On 2024-04-04 at 16:16:05, Matt Cree wrote: > Hello all. I have observed some strange behaviour when exiting a custom merge driver that I was wondering if there’s any reason for — I think it may be a bug but I’ll leave that to you to decide. > > I’m configuring that merge driver to exit during a merge at the first sign of conflicts — the exact nature of the rules for the decision to exit early isn’t too important I think though so given it’s ‘work stuff’ I’ll leave some details out. > > Here is my current understanding of how the ort strategy will deal with this. > > - Ort runs the merge driver with the parameters for the current file to be merged > - When the driver returns exit code 0 is returned it is treated as having no conflicts > - When the driver returns exit code 1-128 is returned it is treated as having conflicts > - When the driver returns exit code 129+ is returned it is treated as some kind of error scenario > > > Then subsequently > - If all files returned exit code 0 during the merge git will return exit code 0 i.e. no conflicts > - If any file returned exit code 1-128 during the merge git will return exit code 1 i.e. conflicts > - At any time if the driver returns 129+, git will stop merging and return exit code 2 i.e. error? > > However, when setting up a criss-cross merge scenario and ‘short circuiting’ the merge during an ancestor merge, I get exit code 134 > > Here’s a couple of quick scripts that help recreate the situation https://gist.github.com/mattcree/c6d8cc95f41e30b5d7467e9d2b01cd3d Thanks for the repro steps. I'm on Debian, which uses dash as /bin/sh, and I also use a different default branch (dev), so I was able to reproduce with the following patch applied: ---- diff --git a/init-repo.sh b/init-repo.sh old mode 100644 new mode 100755 index e0f42a4..25d7f25 --- a/init-repo.sh +++ b/init-repo.sh @@ -1,5 +1,5 @@ rm -rf merge-driver-test mkdir merge-driver-test cd merge-driver-test -git init . +git init -b master . git commit --allow-empty -m "Initial" \ No newline at end of file diff --git a/run-merge.sh b/run-merge.sh old mode 100644 new mode 100755 diff --git a/run-recursive-merge.sh b/run-recursive-merge.sh old mode 100644 new mode 100755 index 6920720..c63d652 --- a/run-recursive-merge.sh +++ b/run-recursive-merge.sh @@ -1,3 +1,5 @@ +#!/bin/sh + cd merge-driver-test current_time=$(date "+%Y%m%d-%H%M%S"); @@ -12,7 +14,7 @@ featureA="$current_time-feature-a"; featureB="$current_time-feature-b"; featureC="$current_time-feature-c"; -function writeFiles() { +writeFiles() { cat > $xmlFileName << EOM <?xml version="1.0" encoding="UTF-8"?> <CustomLabels xmlns="http://soap.sforce.com/2006/04/metadata";> ---- I take it from the "Abort trap" message below, you're on macOS, but I don't think that's relevant to reproduction. > The logs also show > > ``` > Assertion failed: (opt->priv == NULL), function merge_switch_to_result, file merge-ort.c, line 4661. ./run-recursive-merge.sh: line 162: 78797 Abort trap: 6 git merge $featureC --no-ff --no-commit > ``` This is definitely a bug because we triggered an assertion. The assertion asserts that that case will never happen, so if it does, we've made a mistake in our code. This also explains the 134 exit status, because on most Unix systems, `SIGABRT` is signal 6, and when a program exits with a signal, the shell returns an exit status of 128 plus the signal number. Because a failed assertion calls `abort`, which raises `SIGABRT`, that would lead to an exit status in the shell of 134. I've CC'd Elijah Newren, who's the author of merge-ort and who wrote the code. I'm not familiar at all with merge-ort, so I can't speak to what might be going wrong here. -- brian m. carlson (they/them or he/him) Toronto, Ontario, CA
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