Edit's w to a file changed on disk since read is refused once, as Save is (w again to overwrite), the rest of an X/'/w written and the refused named; Edit filters get a pane command's environment ($PARDES_MOUNT, $PARDES_9P, $PARDES_PID, $winid); an Edit with no commands runs beside one whose commands run unless it touches a file that one changes, refused busy (EBUSY) as is a second Edit with commands

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

1 files changed, 21 insertions, 0 deletions

diff --git a/test/fs.py b/test/fs.py
index b593981c..f954b508 100644
--- a/test/fs.py
+++ b/test/fs.py
@@ -1123,6 +1123,27 @@ def edit_commands(binary):
             assert (root / 'b.txt').read_bytes() == b'APPLE pie\n'
             client.write(f'/pane/{a}/ctl', b'Edit 1 w first.txt\n')
             assert (root / 'first.txt').read_bytes() == b'APPLE\n'
+            # A file changed on disk under unsaved edits: Edit's w refuses
+            # once, as Save does, and the next w overwrites it.
+            w1 = root / 'w1.txt'
+            w1.write_bytes(b'one\n')
+            w = look(client, str(w1))
+            client.write(f'/pane/{w}/ctl', b'Edit $a/two/\n')
+            seen = client.read('/log').decode().count(f'\nchanged {w}')
+            with open(w1, 'ab') as f:
+                f.write(b'external\n')
+            deadline = time.monotonic() + 10
+            while client.read('/log').decode().count(f'\nchanged {w}') == seen:
+                assert time.monotonic() < deadline, 'the change on disk was not heard'
+                time.sleep(.05)
+            try:
+                client.write(f'/pane/{w}/ctl', b'Edit w\n')
+                raise AssertionError('w overwrote a file changed on disk')
+            except OSError as why:
+                assert 'modified on disk since read (w again to overwrite)' in str(why), why
+            assert w1.read_bytes() == b'one\nexternal\n'
+            client.write(f'/pane/{w}/ctl', b'Edit w\n')
+            assert w1.read_bytes() == b'one\ntwo', w1.read_bytes()
 
 
 def test(binary, quic=False):