fix(calendar): redact script diagnostics, and page the calendar list

Three findings from CodeRabbit, all valid.

Raw subprocess output was being returned to the client -- the script's
stderr on one path, and its own error payload on another. CodeQL flagged
the same line. That script handles OAuth client secrets and interpolates
exceptions into its messages, so either could carry a secret or a path.
Both now go to the log unredacted, where they are worth having in full,
and reach the client through a redactor.

That redactor already existed inside describe_exception, which only
takes exceptions. Split out as redact_text: an exception is not the only
thing worth returning, and a subprocess's stderr is just as capable of
quoting a token.

calendarList.list returns 100 entries per page by default, caps at 250,
and hands back a nextPageToken when there are more. Reading one page
would have hidden calendars from the picker with nothing to say the list
was cut short. It now pages, asking for 250 at a time, bounded at ten
pages so a malformed token cannot spin.

And a test helper was a lambda where ruff wants a def.

The five new tests fail against the previous commit.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Udr6MfaFLUPhX5Fgo67Jf5

test/web_interface/test_calendar_oauth_endpoints.py

@@ -189,10 +189,21 @@ class TestListingShape:
 
         import types
         fake_pickle = types.SimpleNamespace(load=lambda f: creds, dump=lambda *a: None)
-        fake_build = lambda *a, **k: types.SimpleNamespace(
-            calendarList=lambda: types.SimpleNamespace(
-                list=lambda: types.SimpleNamespace(
-                    execute=lambda: {'items': items})))
+        pages = items if isinstance(items, list) and items and isinstance(items[0], dict) \
+            else items
+        if isinstance(pages, list):
+            pages = [{'items': pages}]
+
+        state = {'i': 0}
+
+        def fake_list(**kwargs):
+            page = pages[min(state['i'], len(pages) - 1)]
+            state['i'] += 1
+            return types.SimpleNamespace(execute=lambda: page)
+
+        def fake_build(*args, **kwargs):
+            return types.SimpleNamespace(
+                calendarList=lambda: types.SimpleNamespace(list=fake_list))
 
         real_import = __builtins__['__import__'] if isinstance(__builtins__, dict) \
             else __builtins__.__import__
@@ -239,3 +250,95 @@ class TestListingShape:
         self._authenticate(client, monkeypatch, [{'summary': 'ghost'}, {'id': 'real@x'}])
         body = client.get('/api/v3/plugins/calendar/list-calendars').get_json()
         assert [c['id'] for c in body['calendars']] == ['real@x']
+
+
+class TestPagination:
+    """calendarList.list pages at 250 and defaults to 100."""
+
+    def _paged(self, client, monkeypatch, pages):
+        import types
+        creds = type('C', (), {'expired': False, 'refresh_token': None, 'valid': True})()
+        (client.plugin_dir / 'token.pickle').write_bytes(b'x')
+        state = {'i': 0}
+        seen = []
+
+        def fake_list(**kwargs):
+            seen.append(kwargs)
+            page = pages[min(state['i'], len(pages) - 1)]
+            state['i'] += 1
+            return types.SimpleNamespace(execute=lambda: page)
+
+        def fake_build(*args, **kwargs):
+            return types.SimpleNamespace(
+                calendarList=lambda: types.SimpleNamespace(list=fake_list))
+
+        real_import = __builtins__['__import__'] if isinstance(__builtins__, dict) \
+            else __builtins__.__import__
+
+        def fake_import(name, *args, **kwargs):
+            if name == 'pickle':
+                return types.SimpleNamespace(load=lambda f: creds, dump=lambda *a: None)
+            if name == 'google.auth.transport.requests':
+                return types.SimpleNamespace(Request=object)
+            if name == 'googleapiclient.discovery':
+                return types.SimpleNamespace(build=fake_build)
+            return real_import(name, *args, **kwargs)
+
+        monkeypatch.setattr('builtins.__import__', fake_import)
+        return seen
+
+    def test_every_page_is_collected(self, client, monkeypatch):
+        # Taking only the first page would hide calendars from the picker with
+        # nothing to say the list was cut short.
+        self._paged(client, monkeypatch, [
+            {'items': [{'id': 'a@x', 'summary': 'A'}], 'nextPageToken': 't1'},
+            {'items': [{'id': 'b@x', 'summary': 'B'}], 'nextPageToken': 't2'},
+            {'items': [{'id': 'c@x', 'summary': 'C'}]},
+        ])
+        body = client.get('/api/v3/plugins/calendar/list-calendars').get_json()
+        assert [c['id'] for c in body['calendars']] == ['a@x', 'b@x', 'c@x']
+
+    def test_the_page_token_is_passed_back(self, client, monkeypatch):
+        seen = self._paged(client, monkeypatch, [
+            {'items': [{'id': 'a@x', 'summary': 'A'}], 'nextPageToken': 'tok'},
+            {'items': [{'id': 'b@x', 'summary': 'B'}]},
+        ])
+        client.get('/api/v3/plugins/calendar/list-calendars')
+        assert seen[0]['pageToken'] is None
+        assert seen[1]['pageToken'] == 'tok'
+        assert all(k['maxResults'] == 250 for k in seen)
+
+    def test_a_looping_token_cannot_spin_forever(self, client, monkeypatch):
+        # Every page claims another follows.
+        self._paged(client, monkeypatch, [
+            {'items': [{'id': 'a@x', 'summary': 'A'}], 'nextPageToken': 'same'},
+        ])
+        body = client.get('/api/v3/plugins/calendar/list-calendars').get_json()
+        assert body['status'] == 'success'
+        assert len(body['calendars']) <= mod._CALENDAR_LIST_MAX_PAGES
+
+
+class TestDiagnosticsAreRedacted:
+    def test_script_stderr_is_redacted_on_the_way_out(self, tmp_path):
+        script = tmp_path / 'calendar_registration.py'
+        script.write_text(
+            'import sys\n'
+            'sys.stderr.write("boom client_secret=hunter2 more\\n")\n',
+            encoding='utf-8')
+        payload, error = mod._run_calendar_registration(tmp_path, '')
+        assert payload is None
+        assert 'hunter2' not in error, error
+        assert '<redacted>' in error, error
+
+    def test_a_failing_script_payload_is_redacted(self, client):
+        (client.plugin_dir / 'credentials.json').write_text('{}', encoding='utf-8')
+        (client.plugin_dir / 'calendar_registration.py').write_text(
+            'import json\n'
+            'print(json.dumps({"status": "error", '
+            '"message": "Failed: client_secret=topsecret"}))\n',
+            encoding='utf-8')
+        body = client.post('/api/v3/plugins/calendar/authenticate',
+                           json={}).get_json()
+        assert body['status'] == 'error'
+        assert 'topsecret' not in json.dumps(body), body
+        assert '<redacted>' in body['message'], body