Merge branch 'main' into changelog-changes

CHANGES.md

@@ -11,6 +11,7 @@
 * More robust validation of observer signatures (#1147)
 * Change `Model.relation.app` type from `Application|None` to `Application` (#1151)
 * Fix attaching storage in Harness before `begin` (#1150)
+* Fixed an issue where `pebble.Client.exec` might leak a `socket.timeout` (`builtins.TimeoutError`) exception (#1155)
 
 ## Refactoring
 

ops/pebble.py

@@ -18,6 +18,7 @@
 """
 
 import binascii
+import builtins
 import copy
 import dataclasses
 import datetime
@@ -1722,6 +1723,11 @@ class Client:
     connecting to or transferring data with Pebble will raise a :class:`ConnectionError`. When an
     error occurs executing the request, such as trying to add an invalid layer or execute a command
     that does not exist, an :class:`APIError` is raised.
+
+    The ``timeout`` parameter specifies a timeout in seconds for blocking operations like the
+    connection attempt to Pebble; used by ``urllib.request.OpenerDirector.open``. It's not for
+    methods like :meth:`start_services` and :meth:`replan_services` mentioned above, and it's not
+    for the command execution timeout defined in method :meth:`Client.exec`.
     """
 
     _chunk_size = 8192
@@ -2029,8 +2035,10 @@ def _wait_change_using_wait(self, change_id: ChangeID, timeout: Optional[float])
 
             try:
                 return self._wait_change(change_id, this_timeout)
-            except TimeoutError:
-                # Catch timeout from wait endpoint and loop to check deadline
+            except (socket.timeout, builtins.TimeoutError):
+                # NOTE: in Python 3.10 socket.timeout is an alias of TimeoutError,
+                # but we still need to support Python 3.8, so catch both.
+                # Catch timeout from wait endpoint and loop to check deadline.
                 pass
 
         raise TimeoutError(f'timed out waiting for change {change_id} ({timeout} seconds)')

test/test_pebble.py

@@ -18,6 +18,7 @@
 import io
 import json
 import signal
+import socket
 import tempfile
 import test.fake_pebble as fake_pebble
 import typing
@@ -2028,6 +2029,18 @@ def test_wait_change_error(self):
             ('GET', '/v1/changes/70/wait', {'timeout': '4.000s'}, None),
         ])
 
+    def test_wait_change_socket_timeout(self):
+        def timeout_response(n: float):
+            self.time.sleep(n)
+            raise socket.timeout("socket.timeout: timed out")
+
+        self.client.responses.append(lambda: timeout_response(3))
+
+        with self.assertRaises(pebble.TimeoutError) as cm:
+            self.client.wait_change(pebble.ChangeID('70'), timeout=3)
+        self.assertIsInstance(cm.exception, pebble.Error)
+        self.assertIsInstance(cm.exception, TimeoutError)
+
     def test_add_layer(self):
         okay_response = {
             "result": True,