fix(SchemaChecker): don't block on unexpected-table finding

core/Command/Db/CheckSchema.php

@@ -66,6 +66,7 @@ private function printDisabledAppFindings(array $byDisabledApp, OutputInterface
 
 		$output->writeln('Disabled apps (not affecting exit code):');
 		$output->writeln('If the schema for a disabled app differs from what is expected, this might indicate the app was updated since it was disabled. Missing migrations will be applied once the app is enabled again.');
+		$output->writeln("Tables listed under '(unknown app)' could not be attributed to any app - most likely leftovers from an app that was removed entirely (occ app:remove only deletes its code, not its tables or config).");
 		foreach ($byDisabledApp as $app => $appFindings) {
 			$output->writeln("  {$app}:");
 			foreach ($appFindings as $finding) {

core/Command/Upgrade.php

@@ -197,7 +197,7 @@ function ($success) use ($output, $self): void {
 
 			$success = $updater->upgrade();
 
-			$this->postUpgradeCheck($input, $output);
+			$this->postUpgradeCheck($input, $output, $success);
 
 			if (!$success) {
 				return self::ERROR_FAILURE;
@@ -227,8 +227,9 @@ function ($success) use ($output, $self): void {
 	 *
 	 * @param InputInterface $input input interface
 	 * @param OutputInterface $output output interface
+	 * @param bool $upgradeSucceeded whether the upgrade itself completed successfully
 	 */
-	protected function postUpgradeCheck(InputInterface $input, OutputInterface $output) {
+	protected function postUpgradeCheck(InputInterface $input, OutputInterface $output, bool $upgradeSucceeded) {
 		$trustedDomains = $this->config->getSystemValue('trusted_domains', []);
 		if (empty($trustedDomains)) {
 			$output->write(
@@ -238,6 +239,10 @@ protected function postUpgradeCheck(InputInterface $input, OutputInterface $outp
 			);
 		}
 
+		if (!$upgradeSucceeded) {
+			return;
+		}
+
 		$this->checkSchema($output);
 	}
 

lib/private/DB/SchemaChecker.php

@@ -48,7 +48,16 @@ public function getFindings(?string $onlyTable = null): array {
 
 		// Enabled apps are already autoloaded at boot, no extra class loading needed.
 		foreach (array_keys($enabledApps) as $app) {
-			$this->applyMigrations($app, $expectedSchema);
+			try {
+				$this->applyMigrations($app, $expectedSchema);
+			} catch (AppPathNotFoundException) {
+				// Enabled in config, but the app's code is gone: occ app:remove
+				// only deletes an app's code, never its enabled flag, tables or
+				// config (see Installer::removeApp()). Nothing to replay here;
+				// any of its tables still in the live DB surface as
+				// unattributed unexpected_table findings instead of crashing
+				// the whole check.
+			}
 		}
 
 		// Disabled apps keep their tables, so replay their migrations too.
@@ -77,8 +86,20 @@ public function getFindings(?string $onlyTable = null): array {
 		return array_map(function (array $finding) use ($disabledAppTableOwners, $enabledApps, $optionalIndexNames): array {
 			$app = $disabledAppTableOwners[$finding['table']] ?? null;
 			$finding['app'] = $app;
-			// Only tables owned by a disabled app are non-blocking.
-			$finding['enabled'] = $app === null || $app === 'core' || isset($enabledApps[$app]);
+			if ($finding['type'] === 'unexpected_table' && $app === null) {
+				// An unexpected table that cannot be attributed to any known
+				// app is inherently informational, not a sign of drift: occ
+				// app:remove leaves tables and appconfig in place and only
+				// deletes the app's code (see Installer::removeApp()), so a
+				// long-uninstalled app's tables can never be attributed by
+				// applyDisabledMigrations() - there is no code left to replay
+				// migrations from. Treat them the same as residue from a
+				// still-present disabled app instead of blocking on them.
+				$finding['enabled'] = false;
+			} else {
+				// Only tables owned by a disabled app are non-blocking.
+				$finding['enabled'] = $app === null || $app === 'core' || isset($enabledApps[$app]);
+			}
 			$finding['optionalIndex'] = ($finding['type'] === 'missing_index' || $finding['type'] === 'unexpected_index')
 				&& isset($optionalIndexNames[$finding['table']][$finding['name']]);
 			return $finding;
@@ -120,7 +141,10 @@ public function partitionFindings(array $findings): array {
 			} elseif ($finding['enabled']) {
 				$blocking[] = $finding;
 			} else {
-				$byDisabledApp[$finding['app']][] = $finding;
+				// $finding['app'] is null for unattributed unexpected tables
+				// (see getFindings()); group those under a placeholder label
+				// rather than coercing null to an empty-string array key.
+				$byDisabledApp[$finding['app'] ?? '(unknown app)'][] = $finding;
 			}
 		}
 		return ['blocking' => $blocking, 'byDisabledApp' => $byDisabledApp, 'optionalIndices' => $optionalIndices];