They could be missing due to an interrupted git-annex at just the wrong
time during a prior graft, after which the tree objects got garbage
collected.
Or they could be missing because of manual messing with the git-annex
branch, eg resetting it to back before the graft commit.
Sponsored-by: Dartmouth College's OpenNeuro project
Fix a bug where interrupting git-annex while it is updating the git-annex
branch could lead to git fsck complaining about missing tree objects.
Interrupting git-annex while regraftexports is running in a transition
that is forgetting git-annex branch history would leave the
repository with a git-annex branch that did not contain the tree shas
listed in export.log. That lets those trees be garbage collected.
A subsequent run of the same transition then regrafts the trees listed
in export.log into the git-annex branch. But those trees have been lost.
Note that both sides of `if neednewlocalbranch` are atomic now. I had
thought only the True side needed to be, but I do think there may be
cases where the False side needs to be as well.
Sponsored-by: Dartmouth College's OpenNeuro project
It was possible for the export.log to get written and then git-annex was
interrupted, before it could graft in the exported tree. Which could
result in export.log referencing a tree that got garbage collected.
cabal exec will sometimes output other messages to stdout, which
broke the build. It used to be intermittent in CI, now seems to always
happen. Messages are eg "Resolving dependencies..."
It seems that cabal list-bin never does this. I hope.
cabal list-bin is fairly new, needing cabal 3.8, which is only in Debian
testing/unstable. So fall back to cabal exec if it fails.
