[PATCH v3] branch: do not fail a no-op --edit-desc
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Sep 30, 2022, 18:06 UTC
- Message-ID
- <xmqqmtagka8x.fsf@gitster.g>
- In-Reply-To
- <xmqq8rm1mz1d.fsf@gitster.g>
Imagine running "git branch --edit-description" while on a branch without the branch description, and then exit the editor after emptying the edit buffer, which is the way to tell the command that you changed your mind and you do not want the description after all.
The command should just happily oblige, adding no branch description for the current branch, and exit successfully. But it fails to do so:
$ git init -b main
$ git commit --allow-empty -m commit
$ GIT_EDITOR=: git branch --edit-description
fatal: could not unset 'branch.main.description'The end result is OK in that the configuration variable does not exist in the resulting repository, but we should do better. If we know we didn't have a description, and if we are asked not to have a description by the editor, we can just return doing nothing.
This of course introduces TOCTOU. If you add a branch description to the same branch from another window, while you had the editor open to edit the description, and then exit the editor without writing anything there, we'd end up not removing the description you added in the other window. But you are fooling yourself in your own repository at that point, and if it hurts, you'd be better off not doing so ;-).
Signed-off-by: Junio C Hamano <gitster@pobox.com> --- * Ævar reports that CONFIG_NOTHING_SET is not a usable error status for this purpose, unfortunately. So let's go back to the approach taken by the initial implementation, but with the proposed log message clarified.
builtin/branch.c | 6 ++++-- t/t3200-branch.sh | 3 +++ 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/builtin/branch.c b/builtin/branch.c index 8c0b428104..ae08147572 100644 --- a/builtin/branch.c +++ b/builtin/branch.c @@ -576,10 +576,11 @@ static GIT_PATH_FUNC(edit_description, "EDIT_DESCRIPTION") static int edit_branch_description(const char *branch_name) { + int exists; struct strbuf buf = STRBUF_INIT; struct strbuf name = STRBUF_INIT; - read_branch_desc(&buf, branch_name); + exists = !read_branch_desc(&buf, branch_name); if (!buf.len || buf.buf[buf.len-1] != '\n') strbuf_addch(&buf, '\n'); strbuf_commented_addf(&buf, @@ -596,7 +597,8 @@ static int edit_branch_description(const char *branch_name) strbuf_stripspace(&buf, 1); strbuf_addf(&name, "branch.%s.description", branch_name); - git_config_set(name.buf, buf.len ? buf.buf : NULL); + if (buf.len || exists) + git_config_set(name.buf, buf.len ? buf.buf : NULL); strbuf_release(&name); strbuf_release(&buf); diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh index 3ec3e1d730..30dff9e712 100755 --- a/t/t3200-branch.sh +++ b/t/t3200-branch.sh @@ -1268,6 +1268,9 @@ test_expect_success 'attempt to delete a branch merged to its base' ' ' test_expect_success 'use --edit-description' ' + EDITOR=: git branch --edit-description && + test_must_fail git config branch.main.description && + write_script editor <<-\EOF && echo "New contents" >"$1" EOF
-- 2.38.0-rc2-134-gd449533db0