From 48fc3b0292f7483d23eb4d8353da82e40e3d77d3 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Wed, 8 May 2024 00:05:49 +0000 Subject: [PATCH] scalar: avoid segfault in reconfigure --all During the latest v2.45.0 update, 'scalar reconfigure --all' started to segfault on my machine. Breaking it down via the debugger, it was faulting on a NULL reference to the_hash_algo, which is a macro pointing to the_repository->hash_algo. In my case, this is due to one of my repositories having a detached HEAD, which requires get_oid_hex() to parse that the HEAD reference is valid. Another way to cause a failure is to use the "includeIf.onbranch" config key, which will lead to a BUG() statement. My first inclination was to try to refactor cmd_reconfigure() to execute 'git for-each-repo' instead of this loop. In addition to the difficulty of executing 'scalar reconfigure' within 'git for-each-repo', it would be difficult to perform the clean-up logic for non-existent repos if we relied on that child process. Instead, I chose to move the temporary repo to be within the loop and reinstate the_repository to its old value after we are done performing logic on the current array item. Add tests to t9210-scalar.sh to test 'scalar reconfigure --all' with multiple registered repos. There are two different ways that the old use of the_repository could trigger bugs. These issues are being solved independently to be more careful about the_repository being uninitialized, but the change in this patch around the use of the_repository is still a good safety precaution. Co-authored-by: Patrick Steinhardt Signed-off-by: Patrick Steinhardt Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- scalar.c | 10 +++++++--- t/t9210-scalar.sh | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 3 deletions(-) diff --git a/scalar.c b/scalar.c index d54afb9572e8fa..68ed2e8bd8a9a3 100644 --- a/scalar.c +++ b/scalar.c @@ -1028,7 +1028,6 @@ static int cmd_reconfigure(int argc, const char **argv) }; struct string_list scalar_repos = STRING_LIST_INIT_DUP; int i, res = 0; - struct repository r = { NULL }; struct strbuf commondir = STRBUF_INIT, gitdir = STRBUF_INIT; argc = parse_options(argc, argv, NULL, options, @@ -1048,6 +1047,7 @@ static int cmd_reconfigure(int argc, const char **argv) for (i = 0; i < scalar_repos.nr; i++) { int succeeded = 0; + struct repository *old_repo, r = { NULL }; const char *dir = scalar_repos.items[i].string; strbuf_reset(&commondir); @@ -1095,14 +1095,18 @@ static int cmd_reconfigure(int argc, const char **argv) git_config_clear(); + if (repo_init(&r, gitdir.buf, commondir.buf)) + goto loop_end; + + old_repo = the_repository; the_repository = &r; - r.commondir = commondir.buf; - r.gitdir = gitdir.buf; if (set_recommended_config(1) >= 0 && toggle_maintenance(1) >= 0) succeeded = 1; + the_repository = old_repo; + loop_end: if (!succeeded) { res = -1; diff --git a/t/t9210-scalar.sh b/t/t9210-scalar.sh index 1a604409eaeb33..2c3445a91ba1a1 100755 --- a/t/t9210-scalar.sh +++ b/t/t9210-scalar.sh @@ -190,6 +190,44 @@ test_expect_success 'scalar reconfigure' ' test_subcommand git maintenance start