Hi Jinoh,
On Fri, 6 Nov 2020, Jinoh Kang wrote:
> Commit 3aef54e8b8 ("diff: munmap() file contents before running external
> diff") introduced calls to diff_free_filespec_data in
> run_external_diff, which may pass NULL pointers.
Sorry for the breakage!
Maybe the commit message could talk a bit about the circumstances when
this happens? Of course, I (and every other reader...) could analyze your
patch to guess what it is that triggers the bug, but it's really a good
use of the commit message to describe it in plain English.
>
> Fix this and prevent any such bugs in the future by making
> `diff_free_filespec_data(NULL)` a no-op.
>
> Fixes: 3aef54e8b8 ("diff: munmap() file contents before running external diff")
I am unaware of any other commit having a `Fixes:` trailer in the commit
message. In any case, I would have expected `Fixes:` to mention a ticket
or a bug report, not the commit that fixed _a separate_ issue (but
unfortunately introduced this regression).
> Signed-off-by: Jinoh Kang <luke1337@xxxxxxxxx>
> ---
> diff.c | 3 +++
> t/t7800-difftool.sh | 23 +++++++++++++++++++++++
> 2 files changed, 26 insertions(+)
>
> diff --git a/diff.c b/diff.c
> index d24f47df99..ace4a1d387 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -4115,6 +4115,9 @@ void diff_free_filespec_blob(struct diff_filespec *s)
>
> void diff_free_filespec_data(struct diff_filespec *s)
> {
> + if (!s)
> + return;
> +
> diff_free_filespec_blob(s);
> FREE_AND_NULL(s->cnt_data);
We can write this in a more canonical way without wasting all that many
lines:
if (s) {
diff_free_filespec_blob(s);
FREE_AND_NULL(s->cnt_data);
}
> }
> diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
> index 524f30f7dc..e9391abb54 100755
> --- a/t/t7800-difftool.sh
> +++ b/t/t7800-difftool.sh
> @@ -728,6 +728,29 @@ test_expect_success 'add -N and difftool -d' '
> git difftool --dir-diff --extcmd ls
> '
>
> +test_expect_success 'difftool --cached with unmerged files' '
> + test_when_finished git reset --hard &&
> + echo base >file &&
> + git add file &&
> + git commit -m base &&
This does not advance the committer date. Let's just use the helper
function we invented to make this much easier:
test_commit base
This has also the advantage of already tagging the outcome.
> + git checkout -B conflict-a &&
> + git checkout -B conflict-b &&
> + git checkout conflict-a &&
> + echo conflict-a >>file &&
> + git add file &&
> + git commit -m conflict-a &&
> + git checkout conflict-b &&
> + echo conflict-b >>file &&
> + git add file &&
> + git commit -m conflict-b &&
> + git checkout master &&
> + git merge conflict-a &&
> + test_must_fail git merge conflict-b &&
> + : >expect &&
> + git difftool --cached --no-prompt >actual &&
> + test_cmp expect actual
Shouldn't this use the `test_must_be_empty` function instead?
How about writing the test case this way:
test_expect_success 'difftool --cached with unmerged files' '
test_when_finished git reset --hard &&
test_commit conflicting &&
test_commit conflict-a a conflicting.t &&
git reset --hard conflicting &&
test_commit conflict-b b conflicting.t &&
test_must_fail git merge conflict-a &&
git difftool --cached --no-prompt >out &&
test_must_be_empty out
'
Ciao,
Dscho
> +'
> +
> test_expect_success 'outside worktree' '
> echo 1 >1 &&
> echo 2 >2 &&
> --
> 2.26.2
>
>
