Stefan Beller <sbeller@xxxxxxxxxx> writes: > $ git hash-object --stdin -w -t commit <<EOF > tree c70b4a33a0089f15eb3b38092832388d75293e86 > parent 105d5b91138ced892765a84e771a061ede8d63b8 > author Stefan Beller <sbeller@xxxxxxxxxx> 1519859216 -0800 > committer Stefan Beller <sbeller@xxxxxxxxxx> 1519859216 -0800 > tree 5495266479afc9a4bd9560e9feac465ed43fa63a > test commit > EOF > 19abfc3bf1c5d782045acf23abdf7eed81e16669 > $ git fsck |grep 19abfc3bf1c5d782045acf23abdf7eed81e16669 > $ > > So it is technically possible to create a commit with two tree entries > and fsck is not complaining. The second one is merely a random unauthorized header that is not interpreted in any way by Git. It is merely being confusing by starting with "tree " and having 40-hex after it, but the 40-hex does not get interpreted as an object name, and does not participate in reachability computation (i.e. packing, pruning and fsck). There is not much difference between that and a line of trailer in the commit log message (other than this one is less discoverable).
