From fc57d40bf1545160557bc613d296f44c910c1159 Mon Sep 17 00:00:00 2001
From: Cole Faust <colefaust@google.com>
Date: Thu, 11 Apr 2024 12:09:44 -0700
Subject: [PATCH] Change the syntax for arch selecting and add os selecting

This changes the syntax from select(variant("arch"), {...}) to
select(arch(), {...}) to make it shorter and to make it clear that
we can restrict what variants you can select on.

Bug: 323382414
Test: m nothing --no-skip-soong-tests
Change-Id: Iafe05b5f455895313a563ed6292f4016b58180b0
---
 android/module.go       | 29 ++++++++++++++++++-----------
 android/selects_test.go | 20 ++++++++++++++++++--
 2 files changed, 36 insertions(+), 13 deletions(-)

diff --git a/android/module.go b/android/module.go
index 47bc8295e..26261cca5 100644
--- a/android/module.go
+++ b/android/module.go
@@ -2169,20 +2169,27 @@ func (e configurationEvalutor) EvaluateConfiguration(condition proptools.Configu
 			}
 		}
 		return proptools.ConfigurableValueUndefined()
-	case "variant":
-		if len(condition.Args) != 1 {
-			ctx.OtherModulePropertyErrorf(m, property, "variant requires 1 argument, found %d", len(condition.Args))
+	case "arch":
+		if len(condition.Args) != 0 {
+			ctx.OtherModulePropertyErrorf(m, property, "arch requires no arguments, found %d", len(condition.Args))
 			return proptools.ConfigurableValueUndefined()
 		}
-		if condition.Args[0] == "arch" {
-			if !m.base().ArchReady() {
-				ctx.OtherModulePropertyErrorf(m, property, "A select on arch was attempted before the arch mutator ran")
-				return proptools.ConfigurableValueUndefined()
-			}
-			return proptools.ConfigurableValueString(m.base().Arch().ArchType.Name)
+		if !m.base().ArchReady() {
+			ctx.OtherModulePropertyErrorf(m, property, "A select on arch was attempted before the arch mutator ran")
+			return proptools.ConfigurableValueUndefined()
 		}
-		ctx.OtherModulePropertyErrorf(m, property, "Unknown variant %s", condition.Args[0])
-		return proptools.ConfigurableValueUndefined()
+		return proptools.ConfigurableValueString(m.base().Arch().ArchType.Name)
+	case "os":
+		if len(condition.Args) != 0 {
+			ctx.OtherModulePropertyErrorf(m, property, "os requires no arguments, found %d", len(condition.Args))
+			return proptools.ConfigurableValueUndefined()
+		}
+		// the arch mutator runs after the os mutator, we can just use this to enforce that os is ready.
+		if !m.base().ArchReady() {
+			ctx.OtherModulePropertyErrorf(m, property, "A select on os was attempted before the arch mutator ran (arch runs after os, we use it to lazily detect that os is ready)")
+			return proptools.ConfigurableValueUndefined()
+		}
+		return proptools.ConfigurableValueString(m.base().Os().Name)
 	case "boolean_var_for_testing":
 		// We currently don't have any other boolean variables (we should add support for typing
 		// the soong config variables), so add this fake one for testing the boolean select
diff --git a/android/selects_test.go b/android/selects_test.go
index 1eb137beb..f912ce626 100644
--- a/android/selects_test.go
+++ b/android/selects_test.go
@@ -269,11 +269,11 @@ func TestSelects(t *testing.T) {
 			},
 		},
 		{
-			name: "Select on variant",
+			name: "Select on arch",
 			bp: `
 			my_module_type {
 				name: "foo",
-				my_string: select(variant("arch"), {
+				my_string: select(arch(), {
 					"x86": "my_x86",
 					"x86_64": "my_x86_64",
 					"arm": "my_arm",
@@ -286,6 +286,22 @@ func TestSelects(t *testing.T) {
 				my_string: proptools.StringPtr("my_arm64"),
 			},
 		},
+		{
+			name: "Select on os",
+			bp: `
+			my_module_type {
+				name: "foo",
+				my_string: select(os(), {
+					"android": "my_android",
+					"linux": "my_linux",
+					default: "my_default",
+				}),
+			}
+			`,
+			provider: selectsTestProvider{
+				my_string: proptools.StringPtr("my_android"),
+			},
+		},
 		{
 			name: "Unset value",
 			bp: `