[1.9.x] Fixed #26627 -- Fixed on_commit callbacks execution order when callbacks make transactions.

Backport of a5c8072ab1e56da368a40f3e9c9a3b465f4ffbae from master

3 files changed, 22 insertions, 6 deletions

diff --git a/django/db/backends/base/base.py b/django/db/backends/base/base.py
index 0356ab54cc..021fe0bafa 100644
--- a/django/db/backends/base/base.py
+++ b/django/db/backends/base/base.py
@@ -617,12 +617,11 @@ class BaseDatabaseWrapper(object):
 
     def run_and_clear_commit_hooks(self):
         self.validate_no_atomic_block()
-        try:
-            while self.run_on_commit:
-                sids, func = self.run_on_commit.pop(0)
-                func()
-        finally:
-            self.run_on_commit = []
+        current_run_on_commit = self.run_on_commit
+        self.run_on_commit = []
+        while current_run_on_commit:
+            sids, func = current_run_on_commit.pop(0)
+            func()
 
     def copy(self, alias=None, allow_thread_sharing=None):
         """
diff --git a/docs/releases/1.9.7.txt b/docs/releases/1.9.7.txt
index 5514222888..2f5555721f 100644
--- a/docs/releases/1.9.7.txt
+++ b/docs/releases/1.9.7.txt
@@ -17,3 +17,6 @@ Bugfixes
 
 * Fixed a regression causing the cached template loader to crash when using
   lazy template names (:ticket:`26603`).
+
+* Fixed ``on_commit`` callbacks execution order when callbacks make
+  transactions (:ticket:`26627`).
diff --git a/tests/transaction_hooks/tests.py b/tests/transaction_hooks/tests.py
index ebf07bc656..000de4104c 100644
--- a/tests/transaction_hooks/tests.py
+++ b/tests/transaction_hooks/tests.py
@@ -208,6 +208,20 @@ class TestConnectionOnCommit(TransactionTestCase):
 
         self.assertDone([1])
 
+    def test_hook_in_hook(self):
+        def on_commit(i, add_hook):
+            with transaction.atomic():
+                if add_hook:
+                    transaction.on_commit(lambda: on_commit(i + 10, False))
+                t = Thing.objects.create(num=i)
+                self.notify(t.num)
+
+        with transaction.atomic():
+            transaction.on_commit(lambda: on_commit(1, True))
+            transaction.on_commit(lambda: on_commit(2, True))
+
+        self.assertDone([1, 11, 2, 12])
+
     def test_raises_exception_non_autocommit_mode(self):
         def should_never_be_called():
             raise AssertionError('this function should never be called')