pardes - keeps one +Pager per directory, refilled, named so from its first log record; streams the text in bounded writes; never loses it; handles \r, NUL and BEL as a terminal does

Each paged command made another +Pager until placement failed, and
then git's text was lost with exit 0; a 130 MB page timed out half
written and dirty; a directory whose name held a newline left a stray
+New; and the log said new +New then rename. The root ctl's `pager
<dir>` now makes the directory's +Pager (named before it is announced,
placed without the keyboard) or empties the one there; the text goes
into it a line-ended 8 MiB chunk a write, one undo step, up to the file
limit and its note, and is left clean. A directory a ctl line cannot
name pages into the session's. Any failure prints the text to stderr
with why and exits 1. A carriage return keeps a progress line's last
state and CRLF is a newline; NUL, BEL, SO and SI go; empty stdin makes
no pane.

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 fce315fc..b2f52c3e 100644
--- a/test/fs.py
+++ b/test/fs.py
@@ -1456,7 +1456,32 @@ def test(binary, quic=False):
             assert client.read(f'/pane/{made_now}/body') == b'bold text\n'
             row = [r for r in client.read('/index').splitlines() if r.split()[0] == str(made_now).encode()][0]
             assert row.split()[2] == b'0', row  # clean: nothing to ask at Exit
+            # Its `new` record names it as it is: no +New and a rename.
+            log_now = client.read('/log').decode()
+            assert f'\nnew {made_now} {root}/+Pager\n' in '\n' + log_now, log_now[-400:]
+            assert f'\nrename {made_now} ' not in '\n' + log_now
+            # The directory's one +Pager: the next paged text refills it.
+            fed = subprocess.run([binary, '-'], cwd=root, env=env, input=b'again\r\nprogress 10%\rprogress 100%\n',
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE, timeout=10)
+            assert fed.returncode == 0, fed.stderr
+            assert serials() - before == {made_now}, (serials(), before)
+            assert client.read(f'/pane/{made_now}/body') == b'again\nprogress 100%\n'
             client.remove(f'/pane/{made_now}')
+            # From a directory whose name could not be a ctl line: the
+            # session's directory's +Pager, the text whole, no stray +New.
+            odd = root / 'two\nlines'
+            odd.mkdir()
+            fed = subprocess.run([binary, '-'], cwd=odd, env=env, input=b'odd dir text\n',
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE, timeout=10)
+            assert fed.returncode == 0, fed.stderr
+            odd_pane, = serials() - before
+            assert client.read(f'/pane/{odd_pane}/name') == f'{root}/+Pager\n'.encode()
+            assert client.read(f'/pane/{odd_pane}/body') == b'odd dir text\n'
+            client.remove(f'/pane/{odd_pane}')
+            # Nothing on stdin: no pane, and done.
+            fed = subprocess.run([binary, '-'], cwd=root, env=env, input=b'',
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE, timeout=10)
+            assert fed.returncode == 0 and serials() == before, (fed, serials())
             # A new name in a directory there but not writable: refused now,
             # not a pane that only fails at Save.
             shut = root / 'shut-dir'