEnforceSyspropOwner() bool {
 	return c.config.productVariables.BuildBrokenEnforceSyspropOwner
 }
diff --git a/android/variable.go b/android/variable.go
index 2d7b0bf8e..7a080fef7 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -430,6 +430,7 @@ type productVariables struct {
 
 	ShippingApiLevel *string `json:",omitempty"`
 
+	BuildBrokenClangProperty           bool     `json:",omitempty"`
 	BuildBrokenDepfile                 *bool    `json:",omitempty"`
 	BuildBrokenEnforceSyspropOwner     bool     `json:",omitempty"`
 	BuildBrokenTrebleSyspropNeverallow bool     `json:",omitempty"`
diff --git a/cc/cc.go b/cc/cc.go
index 336771a83..f1e9bf621 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -1900,6 +1900,8 @@ func (c *Module) GenerateAndroidBuildActions(actx android.ModuleContext) {
 
 	if c.Properties.Clang != nil && *c.Properties.Clang == false {
 		ctx.PropertyErrorf("clang", "false (GCC) is no longer supported")
+	} else if c.Properties.Clang != nil && !ctx.DeviceConfig().BuildBrokenClangProperty() {
+		ctx.PropertyErrorf("clang", "property is deprecated, see Changes.md file")
 	}
 
 	flags := Flags{
diff --git a/cc/cc_test.go b/cc/cc_test.go
index f02570020..36174d639 100644
--- a/cc/cc_test.go
+++ b/cc/cc_test.go
@@ -4336,3 +4336,53 @@ func TestIncludeDirectoryOrdering(t *testing.T) {
 	}
 
 }
+
+func TestCcBuildBrokenClangProperty(t *testing.T) {
+	tests := []struct {
+		name                     string
+		clang                    bool
+		BuildBrokenClangProperty bool
+		err                      string
+	}{
+		{
+			name:  "error when clang is set to false",
+			clang: false,
+			err:   "is no longer supported",
+		},
+		{
+			name:  "error when clang is set to true",
+			clang: true,
+			err:   "property is deprecated, see Changes.md",
+		},
+		{
+			name:                     "no error when BuildBrokenClangProperty is explicitly set to true",
+			clang:                    true,
+			BuildBrokenClangProperty: true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			bp := fmt.Sprintf(`
+			cc_library {
+			   name: "foo",
+			   clang: %t,
+			}`, test.clang)
+
+			if test.err == "" {
+				android.GroupFixturePreparers(
+					prepareForCcTest,
+					android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+						if test.BuildBrokenClangProperty {
+							variables.BuildBrokenClangProperty = test.BuildBrokenClangProperty
+						}
+					}),
+				).RunTestWithBp(t, bp)
+			} else {
+				prepareForCcTest.
+					ExtendWithErrorHandler(android.FixtureExpectsOneErrorPattern(test.err)).
+					RunTestWithBp(t, bp)
+			}
+		})
+	}
+}