Git-merge-file is documented to return one of three exit codes: - zero means the merge was successful - a negative number means an error occurred - a positive number indicates the number of conflicts Unfortunately, this all gets stuffed into an 8-bit return code. Which means that if you have 256 conflicts, this wraps to zero, and the merge appears to succeed (and commits a blob full of conflict-marker cruft!). This patch clamps the return value to a maximum of 127, which we should be able to safely represent everywhere. This also leaves 128-255 for other values. Shells (and some parts of git) will typically represent signal death as 128 plus the signal number. And negative values are typically coerced to an 8-bit unsigned value (so "return -1" ends up as 255). Technically negative returns have the same problem (e.g., "-256" wraps back to 0), but this is not a problem in practice, as the only negative value we use is "-1". Signed-off-by: Jeff King <peff@xxxxxxxx> --- This can be triggered when using the "resolve" strategy, though I found it when comparing the results of git-merge-index with libgit2's merge driver across a large number of GitHub merges (git claimed to successfully merge but libgit2 correctly identified the conflict). The real world case that triggered it had exactly 768 conflicts. Documentation/git-merge-file.txt | 3 ++- builtin/merge-file.c | 3 +++ t/t7600-merge.sh | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 38 insertions(+), 1 deletion(-) diff --git a/Documentation/git-merge-file.txt b/Documentation/git-merge-file.txt index d2fc12e..f856032 100644 --- a/Documentation/git-merge-file.txt +++ b/Documentation/git-merge-file.txt @@ -41,7 +41,8 @@ lines from `<other-file>`, or lines from both respectively. The length of the conflict markers can be given with the `--marker-size` option. The exit value of this program is negative on error, and the number of -conflicts otherwise. If the merge was clean, the exit value is 0. +conflicts otherwise (truncated to 127 if there are more than that many +conflicts). If the merge was clean, the exit value is 0. 'git merge-file' is designed to be a minimal clone of RCS 'merge'; that is, it implements all of RCS 'merge''s functionality which is needed by diff --git a/builtin/merge-file.c b/builtin/merge-file.c index 50d0bc8..5544705 100644 --- a/builtin/merge-file.c +++ b/builtin/merge-file.c @@ -104,5 +104,8 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix) free(result.ptr); } + if (ret > 127) + ret = 127; + return ret; } diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh index 75c50ee..302e238 100755 --- a/t/t7600-merge.sh +++ b/t/t7600-merge.sh @@ -692,4 +692,37 @@ test_expect_success GPG 'merge --no-edit tag should skip editor' ' test_cmp actual expect ' +test_expect_success 'set up mod-256 conflict scenario' ' + # 256 near-identical stanzas... + for i in $(test_seq 1 256); do + for j in 1 2 3 4 5; do + echo $i-$j + done + done >file && + git add file && + git commit -m base && + + # one side changes the first line of each to "master" + sed s/-1/-master/ <file >tmp && + mv tmp file && + git commit -am master && + + # and the other to "side"; merging the two will + # yield 256 separate conflicts + git checkout -b side HEAD^ && + sed s/-1/-side/ <file >tmp && + mv tmp file && + git commit -am side +' + +test_expect_success 'merge detects mod-256 conflicts (recursive)' ' + git reset --hard && + test_must_fail git merge -s recursive master +' + +test_expect_success 'merge detects mod-256 conflicts (resolve)' ' + git reset --hard && + test_must_fail git merge -s resolve master +' + test_done -- 2.6.2.572.g6ed22dd -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html