Save makes the directories its file goes in, always: for the pane's own name and Save path alike

Whether a Save made missing directories depended on how the name had
come about. Config's pane did, a name written into a missing directory did
(since kkrqxtsp), and `Save path` and every other name did not, failing
ENOENT instead. There is now one rule: a Save makes the parent
directories of the file it writes, a pane's own or a terminal's
scrollback included, and the make_dirs flag is gone. A directory it
cannot make still fails the write with why, as fs.py's
/nonexistent-pardes-dir case shows. fs.py now also saves into missing
directories by Save path and by a written name.

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

1 files changed, 12 insertions, 2 deletions

diff --git a/test/fs.py b/test/fs.py
index a1e2ae79..b02b9e45 100644
--- a/test/fs.py
+++ b/test/fs.py
@@ -381,8 +381,18 @@ def discovery(binary, embedded=False):
             # Through a mount both read as EINVAL; the log says which and why.
             assert f'err {scratch} addr: no match for regexp\n'.encode() in client.read('/log')
             client.remove(f'/pane/{scratch}')
-            # A save the host cannot do fails the write that asked for it,
-            # and the log's err record names the path and why.
+            # A Save makes the directories its file goes in, whatever names
+            # it: the pane's own name or Save's path.
+            made_dirs = new_pane(client, b'deep\n')
+            client.write(f'/pane/{made_dirs}/ctl', f'Save {root}/save-made/a/b/x.txt\n'.encode())
+            assert (root / 'save-made/a/b/x.txt').read_bytes() == b'deep\n'
+            client.write(f'/pane/{made_dirs}/name', f'{root}/save-named/c/y.txt\n'.encode())
+            client.write(f'/pane/{made_dirs}/ctl', b'Save\n')
+            assert (root / 'save-named/c/y.txt').read_bytes() == b'deep\n'
+            client.remove(f'/pane/{made_dirs}')
+            # A save the host cannot do (a directory it may not make) fails
+            # the write that asked for it, and the log's err record names
+            # the path and why.
             unsaved = new_pane(client, b'unsaved\n')
             try:
                 client.write(f'/pane/{unsaved}/ctl', b'Save /nonexistent-pardes-dir/x.txt\n')