Ignore internal tables when reading schema from db

drift_dev/lib/src/services/schema/sqlite_to_drift.dart

@@ -1,5 +1,6 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:drift_dev/src/analysis/options.dart';
+import 'package:drift_dev/src/services/schema/verifier_impl.dart';
 import 'package:logging/logging.dart';
 import 'package:sqlite3/common.dart';
 import 'package:sqlparser/sqlparser.dart';
@@ -17,16 +18,9 @@ import '../../analysis/results/results.dart';
 Future<List<DriftElement>> extractDriftElementsFromDatabase(
     CommonDatabase database) async {
   // Put everything from sqlite_schema into a fake drift file, analyze it.
-  final contents = database
-      .select('select * from sqlite_master')
-      .map((row) => row['sql'])
-      .whereType<String>()
-      .map((sql) => sql.endsWith(';') ? sql : '$sql;')
-      .join('\n');
-
   final logger = Logger('extractDriftElementsFromDatabase');
   final uri = Uri.parse('db.drift');
-  final backend = _SingleFileNoAnalyzerBackend(logger, contents, uri);
+  final backend = _SingleFileNoAnalyzerBackend(logger, uri);
   final driver = DriftAnalysisDriver(
     backend,
     DriftOptions.defaults(
@@ -37,8 +31,38 @@ Future<List<DriftElement>> extractDriftElementsFromDatabase(
     ),
   );
 
-  final file = await driver.fullyAnalyze(uri);
+  final engineForParsing = driver.newSqlEngine();
+  final entities = <String, String>{};
+  final virtualTableNames = <String>[];
+  for (final row in database.select('select * from sqlite_master')) {
+    final name = row['name'] as String?;
+    var sql = row['sql'] as String?;
 
+    if (name == null ||
+        sql == null ||
+        isInternalElement(name, virtualTableNames)) {
+      continue;
+    }
+
+    if (!sql.endsWith(';')) {
+      sql += ';';
+    }
+
+    final parsed = engineForParsing.parse(sql).rootNode;
+
+    // Virtual table modules often add auxiliary tables that aren't part of the
+    // user-defined database schema. So we need to keep track of them to be
+    // able to filter internal tables out.
+    if (parsed is CreateVirtualTableStatement) {
+      virtualTableNames.add(parsed.tableName);
+    }
+
+    entities[name] = sql;
+  }
+  entities.removeWhere((name, _) => isInternalElement(name, virtualTableNames));
+  backend.contents = entities.values.join('\n');
+
+  final file = await driver.fullyAnalyze(uri);
   return [
     for (final entry in file.analysis.values)
       if (entry.result != null) entry.result!
@@ -49,10 +73,10 @@ class _SingleFileNoAnalyzerBackend extends DriftBackend {
   @override
   final Logger log;
 
-  final String file;
+  late final String contents;
   final Uri uri;
 
-  _SingleFileNoAnalyzerBackend(this.log, this.file, this.uri);
+  _SingleFileNoAnalyzerBackend(this.log, this.uri);
 
   Never _noAnalyzer() =>
       throw UnsupportedError('Dart analyzer not available here');
@@ -64,7 +88,7 @@ class _SingleFileNoAnalyzerBackend extends DriftBackend {
 
   @override
   Future<String> readAsString(Uri uri) {
-    return Future.value(file);
+    return Future.value(contents);
   }
 
   @override

drift_dev/lib/src/services/schema/verifier_impl.dart

@@ -81,16 +81,26 @@ class VerifierImplementation implements SchemaVerifier {
 Input? _parseInputFromSchemaRow(
     Map<String, Object?> row, List<String> virtualTables) {
   final name = row['name'] as String;
+  if (isInternalElement(name, virtualTables)) {
+    return null;
+  }
 
+  return Input(name, row['sql'] as String);
+}
+
+/// Attempts to recognize whether [name] is likely the name of an internal
+/// sqlite3 table (like `sqlite3_sequence`) that we should not consider when
+/// comparing schemas.
+bool isInternalElement(String name, List<String> virtualTables) {
   // Skip sqlite-internal tables, https://www.sqlite.org/fileformat2.html#intschema
-  if (name.startsWith('sqlite_')) return null;
-  if (virtualTables.any((v) => name.startsWith('${v}_'))) return null;
+  if (name.startsWith('sqlite_')) return true;
+  if (virtualTables.any((v) => name.startsWith('${v}_'))) return true;
 
   // This file is added on some Android versions when using the native Android
   // database APIs, https://github.com/simolus3/drift/discussions/2042
-  if (name == 'android_metadata') return null;
+  if (name == 'android_metadata') return true;
 
-  return Input(name, row['sql'] as String);
+  return false;
 }
 
 extension CollectSchemaDb on DatabaseConnectionUser {

drift_dev/test/services/schema/sqlite_to_drift_test.dart

@@ -0,0 +1,46 @@
+import 'package:drift_dev/src/analysis/results/results.dart';
+import 'package:drift_dev/src/services/schema/sqlite_to_drift.dart';
+import 'package:sqlite3/sqlite3.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('can extract elements from database', () async {
+    final database = sqlite3.openInMemory()
+      ..execute('CREATE TABLE foo (id INTEGER PRIMARY KEY, bar TEXT);')
+      ..execute('CREATE INDEX my_idx ON foo (bar)')
+      ..execute('CREATE VIEW my_view AS SELECT bar FROM foo')
+      ..execute('CREATE TRIGGER my_trigger AFTER UPDATE ON foo BEGIN '
+          'UPDATE foo SET bar = old.bar; '
+          'END;');
+    addTearDown(database.dispose);
+
+    final elements = await extractDriftElementsFromDatabase(database);
+    expect(
+      elements,
+      unorderedEquals([
+        isA<DriftTable>().having((e) => e.schemaName, 'schemaName', 'foo'),
+        isA<DriftIndex>().having((e) => e.schemaName, 'schemaName', 'my_idx'),
+        isA<DriftView>().having((e) => e.schemaName, 'schemaName', 'my_view'),
+        isA<DriftTrigger>()
+            .having((e) => e.schemaName, 'schemaName', 'my_trigger'),
+      ]),
+    );
+  });
+
+  test('ignores internal tables', () async {
+    final database = sqlite3.openInMemory()
+      ..execute('CREATE TABLE my_table (id INTEGER PRIMARY KEY AUTOINCREMENT)')
+      ..execute('CREATE VIRTUAL TABLE foo USING fts5(x,y, z);');
+
+    addTearDown(database.dispose);
+
+    final elements = await extractDriftElementsFromDatabase(database);
+    expect(
+      elements,
+      unorderedEquals([
+        isA<DriftTable>().having((e) => e.schemaName, 'schemaName', 'my_table'),
+        isA<DriftTable>().having((e) => e.schemaName, 'schemaName', 'foo'),
+      ]),
+    );
+  });
+}

examples/flutter_web_worker_example/lib/src/database/database.g.dart

@@ -168,8 +168,6 @@ class Entries extends Table with TableInfo<Entries, Entrie> {
     return Entries(attachedDatabase, alias);
   }
 
-  @override
-  List<String> get customConstraints => const [];
   @override
   bool get dontWriteConstraints => true;
 }

examples/web_worker_example/lib/database.g.dart

@@ -168,8 +168,6 @@ class Entries extends Table with TableInfo<Entries, Entrie> {
     return Entries(attachedDatabase, alias);
   }
 
-  @override
-  List<String> get customConstraints => const [];
   @override
   bool get dontWriteConstraints => true;
 }