gh-79009: sqlite3.iterdump now correctly handles tables with autoincrement (#9621)

Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>

4 files changed, 62 insertions, 1 deletions

diff --git a/Lib/sqlite3/dump.py b/Lib/sqlite3/dump.py
index de9c368..07b9da1 100644
--- a/Lib/sqlite3/dump.py
+++ b/Lib/sqlite3/dump.py
@@ -28,9 +28,16 @@ def _iterdump(connection):
             ORDER BY "name"
         """
     schema_res = cu.execute(q)
+    sqlite_sequence = []
     for table_name, type, sql in schema_res.fetchall():
         if table_name == 'sqlite_sequence':
-            yield('DELETE FROM "sqlite_sequence";')
+            rows = cu.execute('SELECT * FROM "sqlite_sequence";').fetchall()
+            sqlite_sequence = ['DELETE FROM "sqlite_sequence"']
+            sqlite_sequence += [
+                f'INSERT INTO "sqlite_sequence" VALUES(\'{row[0]}\',{row[1]})'
+                for row in rows
+            ]
+            continue
         elif table_name == 'sqlite_stat1':
             yield('ANALYZE "sqlite_master";')
         elif table_name.startswith('sqlite_'):
@@ -67,4 +74,9 @@ def _iterdump(connection):
     for name, type, sql in schema_res.fetchall():
         yield('{0};'.format(sql))
 
+    # gh-79009: Yield statements concerning the sqlite_sequence table at the
+    # end of the transaction.
+    for row in sqlite_sequence:
+        yield('{0};'.format(row))
+
     yield('COMMIT;')
diff --git a/Lib/test/test_sqlite3/test_dump.py b/Lib/test/test_sqlite3/test_dump.py
index 1f14c62..d0c24b9 100644
--- a/Lib/test/test_sqlite3/test_dump.py
+++ b/Lib/test/test_sqlite3/test_dump.py
@@ -2,6 +2,8 @@
 
 import unittest
 import sqlite3 as sqlite
+from .test_dbapi import memory_database
+
 
 class DumpTests(unittest.TestCase):
     def setUp(self):
@@ -49,6 +51,51 @@ class DumpTests(unittest.TestCase):
         [self.assertEqual(expected_sqls[i], actual_sqls[i])
             for i in range(len(expected_sqls))]
 
+    def test_dump_autoincrement(self):
+        expected = [
+            'CREATE TABLE "t1" (id integer primary key autoincrement);',
+            'INSERT INTO "t1" VALUES(NULL);',
+            'CREATE TABLE "t2" (id integer primary key autoincrement);',
+        ]
+        self.cu.executescript("".join(expected))
+
+        # the NULL value should now be automatically be set to 1
+        expected[1] = expected[1].replace("NULL", "1")
+        expected.insert(0, "BEGIN TRANSACTION;")
+        expected.extend([
+            'DELETE FROM "sqlite_sequence";',
+            'INSERT INTO "sqlite_sequence" VALUES(\'t1\',1);',
+            'COMMIT;',
+        ])
+
+        actual = [stmt for stmt in self.cx.iterdump()]
+        self.assertEqual(expected, actual)
+
+    def test_dump_autoincrement_create_new_db(self):
+        self.cu.execute("BEGIN TRANSACTION")
+        self.cu.execute("CREATE TABLE t1 (id integer primary key autoincrement)")
+        self.cu.execute("CREATE TABLE t2 (id integer primary key autoincrement)")
+        self.cu.executemany("INSERT INTO t1 VALUES(?)", ((None,) for _ in range(9)))
+        self.cu.executemany("INSERT INTO t2 VALUES(?)", ((None,) for _ in range(4)))
+        self.cx.commit()
+
+        with memory_database() as cx2:
+            query = "".join(self.cx.iterdump())
+            cx2.executescript(query)
+            cu2 = cx2.cursor()
+
+            dataset = (
+                ("t1", 9),
+                ("t2", 4),
+            )
+            for table, seq in dataset:
+                with self.subTest(table=table, seq=seq):
+                    res = cu2.execute("""
+                        SELECT "seq" FROM "sqlite_sequence" WHERE "name" == ?
+                    """, (table,))
+                    rows = res.fetchall()
+                    self.assertEqual(rows[0][0], seq)
+
     def test_unorderable_row(self):
         # iterdump() should be able to cope with unorderable row types (issue #15545)
         class UnorderableRow:
diff --git a/Misc/ACKS b/Misc/ACKS
index c3a4f9b..b634041 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -934,6 +934,7 @@ Ron Klatchko
 Reid Kleckner
 Carsten Klein
 Bastian Kleineidam
+Joel Klimont
 Bob Kline
 Matthias Klose
 Jeremy Kloth
diff --git a/Misc/NEWS.d/next/Library/2018-09-28-22-18-03.bpo-34828.5Zyi_S.rst b/Misc/NEWS.d/next/Library/2018-09-28-22-18-03.bpo-34828.5Zyi_S.rst
new file mode 100644
index 0000000..b0e10a1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-09-28-22-18-03.bpo-34828.5Zyi_S.rst
@@ -0,0 +1 @@
+:meth:`sqlite3.Connection.iterdump` now handles databases that use ``AUTOINCREMENT`` in one or more tables.