Introduce BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES

If BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES has a numeric value,
it replaces "current" or "system_current" with the version which
the flag indicates.

Bug: 163009188
Test: BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES=29 m, and then check if every vendor
java module's sdk_version is 29 if its sdk_version was current.

Change-Id: I17b49b8e02caf2d1bc57b91648d4420f3ad9fcb9
diff --git a/android/config.go b/android/config.go
index 13e55bc..dd622e5 100644
--- a/android/config.go
+++ b/android/config.go
@@ -35,6 +35,7 @@
 
 var Bool = proptools.Bool
 var String = proptools.String
+var StringDefault = proptools.StringDefault
 
 const FutureApiLevel = 10000
 
@@ -958,6 +959,10 @@
 	return String(c.config.productVariables.DeviceVndkVersion)
 }
 
+func (c *deviceConfig) CurrentApiLevelForVendorModules() string {
+	return StringDefault(c.config.productVariables.DeviceCurrentApiLevelForVendorModules, "current")
+}
+
 func (c *deviceConfig) PlatformVndkVersion() string {
 	return String(c.config.productVariables.Platform_vndk_version)
 }
diff --git a/android/variable.go b/android/variable.go
index 1f21f34..53f081e 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -166,13 +166,14 @@
 	Platform_min_supported_target_sdk_version *string  `json:",omitempty"`
 	Platform_base_os                          *string  `json:",omitempty"`
 
-	DeviceName              *string  `json:",omitempty"`
-	DeviceArch              *string  `json:",omitempty"`
-	DeviceArchVariant       *string  `json:",omitempty"`
-	DeviceCpuVariant        *string  `json:",omitempty"`
-	DeviceAbi               []string `json:",omitempty"`
-	DeviceVndkVersion       *string  `json:",omitempty"`
-	DeviceSystemSdkVersions []string `json:",omitempty"`
+	DeviceName                            *string  `json:",omitempty"`
+	DeviceArch                            *string  `json:",omitempty"`
+	DeviceArchVariant                     *string  `json:",omitempty"`
+	DeviceCpuVariant                      *string  `json:",omitempty"`
+	DeviceAbi                             []string `json:",omitempty"`
+	DeviceVndkVersion                     *string  `json:",omitempty"`
+	DeviceCurrentApiLevelForVendorModules *string  `json:",omitempty"`
+	DeviceSystemSdkVersions               []string `json:",omitempty"`
 
 	DeviceSecondaryArch        *string  `json:",omitempty"`
 	DeviceSecondaryArchVariant *string  `json:",omitempty"`
diff --git a/java/app_test.go b/java/app_test.go
index 6b27124..53d1f0b 100644
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -1038,6 +1038,35 @@
 	}
 }
 
+func checkSdkVersion(t *testing.T, config android.Config, expectedSdkVersion string) {
+	ctx := testContext()
+
+	run(t, ctx, config)
+
+	foo := ctx.ModuleForTests("foo", "android_common")
+	link := foo.Output("package-res.apk")
+	linkFlags := strings.Split(link.Args["flags"], " ")
+	min := android.IndexList("--min-sdk-version", linkFlags)
+	target := android.IndexList("--target-sdk-version", linkFlags)
+
+	if min == -1 || target == -1 || min == len(linkFlags)-1 || target == len(linkFlags)-1 {
+		t.Fatalf("missing --min-sdk-version or --target-sdk-version in link flags: %q", linkFlags)
+	}
+
+	gotMinSdkVersion := linkFlags[min+1]
+	gotTargetSdkVersion := linkFlags[target+1]
+
+	if gotMinSdkVersion != expectedSdkVersion {
+		t.Errorf("incorrect --min-sdk-version, expected %q got %q",
+			expectedSdkVersion, gotMinSdkVersion)
+	}
+
+	if gotTargetSdkVersion != expectedSdkVersion {
+		t.Errorf("incorrect --target-sdk-version, expected %q got %q",
+			expectedSdkVersion, gotTargetSdkVersion)
+	}
+}
+
 func TestAppSdkVersion(t *testing.T) {
 	testCases := []struct {
 		name                  string
@@ -1107,38 +1136,85 @@
 				config.TestProductVariables.Platform_sdk_version = &test.platformSdkInt
 				config.TestProductVariables.Platform_sdk_codename = &test.platformSdkCodename
 				config.TestProductVariables.Platform_sdk_final = &test.platformSdkFinal
+				checkSdkVersion(t, config, test.expectedMinSdkVersion)
 
-				ctx := testContext()
-
-				run(t, ctx, config)
-
-				foo := ctx.ModuleForTests("foo", "android_common")
-				link := foo.Output("package-res.apk")
-				linkFlags := strings.Split(link.Args["flags"], " ")
-				min := android.IndexList("--min-sdk-version", linkFlags)
-				target := android.IndexList("--target-sdk-version", linkFlags)
-
-				if min == -1 || target == -1 || min == len(linkFlags)-1 || target == len(linkFlags)-1 {
-					t.Fatalf("missing --min-sdk-version or --target-sdk-version in link flags: %q", linkFlags)
-				}
-
-				gotMinSdkVersion := linkFlags[min+1]
-				gotTargetSdkVersion := linkFlags[target+1]
-
-				if gotMinSdkVersion != test.expectedMinSdkVersion {
-					t.Errorf("incorrect --min-sdk-version, expected %q got %q",
-						test.expectedMinSdkVersion, gotMinSdkVersion)
-				}
-
-				if gotTargetSdkVersion != test.expectedMinSdkVersion {
-					t.Errorf("incorrect --target-sdk-version, expected %q got %q",
-						test.expectedMinSdkVersion, gotTargetSdkVersion)
-				}
 			})
 		}
 	}
 }
 
+func TestVendorAppSdkVersion(t *testing.T) {
+	testCases := []struct {
+		name                                  string
+		sdkVersion                            string
+		platformSdkInt                        int
+		platformSdkCodename                   string
+		platformSdkFinal                      bool
+		deviceCurrentApiLevelForVendorModules string
+		expectedMinSdkVersion                 string
+	}{
+		{
+			name:                                  "current final SDK",
+			sdkVersion:                            "current",
+			platformSdkInt:                        29,
+			platformSdkCodename:                   "REL",
+			platformSdkFinal:                      true,
+			deviceCurrentApiLevelForVendorModules: "29",
+			expectedMinSdkVersion:                 "29",
+		},
+		{
+			name:                                  "current final SDK",
+			sdkVersion:                            "current",
+			platformSdkInt:                        29,
+			platformSdkCodename:                   "REL",
+			platformSdkFinal:                      true,
+			deviceCurrentApiLevelForVendorModules: "28",
+			expectedMinSdkVersion:                 "28",
+		},
+		{
+			name:                                  "current final SDK",
+			sdkVersion:                            "current",
+			platformSdkInt:                        29,
+			platformSdkCodename:                   "Q",
+			platformSdkFinal:                      false,
+			deviceCurrentApiLevelForVendorModules: "current",
+			expectedMinSdkVersion:                 "Q",
+		},
+		{
+			name:                                  "current final SDK",
+			sdkVersion:                            "current",
+			platformSdkInt:                        29,
+			platformSdkCodename:                   "Q",
+			platformSdkFinal:                      false,
+			deviceCurrentApiLevelForVendorModules: "28",
+			expectedMinSdkVersion:                 "28",
+		},
+	}
+
+	for _, moduleType := range []string{"android_app", "android_library"} {
+		for _, sdkKind := range []string{"", "system_"} {
+			for _, test := range testCases {
+				t.Run(moduleType+" "+test.name, func(t *testing.T) {
+					bp := fmt.Sprintf(`%s {
+						name: "foo",
+						srcs: ["a.java"],
+						sdk_version: "%s%s",
+						vendor: true,
+					}`, moduleType, sdkKind, test.sdkVersion)
+
+					config := testAppConfig(nil, bp, nil)
+					config.TestProductVariables.Platform_sdk_version = &test.platformSdkInt
+					config.TestProductVariables.Platform_sdk_codename = &test.platformSdkCodename
+					config.TestProductVariables.Platform_sdk_final = &test.platformSdkFinal
+					config.TestProductVariables.DeviceCurrentApiLevelForVendorModules = &test.deviceCurrentApiLevelForVendorModules
+					config.TestProductVariables.DeviceSystemSdkVersions = []string{"28", "29"}
+					checkSdkVersion(t, config, test.expectedMinSdkVersion)
+				})
+			}
+		}
+	}
+}
+
 func TestJNIABI(t *testing.T) {
 	ctx, _ := testJava(t, cc.GatherRequiredDepsForTest(android.Android)+`
 		cc_library {
diff --git a/java/sdk.go b/java/sdk.go
index b44cd8e1..56fa12b 100644
--- a/java/sdk.go
+++ b/java/sdk.go
@@ -191,6 +191,26 @@
 	return s.kind != sdkPrivate && s.kind != sdkNone && s.kind != sdkCorePlatform
 }
 
+func (s sdkSpec) forVendorPartition(ctx android.EarlyModuleContext) sdkSpec {
+	// If BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES has a numeric value,
+	// use it instead of "current" for the vendor partition.
+	currentSdkVersion := ctx.DeviceConfig().CurrentApiLevelForVendorModules()
+	if currentSdkVersion == "current" {
+		return s
+	}
+
+	if s.kind == sdkPublic || s.kind == sdkSystem {
+		if s.version.isCurrent() {
+			if i, err := strconv.Atoi(currentSdkVersion); err == nil {
+				version := sdkVersion(i)
+				return sdkSpec{s.kind, version, s.raw}
+			}
+			panic(fmt.Errorf("BOARD_CURRENT_API_LEVEL_FOR_VENDOR_MODULES must be either \"current\" or a number, but was %q", currentSdkVersion))
+		}
+	}
+	return s
+}
+
 // usePrebuilt determines whether prebuilt SDK should be used for this sdkSpec with the given context.
 func (s sdkSpec) usePrebuilt(ctx android.EarlyModuleContext) bool {
 	if s.version.isCurrent() {
@@ -216,6 +236,10 @@
 	if !s.valid() {
 		return s.version, fmt.Errorf("invalid sdk version %q", s.raw)
 	}
+
+	if ctx.DeviceSpecific() || ctx.SocSpecific() {
+		s = s.forVendorPartition(ctx)
+	}
 	if s.version.isNumbered() {
 		return s.version, nil
 	}
@@ -330,6 +354,10 @@
 		return sdkDep{}
 	}
 
+	if ctx.DeviceSpecific() || ctx.SocSpecific() {
+		sdkVersion = sdkVersion.forVendorPartition(ctx)
+	}
+
 	if !sdkVersion.validateSystemSdk(ctx) {
 		return sdkDep{}
 	}
diff --git a/java/testing.go b/java/testing.go
index 1e725fa..1db6ef2 100644
--- a/java/testing.go
+++ b/java/testing.go
@@ -44,6 +44,9 @@
 		"prebuilts/sdk/17/public/android.jar":                      nil,
 		"prebuilts/sdk/17/public/framework.aidl":                   nil,
 		"prebuilts/sdk/17/system/android.jar":                      nil,
+		"prebuilts/sdk/28/public/android.jar":                      nil,
+		"prebuilts/sdk/28/public/framework.aidl":                   nil,
+		"prebuilts/sdk/28/system/android.jar":                      nil,
 		"prebuilts/sdk/29/public/android.jar":                      nil,
 		"prebuilts/sdk/29/public/framework.aidl":                   nil,
 		"prebuilts/sdk/29/system/android.jar":                      nil,