A path with a part over 255 bytes is refused, never a panic

std's statFile takes the kernel's ENAMETOOLONG for a bug (errnoBug), so a name, look, DumpDir or Save path with a part over 255 bytes panicked the editor (exec.kindOf via writeName, recentKeeps, dumpFailed). Every non-test statFile now goes through fs.statPath, which refuses such a name as NameTooLong first; fs.py drives long, looping, not-a-directory and not-ours paths through name, look, DumpDir, Dump and Save.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/test/fs.py b/test/fs.py
index 75d03d40..a025ec47 100644
--- a/test/fs.py
+++ b/test/fs.py
@@ -814,6 +814,30 @@ def signal_cleans_up(binary):
                 assert not address.exists() and not detached.exists(), (sig, list(root.iterdir()))
 
 
+def odd_paths(binary):
+    """Long and odd paths written where a path goes -- name, look, DumpDir,
+    Dump, Save -- are refused or said, never a crash: a part over 255 bytes
+    (ENAMETOOLONG), a loop of links (ELOOP), a file taken for a directory
+    (ENOTDIR), one not ours (EACCES)."""
+    with tempfile.TemporaryDirectory(prefix='pardes-odd-') as directory:
+        root = Path(directory)
+        (root / 'loop').symlink_to(root / 'loop')
+        (root / 'plain').write_bytes(b'x\n')
+        odd = ['/tmp/' + 'x' * 300 + '/f.txt', str(root / ('y' * 300)), str(root / 'loop' / 'f'),
+               str(root / 'plain' / 'f'), '/root/nope/f', str(root / 'a' / '..' / 'b.txt')]
+        with session(binary, root, 'odd') as (client, _):
+            serial = new_pane(client, b'text\n')
+            for path in odd:
+                for where, line in ((f'/pane/{serial}/name', path), ('/look', path),
+                                    ('/ctl', f'DumpDir {path}'), ('/ctl', 'Dump'), (f'/pane/{serial}/ctl', 'Save')):
+                    try:
+                        client.write(where, (line + '\n').encode())
+                    except OSError:
+                        pass
+                    assert client.read('/index'), (where, line)
+            client.write('/ctl', b'DumpDir\n')
+
+
 def cut_writes(binary):
     """A write bigger than a 9P message comes as several, cut anywhere: each
     command line runs once, whole, an Edit block once it ends, and a last
@@ -846,6 +870,7 @@ def cut_writes(binary):
 def test(binary, quic=False):
     started = time.monotonic()
     cut_writes(binary)
+    odd_paths(binary)
     run_file(binary)
     exit_answers(binary)
     unattended_messages_expire(binary)