add -p: disable stdin buffering when interactive.singlekey is set

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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/add-interactive.c b/add-interactive.c
index 6498ae196f1e1ed34001e2da87d64defa64c8507..ad78774ca2623d402511b77ad612f862fb76af38 100644 (file)
--- 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)