From 2b7b788fb31a74bcbff4e4c6efc6f3db6c3a49b7 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 22 Jun 2023 17:33:01 -0700 Subject: ll-merge: killing the external merge driver aborts the merge When an external merge driver dies with a signal, we should not expect that the result left on the filesystem is in any useful state. However, because the current code uses the return value from run_command() and declares any positive value as a sign that the driver successfully left conflicts in the result, and because the return value from run_command() for a subprocess that died upon a signal is positive, we end up treating whatever garbage left on the filesystem as the result the merge driver wanted to leave us. run_command() returns larger than 128 (WTERMSIG(status) + 128, to be exact) when it notices that the subprocess died with a signal, so detect such a case and return LL_MERGE_ERROR from ll_ext_merge(). Signed-off-by: Junio C Hamano Reviewed-by: Elijah Newren --- Documentation/gitattributes.txt | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 02a3ec83e4..6deb89a296 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -1132,7 +1132,10 @@ size (see below). The merge driver is expected to leave the result of the merge in the file named with `%A` by overwriting it, and exit with zero status if it managed to merge them cleanly, or non-zero if there -were conflicts. +were conflicts. When the driver crashes (e.g. killed by SEGV), +it is expected to exit with non-zero status that are higher than +128, and in such a case, the merge results in a failure (which is +different from producing a conflict). The `merge.*.recursive` variable specifies what other merge driver to use when the merge driver is called for an internal -- cgit v1.3-5-g9baa