Ensure APEX's Java deps use stable SDKs.

Test: m
Bug: 153333044
Change-Id: Ib1acf3073e96fe23c92d292ec0b1a91e2cd408db
Merged-In: Ib1acf3073e96fe23c92d292ec0b1a91e2cd408db
Exempt-From-Owner-Approval: cp from aosp
(cherry picked from commit 8cf899afcc69643f63350bc9f9f92677bb8feabd)
diff --git a/apex/apex.go b/apex/apex.go
index 6a0c4c1..7191365 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -1871,6 +1871,8 @@
 		if String(a.properties.Min_sdk_version) == "" {
 			ctx.PropertyErrorf("updatable", "updatable APEXes should set min_sdk_version as well")
 		}
+
+		a.checkJavaStableSdkVersion(ctx)
 	}
 }
 
@@ -1940,7 +1942,6 @@
 
 	a.checkApexAvailability(ctx)
 	a.checkUpdatable(ctx)
-
 	a.collectDepsInfo(ctx)
 
 	handleSpecialLibs := !android.Bool(a.properties.Ignore_system_library_special_case)
@@ -2247,6 +2248,23 @@
 	a.buildApexDependencyInfo(ctx)
 }
 
+// Enforce that Java deps of the apex are using stable SDKs to compile
+func (a *apexBundle) checkJavaStableSdkVersion(ctx android.ModuleContext) {
+	// Visit direct deps only. As long as we guarantee top-level deps are using
+	// stable SDKs, java's checkLinkType guarantees correct usage for transitive deps
+	ctx.VisitDirectDepsBlueprint(func(module blueprint.Module) {
+		tag := ctx.OtherModuleDependencyTag(module)
+		switch tag {
+		case javaLibTag, androidAppTag:
+			if m, ok := module.(interface{ CheckStableSdkVersion() error }); ok {
+				if err := m.CheckStableSdkVersion(); err != nil {
+					ctx.ModuleErrorf("cannot depend on \"%v\": %v", ctx.OtherModuleName(module), err)
+				}
+			}
+		}
+	})
+}
+
 func whitelistedApexAvailable(apex, moduleName string) bool {
 	key := apex
 	moduleName = normalizeModuleName(moduleName)
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 2618db3..f1d80ae 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -1377,6 +1377,122 @@
 	`)
 }
 
+func TestJavaStableSdkVersion(t *testing.T) {
+	testCases := []struct {
+		name          string
+		expectedError string
+		bp            string
+	}{
+		{
+			name: "Non-updatable apex with non-stable dep",
+			bp: `
+				apex {
+					name: "myapex",
+					java_libs: ["myjar"],
+					key: "myapex.key",
+				}
+				apex_key {
+					name: "myapex.key",
+					public_key: "testkey.avbpubkey",
+					private_key: "testkey.pem",
+				}
+				java_library {
+					name: "myjar",
+					srcs: ["foo/bar/MyClass.java"],
+					sdk_version: "core_platform",
+					apex_available: ["myapex"],
+				}
+			`,
+		},
+		{
+			name: "Updatable apex with stable dep",
+			bp: `
+				apex {
+					name: "myapex",
+					java_libs: ["myjar"],
+					key: "myapex.key",
+					updatable: true,
+					min_sdk_version: "29",
+				}
+				apex_key {
+					name: "myapex.key",
+					public_key: "testkey.avbpubkey",
+					private_key: "testkey.pem",
+				}
+				java_library {
+					name: "myjar",
+					srcs: ["foo/bar/MyClass.java"],
+					sdk_version: "current",
+					apex_available: ["myapex"],
+				}
+			`,
+		},
+		{
+			name:          "Updatable apex with non-stable dep",
+			expectedError: "cannot depend on \"myjar\"",
+			bp: `
+				apex {
+					name: "myapex",
+					java_libs: ["myjar"],
+					key: "myapex.key",
+					updatable: true,
+				}
+				apex_key {
+					name: "myapex.key",
+					public_key: "testkey.avbpubkey",
+					private_key: "testkey.pem",
+				}
+				java_library {
+					name: "myjar",
+					srcs: ["foo/bar/MyClass.java"],
+					sdk_version: "core_platform",
+					apex_available: ["myapex"],
+				}
+			`,
+		},
+		{
+			name:          "Updatable apex with non-stable transitive dep",
+			expectedError: "compiles against Android API, but dependency \"transitive-jar\" is compiling against non-public Android API.",
+			bp: `
+				apex {
+					name: "myapex",
+					java_libs: ["myjar"],
+					key: "myapex.key",
+					updatable: true,
+				}
+				apex_key {
+					name: "myapex.key",
+					public_key: "testkey.avbpubkey",
+					private_key: "testkey.pem",
+				}
+				java_library {
+					name: "myjar",
+					srcs: ["foo/bar/MyClass.java"],
+					sdk_version: "current",
+					apex_available: ["myapex"],
+					static_libs: ["transitive-jar"],
+				}
+				java_library {
+					name: "transitive-jar",
+					srcs: ["foo/bar/MyClass.java"],
+					sdk_version: "core_platform",
+					apex_available: ["myapex"],
+				}
+			`,
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			if test.expectedError == "" {
+				testApex(t, test.bp)
+			} else {
+				testApexError(t, test.expectedError, test.bp)
+			}
+		})
+	}
+}
+
 func TestFilesInSubDir(t *testing.T) {
 	ctx, _ := testApex(t, `
 		apex {
@@ -4289,6 +4405,7 @@
 		java_library {
 			name: "some-updatable-apex-lib",
 			srcs: ["a.java"],
+			sdk_version: "current",
 			apex_available: [
 				"some-updatable-apex",
 			],
@@ -4297,12 +4414,14 @@
 		java_library {
 			name: "some-platform-lib",
 			srcs: ["a.java"],
+			sdk_version: "current",
 			installable: true,
 		}
 
 		java_library {
 			name: "some-art-lib",
 			srcs: ["a.java"],
+			sdk_version: "current",
 			apex_available: [
 				"com.android.art.something",
 			],
diff --git a/java/java.go b/java/java.go
index 5d77807..6589721 100644
--- a/java/java.go
+++ b/java/java.go
@@ -86,6 +86,14 @@
 	ctx.RegisterSingletonType("kythe_java_extract", kytheExtractJavaFactory)
 }
 
+func (j *Module) CheckStableSdkVersion() error {
+	sdkVersion := j.sdkVersion()
+	if sdkVersion.stable() {
+		return nil
+	}
+	return fmt.Errorf("non stable SDK %v", sdkVersion)
+}
+
 func (j *Module) checkSdkVersions(ctx android.ModuleContext) {
 	if j.SocSpecific() || j.DeviceSpecific() ||
 		(j.ProductSpecific() && ctx.Config().EnforceProductPartitionInterface()) {
diff --git a/java/sdk.go b/java/sdk.go
index be5e512..4414600 100644
--- a/java/sdk.go
+++ b/java/sdk.go
@@ -170,9 +170,12 @@
 		return false
 	}
 	switch s.kind {
+	case sdkNone:
+		// there is nothing to manage and version in this case; de facto stable API.
+		return true
 	case sdkCore, sdkPublic, sdkSystem, sdkModule, sdkSystemServer:
 		return true
-	case sdkNone, sdkCorePlatform, sdkTest, sdkPrivate:
+	case sdkCorePlatform, sdkTest, sdkPrivate:
 		return false
 	default:
 		panic(fmt.Errorf("unknown sdkKind=%v", s.kind))