Hi James
On 17/06/2025 19:56, James Duley via GitGitGadget wrote:
From: James Duley <jagduley@xxxxxxxxx>
Previously, if save_term/restore_term was called with the DUPLEX flag
and then without the flag, an assertion was hit.
Assertion failed: hconout != INVALID_HANDLE_VALUE,
file compat/terminal.c, line 283
This is because save_term doesn't set cmode_out when not DUPLEX,
so an old version of cmode_out was being used.
Therefore, hconout is the correct thing for restore to check
to decide whether to restore stdout console mode.
I found this paragraph (especially the first sentence) rather hard to
understand - it was only after I'd figured out what the problem was by
reading the code that I could understand what it was saying.
As I understand it the problem is caused by calling
save_term(SAVE_TERM_DUPLEX);
restore_term();
save_term(0);
restore_term();
The first call to save_term() sets hconout to a valid handle and
cmode_out to a non-zero value. The first call to restore_term() then
sets hconout to INVALID_HANDLE_VALUE but leaves cmode_out unchanged. The
second call to save_term does not touch hconout or cmode_out. The second
call to restore_term() then hits the assertion because cmode_out is
non-zero but hconout is an invalid handle.
I think it would be helpful to include an explanation like that in the
commit message.
I agree with you diagnosis and the proposed fix - using the filehandle
to tell whether we should restore the output settings is much cleaner
that looking at the mode. I would suggest that we should also set
hconout to INVALID_HANDLE_VALUE when save_term() is called without
SAVE_TERM_DUPLEX to avoid any problems with call sequences like
save_term(SAVE_TERM_DUPLEX);
save_term(0);
restore_term();
Thanks for reporting and working on this
Phillip
I saw this on Windows with interactive.singleKey when doing `git add -p`.
Specifically, after hitting `e` to edit in vim, once on to the prompt
for the next hunk, pressing any key results in the assertion.
Signed-off-by: James Duley <jagduley@xxxxxxxxx>
---
Ensure restore_term works correctly with DUPLEX
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2000%2Fparched%2Frestore-term-windows-fix-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2000/parched/restore-term-windows-fix-v1
Pull-Request: https://github.com/git/git/pull/2000
compat/terminal.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/compat/terminal.c b/compat/terminal.c
index 584f27bf7e1..72b184555ff 100644
--- a/compat/terminal.c
+++ b/compat/terminal.c
@@ -279,8 +279,7 @@ void restore_term(void)
SetConsoleMode(hconin, cmode_in);
CloseHandle(hconin);
- if (cmode_out) {
- assert(hconout != INVALID_HANDLE_VALUE);
+ if (hconout != INVALID_HANDLE_VALUE) {
SetConsoleMode(hconout, cmode_out);
CloseHandle(hconout);
}
base-commit: 16bd9f20a403117f2e0d9bcda6c6e621d3763e77
