[UidMigration] fix update uninstallation with sharedUserMaxSdkVersion

When a system app is re-enabled after the update is uninstalled, when
the system app has shared uid, the current code doesn't support
directly reusing the disabled package setting. Instead, the preloaded
version is re-scanned and installed as a new app, which can bring
breaking behavior of changed UIDs when the manifest has
sharedUserMaxSdkVersion.

This change fixes the bug where registerExistingAppId fails when it
comes to shared uid, therefore directly reuses the disabled package
setting, consistent with the behavior for non-shared-uid system apps.

FLAG: EXEMPT BUGFIX
Test: manually with system-app-test.sh
BUG: 454062218



(cherry picked from commit 6b5ea2f7fbf50313d46e54e0d8f8c18c398e4869)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:740256b41ba113708655f82dc5664291bf79edd0
Merged-In: I417cec27697a210416027e862a5e5d207d268b82
Change-Id: I417cec27697a210416027e862a5e5d207d268b82

services/core/java/com/android/server/pm/Settings.java

diff --git a/services/core/java/com/android/server/pm/Settings.java b/services/core/java/com/android/server/pm/Settings.java
index 92257f1..ab13d7e 100644
--- a/services/core/java/com/android/server/pm/Settings.java
+++ b/services/core/java/com/android/server/pm/Settings.java
@@ -916,8 +916,8 @@
         p.getPkgState().setUpdatedSystemApp(false);
         final AndroidPackageInternal pkg = p.getPkg();
         PackageSetting ret = addPackageLPw(name, p.getRealName(), p.getPath(), p.getAppId(),
-                p.getFlags(), p.getPrivateFlags(), mDomainVerificationManager.generateNewId(),
-                pkg == null ? false : pkg.isSdkLibrary());
+                    p.getFlags(), p.getPrivateFlags(), mDomainVerificationManager.generateNewId(),
+                    pkg == null ? false : pkg.isSdkLibrary(), p.hasSharedUser());
         if (ret != null) {
             ret.setLegacyNativeLibraryPath(p.getLegacyNativeLibraryPath());
             ret.setPrimaryCpuAbi(p.getPrimaryCpuAbiLegacy());
@@ -937,6 +937,7 @@
             ret.setRestrictUpdateHash(p.getRestrictUpdateHash());
             ret.setScannedAsStoppedSystemApp(p.isScannedAsStoppedSystemApp());
             ret.setInstallSource(p.getInstallSource());
+            ret.setSharedUserAppId(p.getSharedUserAppId());
         }
         mDisabledSysPackages.remove(name);
         return ret;
@@ -958,7 +959,8 @@
     }
 
     PackageSetting addPackageLPw(String name, String realName, File codePath, int uid,
-            int pkgFlags, int pkgPrivateFlags, @NonNull UUID domainSetId, boolean isSdkLibrary) {
+            int pkgFlags, int pkgPrivateFlags, @NonNull UUID domainSetId, boolean isSdkLibrary,
+            boolean hasSharedUser) {
         PackageSetting p = mPackages.get(name);
         if (p != null) {
             if (p.getAppId() == uid) {
@@ -971,7 +973,8 @@
         p = new PackageSetting(name, realName, codePath, pkgFlags, pkgPrivateFlags, domainSetId)
                 .setAppId(uid);
         if ((uid == Process.INVALID_UID && isSdkLibrary && Flags.disallowSdkLibsToBeApps())
-                || mAppIds.registerExistingAppId(uid, p, name)) {
+                || mAppIds.registerExistingAppId(uid, p, name)
+                || hasSharedUser) {
             mPackages.put(name, p);
             return p;
         }
@@ -4266,7 +4269,8 @@
             } else if (appId > 0 || (appId == Process.INVALID_UID && isSdkLibrary
                     && Flags.disallowSdkLibsToBeApps())) {
                 packageSetting = addPackageLPw(name.intern(), realName, new File(codePathStr),
-                        appId, pkgFlags, pkgPrivateFlags, domainSetId, isSdkLibrary);
+                        appId, pkgFlags, pkgPrivateFlags, domainSetId, isSdkLibrary,
+                        /* hasSharedUser= */ false);
                 if (PackageManagerService.DEBUG_SETTINGS)
                     Log.i(PackageManagerService.TAG, "Reading package " + name + ": appId="
                             + appId + " pkg=" + packageSetting);

services/tests/mockingservicestests/src/com/android/server/pm/MockSystem.kt

diff --git a/services/tests/mockingservicestests/src/com/android/server/pm/MockSystem.kt b/services/tests/mockingservicestests/src/com/android/server/pm/MockSystem.kt
index 1b2ab27..9a73ba3 100644
--- a/services/tests/mockingservicestests/src/com/android/server/pm/MockSystem.kt
+++ b/services/tests/mockingservicestests/src/com/android/server/pm/MockSystem.kt
@@ -168,7 +168,7 @@
             null
         }
         whenever(mocks.settings.addPackageLPw(nullable(), nullable(), nullable(), nullable(),
-                nullable(), nullable(), nullable(), nullable())) {
+                nullable(), nullable(), nullable(), nullable(), nullable())) {
             val name: String = getArgument(0)
             val pendingAdd = mPendingPackageAdds.firstOrNull { it.first == name }
                     ?: return@whenever null