From 5be703b6c705739ea43cf3bde2625ada629a1218 Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 30 Apr 2024 10:38:52 -0400 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. This NULL reference appears to be due to the way the loop is abusing the the_repository pointer, pointing it to a local repository struct after discovering that the current directory is a valid Git repository. This repo-swapping bit was in the original implementation from 4582676075 (scalar: teach 'reconfigure' to optionally handle all registered enlistments, 2021-12-03), but only recently started segfaulting while trying to parse the HEAD reference. This also only happens on the _second_ repository in the list, so does not reproduce if there is only one registered repo. 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 --- scalar.c | 10 +++++++--- t/t9210-scalar.sh | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 3 deletions(-) diff --git a/scalar.c b/scalar.c index fb2940c2a00c94..7234049a1b87c0 100644 --- a/scalar.c +++ b/scalar.c @@ -645,7 +645,6 @@ 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, @@ -665,6 +664,7 @@ 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); @@ -712,13 +712,17 @@ 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) 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 428339e342751e..a41b4fcc0859db 100755 --- a/t/t9210-scalar.sh +++ b/t/t9210-scalar.sh @@ -180,6 +180,44 @@ test_expect_success 'scalar reconfigure' ' test true = "$(git -C one/src config core.preloadIndex)" ' +test_expect_success 'scalar reconfigure --all with includeIf.onbranch' ' + repos="two three four" && + for num in $repos + do + git init $num/src && + scalar register $num/src && + git -C $num/src config includeif."onbranch:foo".path something && + git -C $num/src config core.preloadIndex false || return 1 + done && + + scalar reconfigure --all && + + for num in $repos + do + test true = "$(git -C $num/src config core.preloadIndex)" || return 1 + done +' + + test_expect_success 'scalar reconfigure --all with detached HEADs' ' + repos="two three four" && + for num in $repos + do + rm -rf $num/src && + git init $num/src && + scalar register $num/src && + git -C $num/src config core.preloadIndex false && + test_commit -C $num/src initial && + git -C $num/src switch --detach HEAD || return 1 + done && + + scalar reconfigure --all && + + for num in $repos + do + test true = "$(git -C $num/src config core.preloadIndex)" || return 1 + done +' + test_expect_success '`reconfigure -a` removes stale config entries' ' git init stale/src && scalar register stale &&