On Fri, Apr 5, 2024 at 1:04 PM brian m. carlson <sandals@xxxxxxxxxxxxxxxxxxxx> wrote: > > 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: Thanks for tagging me and expounding on the testcase. Matt: sorry for taking so long to respond. This is just a quick note to say I'm aware of the bug and will respond (I think there might be a simple fix here), but for various reasons it's going to be a couple more weeks.
