Fix a segfault in the --set-upstream option added in 24bc1a12926 (pull, fetch: add --set-upstream option, 2019-08-19) added in v2.24.0. The code added there did not do the same checking we do for "git branch" itself since 8efb8899cfe (branch: segfault fixes and validation, 2013-02-23), which in turn fixed the same sort of segfault I'm fixing now in "git branch --set-upstream-to", see 6183d826ba6 (branch: introduce --set-upstream-to, 2012-08-20). The warning message I'm adding here is an amalgamation of the error added for "git branch" in 8efb8899cfe, and the error output install_branch_config() itself emits, i.e. it trims "refs/heads/" from the name and says "branch X on remote", not "branch refs/heads/X on remote". I think it would make more sense to simply die() here, but in the other checks for --set-upstream added in 24bc1a12926 we issue a warning() instead. Let's do the same here for consistency for now. There was an earlier submitted alternate way of fixing this in [1], due to that patch breaking threading with the original report at [2] I didn't notice it before authoring this version. I think the more detailed warning message here is better, and we should also have tests for this behavior. 1. https://lore.kernel.org/git/20210706162238.575988-1-clemens@xxxxxxxxxxxxx/ 2. https://lore.kernel.org/git/CAG6gW_uHhfNiHGQDgGmb1byMqBA7xa8kuH1mP-wAPEe5Tmi2Ew@xxxxxxxxxxxxxx/ Reported-by: Clemens Fruhwirth <clemens@xxxxxxxxxxxxx> Reported-by: Jan Pokorný <poki@xxxxxxxx> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> --- A v3 that functionally behaves the same way, but uses a more idiomatic way of calling skip_prefix() to strip the "refs/heads/*" prefix, if present. Range-diff against v2: 1: 9e846b76959 ! 1: 68899471206 pull, fetch: fix segfault in --set-upstream option @@ builtin/fetch.c: static int do_fetch(struct transport *transport, } if (source_ref) { + if (!branch) { -+ const char *shortname = NULL; -+ if (!skip_prefix(source_ref->name, -+ "refs/heads/", &shortname)) -+ shortname = source_ref->name; ++ const char *shortname = source_ref->name; ++ skip_prefix(shortname, "refs/heads/", &shortname); ++ + warning(_("could not set upstream of HEAD to '%s' from '%s' when " + "it does not point to any branch."), + shortname, transport->remote->name); builtin/fetch.c | 10 ++++++++++ t/t5553-set-upstream.sh | 22 ++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/builtin/fetch.c b/builtin/fetch.c index e064687dbdc..28fa168133a 100644 --- a/builtin/fetch.c +++ b/builtin/fetch.c @@ -1625,6 +1625,16 @@ static int do_fetch(struct transport *transport, } } if (source_ref) { + if (!branch) { + const char *shortname = source_ref->name; + skip_prefix(shortname, "refs/heads/", &shortname); + + warning(_("could not set upstream of HEAD to '%s' from '%s' when " + "it does not point to any branch."), + shortname, transport->remote->name); + goto skip; + } + if (!strcmp(source_ref->name, "HEAD") || starts_with(source_ref->name, "refs/heads/")) install_branch_config(0, diff --git a/t/t5553-set-upstream.sh b/t/t5553-set-upstream.sh index b1d614ce18c..7d12ceff702 100755 --- a/t/t5553-set-upstream.sh +++ b/t/t5553-set-upstream.sh @@ -91,6 +91,17 @@ test_expect_success 'fetch --set-upstream with valid URL sets upstream to URL' ' check_config_missing other2 ' +test_expect_success 'fetch --set-upstream with a detached HEAD' ' + git checkout HEAD^0 && + test_when_finished "git checkout -" && + cat >expect <<-\EOF && + warning: could not set upstream of HEAD to '"'"'main'"'"' from '"'"'upstream'"'"' when it does not point to any branch. + EOF + git fetch --set-upstream upstream main 2>actual.raw && + grep ^warning: actual.raw >actual && + test_cmp expect actual +' + # tests for pull --set-upstream test_expect_success 'setup bare parent pull' ' @@ -178,4 +189,15 @@ test_expect_success 'pull --set-upstream with valid URL and branch sets branch' check_config_missing other2 ' +test_expect_success 'pull --set-upstream with a detached HEAD' ' + git checkout HEAD^0 && + test_when_finished "git checkout -" && + cat >expect <<-\EOF && + warning: could not set upstream of HEAD to '"'"'main'"'"' from '"'"'upstream'"'"' when it does not point to any branch. + EOF + git pull --set-upstream upstream main 2>actual.raw && + grep ^warning: actual.raw >actual && + test_cmp expect actual +' + test_done -- 2.33.0.741.g4db85f1eb27
