Export release flag types to make/soong

And use the types to appropriately type selects on the release
variables.

Bug: 323382414
Test: Presubmits
Change-Id: Ide7eca95662caaa7b4be42e20399d9fcd7fed35f

android/module.go

@@ -2157,8 +2157,18 @@ func (e configurationEvalutor) EvaluateConfiguration(condition proptools.Configu
 			ctx.OtherModulePropertyErrorf(m, property, "release_flag requires 1 argument, found %d", condition.NumArgs())
 			return proptools.ConfigurableValueUndefined()
 		}
-		if v, ok := ctx.Config().productVariables.BuildFlags[condition.Arg(0)]; ok {
+		if ty, ok := ctx.Config().productVariables.BuildFlagTypes[condition.Arg(0)]; ok {
-			return proptools.ConfigurableValueString(v)
+			v := ctx.Config().productVariables.BuildFlags[condition.Arg(0)]
+			switch ty {
+			case "unspecified", "obsolete":
+				return proptools.ConfigurableValueUndefined()
+			case "string":
+				return proptools.ConfigurableValueString(v)
+			case "bool":
+				return proptools.ConfigurableValueBool(v == "true")
+			default:
+				panic("unhandled release flag type: " + ty)
+			}
 		}
 		return proptools.ConfigurableValueUndefined()
 	case "product_variable":

android/variable.go

@@ -492,6 +492,8 @@ type ProductVariables struct {
 
 	BuildFlags map[string]string `json:",omitempty"`
 
+	BuildFlagTypes map[string]string `json:",omitempty"`
+
 	BuildFromSourceStub *bool `json:",omitempty"`
 
 	BuildIgnoreApexContributionContents *bool `json:",omitempty"`

cmd/release_config/release_config_lib/flag_value.go

@@ -74,3 +74,22 @@ func MarshalValue(value *rc_proto.Value) string {
 		return ""
 	}
 }
+
+// Returns a string representation of the type of the value for make
+func ValueType(value *rc_proto.Value) string {
+	if value == nil || value.Val == nil {
+		return "unspecified"
+	}
+	switch value.Val.(type) {
+	case *rc_proto.Value_UnspecifiedValue:
+		return "unspecified"
+	case *rc_proto.Value_StringValue:
+		return "string"
+	case *rc_proto.Value_BoolValue:
+		return "bool"
+	case *rc_proto.Value_Obsolete:
+		return "obsolete"
+	default:
+		panic("Unhandled type")
+	}
+}

cmd/release_config/release_config_lib/release_configs.go

@@ -348,6 +348,7 @@ func (configs *ReleaseConfigs) WriteMakefile(outFile, targetRelease string) erro
 		}
 		value := MarshalValue(flag.Value)
 		makeVars[name] = value
+		addVar(name, "TYPE", ValueType(flag.Value))
 		addVar(name, "PARTITIONS", strings.Join(decl.Containers, " "))
 		addVar(name, "DEFAULT", MarshalValue(decl.Value))
 		addVar(name, "VALUE", value)
@@ -356,7 +357,7 @@ func (configs *ReleaseConfigs) WriteMakefile(outFile, targetRelease string) erro
 		addVar(name, "NAMESPACE", *decl.Namespace)
 	}
 	pNames := []string{}
-	for k, _ := range partitions {
+	for k := range partitions {
 		pNames = append(pNames, k)
 	}
 	slices.SortFunc(pNames, func(a, b string) int {