> And > certainly we _have_ seen real-world cases, such as the one fixed by > 806278dead (commit-graph.c: handle corrupt/missing trees, 2019-09-05). > > Note that we can't quite drop the check in the caller added by that > commit yet, as there's some subtlety with repeated parsings (which will > be addressed in a future commit). I tried figuring out what the subtlety is by undoing the check you describe, and did get a segfault in one of the tests, but couldn't figure out exactly what is going on. Looking at the code, is it because load_tree_for_commit() in commit-graph.c uses the return value of lookup_tree() indiscriminately (which is the issue that this patch fixes)? This patch itself and patch 1 looks good (with the reasoning in the commit message), of course.
