pardes --wait (-w) in a pane returns only once the pane its file landed in is deleted, so it can be $EDITOR

A launch inside a pane forwards its file to the session's look and returned at once, so fish's Ctrl-O (edit_command_buffer), git commit and crontab -e read their still-unedited file back and went on. With --wait, as acme's E against B and read the way plan9port's E reads acme's log, it finds the pane /index names the file by (the one already showing it, if open), follows /log on one connection with 'follow new', reads /index once more to catch a Del that came first, and then blocks with no deadline until that pane's del record: exit 0, or 1 when the connection ends with the session. The 9P client's one-shot requests keep their 2 s deadline; its new follow takes it for the setup only. Outside pardes nothing changes. --help, docs/fs.md, the README and the 9P skill say to set EDITOR='pardes --wait', which GIT_EDITOR follows. Tested in fs.py (it returns within 50 ms of the Del, a second -w waits on the same pane, one whose session is killed exits 1) and end to end: fish 4.8 in a detached session, echo hi, Ctrl-O, the waiting launch idle in poll, the line edited over 9P, Save, Del, and fish ran echo edited.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 41 insertions, 0 deletions

diff --git a/test/fs.py b/test/fs.py
index 7401861b..db10f32d 100644
--- a/test/fs.py
+++ b/test/fs.py
@@ -1224,6 +1224,47 @@ def test(binary, quic=False):
                             cell[0] for cell in local.screen()['cells'])
                     assert client.read('/index') == before
 
+        # --wait (acme's E): a launch inside a pane lasts until the pane it
+        # opened is deleted, as an $EDITOR must; one on a file already open
+        # waits on that pane; a session that goes away ends it with 1.
+        with session(binary, root, 'wait') as (client, address):
+            status = dict(line.split(maxsplit=1) for line in client.read('/status').decode().splitlines())
+            env = {k: v for k, v in os.environ.items() if k != 'PARDES_FORWARD_LOOK'}
+            env.update(PARDES_9P=str(address), PARDES_PANE='1', PARDES_PID=status['pid'])
+            edited = root / 'wait edit.txt'
+            edited.write_bytes(b'edit me\n')
+
+            def serials():
+                return {int(row.split()[0]) for row in client.read('/index').splitlines()}
+
+            def launch(flag):
+                before = serials()
+                child = subprocess.Popen([binary, flag, str(edited)], cwd=root, env=env,
+                                         stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
+                deadline = time.monotonic() + 3
+                while child.poll() is None and not serials() - before and time.monotonic() < deadline:
+                    time.sleep(.01)
+                return child
+
+            first = launch('--wait')
+            opened, = serials() - {1}
+            second = launch('-w')
+            time.sleep(.5)
+            assert first.poll() is None and second.poll() is None, (first.stderr.read(), second.stderr.read())
+            assert serials() == {1, opened}
+            client.write(f'/pane/{opened}/body', b'edited\n', truncate=True)
+            execute(client, opened, 'Save')
+            client.remove(f'/pane/{opened}')
+            deleted = time.monotonic()
+            assert first.wait(timeout=5) == 0
+            # Woken by the `del` record, not a poll.
+            assert time.monotonic() - deleted < .05, time.monotonic() - deleted
+            assert second.wait(timeout=5) == 0
+            assert edited.read_bytes() == b'edited\n'
+            orphan = launch('--wait')
+            assert orphan.poll() is None
+        assert orphan.wait(timeout=5) == 1
+
         for tty in [False, True]:
             name = 'lsp-tty' if tty else 'lsp-detached'
             with session(binary, root, name, tty=tty) as (client, _):