checkout: fix interaction between --conflict and --merge

When using "git checkout" to recreate merge conflicts or merge
uncommitted changes when switching branch "--conflict" sensibly implies
"--merge". Unfortunately the way this is implemented means that "git
checkout --conflict=diff3 --no-merge" implies "--merge" violating the
usual last-one-wins rule. Fix this by only overriding the value of
opts->merge if "--conflicts" comes after "--no-merge" or "-[-no]-merge"
is not given on the command line.

The behavior of "git checkout --merge --no-conflict" is unchanged and
will still merge on the basis that the "-[-no]-conflict" options are
primarily intended to affect the conflict style and so "--no-conflict"
should cancel a previous "--conflict" but not override "--merge".

Of the four new tests the second one tests the behavior change
introduced by this commit, the other three check that this commit does
not regress the existing behavior.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Phillip Wood 2024-03-14 17:05:07 +00:00 committed by Junio C Hamano
parent dbeaf8e8c0
commit 5a99c1ac1a
2 changed files with 67 additions and 3 deletions

View file

@ -100,7 +100,7 @@ struct checkout_opts {
struct tree *source_tree;
};
#define CHECKOUT_OPTS_INIT { .conflict_style = -1 }
#define CHECKOUT_OPTS_INIT { .conflict_style = -1, .merge = -1 }
struct branch_info {
char *name; /* The short name used */
@ -1633,6 +1633,9 @@ static int parse_opt_conflict(const struct option *o, const char *arg, int unset
opts->conflict_style = parse_conflict_style_name(arg);
if (opts->conflict_style < 0)
return error(_("unknown conflict style '%s'"), arg);
/* --conflict overrides a previous --no-merge */
if (!opts->merge)
opts->merge = -1;
return 0;
}
@ -1740,8 +1743,9 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
opts->show_progress = isatty(2);
}
if (opts->conflict_style >= 0)
opts->merge = 1; /* implied */
/* --conflicts implies --merge */
if (opts->merge == -1)
opts->merge = opts->conflict_style >= 0;
if (opts->force) {
opts->discard_changes = 1;

View file

@ -631,6 +631,66 @@ test_expect_success 'checkout --conflict=diff3' '
test_cmp merged file
'
test_expect_success 'checkout --conflict=diff3 --no-conflict does not merge' '
setup_conflicting_index &&
echo "none of the above" >expect &&
cat expect >fild &&
cat expect >file &&
test_must_fail git checkout --conflict=diff3 --no-conflict -- fild file 2>err &&
test_cmp expect file &&
test_cmp expect fild &&
echo "error: path ${SQ}file${SQ} is unmerged" >expect &&
test_cmp expect err
'
test_expect_success 'checkout --conflict=diff3 --no-merge does not merge' '
setup_conflicting_index &&
echo "none of the above" >expect &&
cat expect >fild &&
cat expect >file &&
test_must_fail git checkout --conflict=diff3 --no-merge -- fild file 2>err &&
test_cmp expect file &&
test_cmp expect fild &&
echo "error: path ${SQ}file${SQ} is unmerged" >expect &&
test_cmp expect err
'
test_expect_success 'checkout --no-merge --conflict=diff3 does merge' '
setup_conflicting_index &&
echo "none of the above" >fild &&
echo "none of the above" >file &&
git checkout --no-merge --conflict=diff3 -- fild file &&
echo "ourside" >expect &&
test_cmp expect fild &&
cat >expect <<-\EOF &&
<<<<<<< ours
ourside
||||||| base
original
=======
theirside
>>>>>>> theirs
EOF
test_cmp expect file
'
test_expect_success 'checkout --merge --conflict=diff3 --no-conflict does merge' '
setup_conflicting_index &&
echo "none of the above" >fild &&
echo "none of the above" >file &&
git checkout --merge --conflict=diff3 --no-conflict -- fild file &&
echo "ourside" >expect &&
test_cmp expect fild &&
cat >expect <<-\EOF &&
<<<<<<< ours
ourside
=======
theirside
>>>>>>> theirs
EOF
test_cmp expect file
'
test_expect_success 'checkout with invalid conflict style' '
test_must_fail git checkout --conflict=bad 2>actual -- file &&
echo "error: unknown conflict style ${SQ}bad${SQ}" >expect &&