[PATCH 3/3] add -p: disable stdin buffering when interactive.singlekey is set

From: Phillip Wood via GitGitGadget <gitgitgadget@gmail.com>
Date: Feb 16, 2022, 10:54 UTC
Message-ID: <6d8423b6e1e969ffed02b148546b88d118affd09.1645008873.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1146.git.1645008873.gitgitgadget@gmail.com>

From: Phillip Wood <phillip.wood@dunelm.org.uk>

The builtin "add -p" reads the key "F2" as three separate keys "^[", "O" and "Q". The "Q" causes it to quit which is probably not what the user was expecting. This is because it uses poll() to check for pending input when reading escape sequences but reads the input with getchar() which is buffered by default and so hoovers up all the pending input leading poll() think there isn't anything pending. Fix this by calling setbuf() to disable input buffering if interactive.singlekey is set.

Looking at the comment above mingw_getchar() in terminal.c I wonder if that function is papering over this bug and could be removed. Unfortunately I don't have access to windows to test that.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
 add-interactive.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/add-interactive.c b/add-interactive.c
index 6498ae196f1..ad78774ca26 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -70,6 +70,8 @@ void init_add_i_state(struct add_i_state *s, struct repository *r)
 			      &s->interactive_diff_algorithm);
 
 	git_config_get_bool("interactive.singlekey", &s->use_single_key);
+	if (s->use_single_key)
+		setbuf(stdin, NULL);
 }
 
 void clear_add_i_state(struct add_i_state *s)

-- 
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