Fix a no-op uninstall being treated as a failure

Treat a stageUninstall() doing nothing as a success, not a
failure. This prevents the system retrying the uninstall
later.

Unit tests run with:

make -j30 FrameworksServicesTests
adb install -r -g \
  "out/target/product/marlin/data/app/FrameworksServicesTests/FrameworksServicesTests.apk"
adb shell am instrument -e package com.android.server.timezone -w \
  com.android.frameworks.servicestests \
  "com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner"

Test: See above
Test: Manual testing, adb dumpsys timezone
Test: PTS: run pts -m PtsTimeZoneTestCases
Bug: 65657176
Merged-in: Ifd205da90e848552711ac3f4207cd22ad2c2747b
Change-Id: Ifd205da90e848552711ac3f4207cd22ad2c2747b
(cherry picked from commit 8e27c92)

services/core/java/com/android/server/timezone/RulesManagerService.java

@@ -343,24 +343,28 @@ private class UninstallRunnable implements Runnable {
         @Override
         public void run() {
             EventLogTags.writeTimezoneUninstallStarted(toStringOrNull(mCheckToken));
-            boolean success = false;
+            boolean packageTrackerStatus = false;
             try {
-                success = mInstaller.stageUninstall();
-                // Right now we just have success (0) / failure (1). All clients should be checking
-                // against SUCCESS. More granular failures may be added in future.
-                int resultCode = success ? Callback.SUCCESS
-                        : Callback.ERROR_UNKNOWN_FAILURE;
+                int uninstallResult = mInstaller.stageUninstall();
+                packageTrackerStatus = (uninstallResult == TimeZoneDistroInstaller.UNINSTALL_SUCCESS
+                        || uninstallResult == TimeZoneDistroInstaller.UNINSTALL_NOTHING_INSTALLED);
+
+                // Right now we just have Callback.SUCCESS / Callback.ERROR_UNKNOWN_FAILURE for
+                // uninstall. All clients should be checking against SUCCESS. More granular failures
+                // may be added in future.
+                int callbackResultCode =
+                        packageTrackerStatus ? Callback.SUCCESS : Callback.ERROR_UNKNOWN_FAILURE;
                 EventLogTags.writeTimezoneUninstallComplete(
-                        toStringOrNull(mCheckToken), resultCode);
-                sendFinishedStatus(mCallback, resultCode);
+                        toStringOrNull(mCheckToken), callbackResultCode);
+                sendFinishedStatus(mCallback, callbackResultCode);
             } catch (Exception e) {
                 EventLogTags.writeTimezoneUninstallComplete(
                         toStringOrNull(mCheckToken), Callback.ERROR_UNKNOWN_FAILURE);
                 Slog.w(TAG, "Failed to uninstall distro.", e);
                 sendFinishedStatus(mCallback, Callback.ERROR_UNKNOWN_FAILURE);
             } finally {
                 // Notify the package tracker that the operation is now complete.
-                mPackageTracker.recordCheckResult(mCheckToken, success);
+                mPackageTracker.recordCheckResult(mCheckToken, packageTrackerStatus);
 
                 mOperationInProgress.set(false);
             }

services/tests/servicestests/src/com/android/server/timezone/RulesManagerServiceTest.java

@@ -585,7 +585,39 @@ public void requestUninstall_asyncSuccess() throws Exception {
         verifyNoPackageTrackerCallsMade();
 
         // Set up the installer.
-        configureStageUninstallExpectation(true /* success */);
+        configureStageUninstallExpectation(TimeZoneDistroInstaller.UNINSTALL_SUCCESS);
+
+        // Simulate the async execution.
+        mFakeExecutor.simulateAsyncExecutionOfLastCommand();
+
+        // Verify the expected calls were made to other components.
+        verifyStageUninstallCalled();
+        verifyPackageTrackerCalled(token, true /* success */);
+
+        // Check the callback was called.
+        callback.assertResultReceived(Callback.SUCCESS);
+    }
+
+    @Test
+    public void requestUninstall_asyncNothingInstalled() throws Exception {
+        configureCallerHasPermission();
+
+        CheckToken token = createArbitraryToken();
+        byte[] tokenBytes = token.toByteArray();
+
+        TestCallback callback = new TestCallback();
+
+        // Request the uninstall.
+        assertEquals(RulesManager.SUCCESS,
+                mRulesManagerService.requestUninstall(tokenBytes, callback));
+
+        // Assert nothing has happened yet.
+        callback.assertNoResultReceived();
+        verifyNoInstallerCallsMade();
+        verifyNoPackageTrackerCallsMade();
+
+        // Set up the installer.
+        configureStageUninstallExpectation(TimeZoneDistroInstaller.UNINSTALL_NOTHING_INSTALLED);
 
         // Simulate the async execution.
         mFakeExecutor.simulateAsyncExecutionOfLastCommand();
@@ -613,7 +645,7 @@ public void requestUninstall_nullTokenBytes() throws Exception {
         callback.assertNoResultReceived();
 
         // Set up the installer.
-        configureStageUninstallExpectation(true /* success */);
+        configureStageUninstallExpectation(TimeZoneDistroInstaller.UNINSTALL_SUCCESS);
 
         // Simulate the async execution.
         mFakeExecutor.simulateAsyncExecutionOfLastCommand();
@@ -644,7 +676,7 @@ public void requestUninstall_asyncUninstallFail() throws Exception {
         callback.assertNoResultReceived();
 
         // Set up the installer.
-        configureStageUninstallExpectation(false /* success */);
+        configureStageUninstallExpectation(TimeZoneDistroInstaller.UNINSTALL_FAIL);
 
         // Simulate the async execution.
         mFakeExecutor.simulateAsyncExecutionOfLastCommand();
@@ -849,8 +881,8 @@ private void configureStageInstallExpectation(int resultCode)
                 .thenReturn(resultCode);
     }
 
-    private void configureStageUninstallExpectation(boolean success) throws Exception {
-        doReturn(success).when(mMockTimeZoneDistroInstaller).stageUninstall();
+    private void configureStageUninstallExpectation(int resultCode) throws Exception {
+        doReturn(resultCode).when(mMockTimeZoneDistroInstaller).stageUninstall();
     }
 
     private void verifyStageInstallCalled() throws Exception {