revlog: finer computation of "issnapshot"
If the parent had an empty diff, we skip of it to compute a diff against the
parent base. This create shorter and simpler chain.
However these case could be wrongly detected as snapshot. So we improve the code
doing this detection.
In practice nobody care as when tried on a copy of mozilla-try and we got the
same number of snapshot (1315) in both case.
Performance where equivalent.
perf: make perf::bundle compatible down to 5.2
A another small change to make it compatible with a wider set of revision.
I did not check compatibility in the python-2 territory yet.
perf: make perf::bundle compatible before
61ba04693d65
A small change to make it compatible with a wider set of revision.
Added signature for changeset
b5c8524827d2