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.

branching: merge stable into default

relnotes: add 6.2.1 and 6.2.2

Added signature for changeset b5c8524827d2

Added tag 6.2.2 for changeset b5c8524827d2

dirstate-v2: no longer register the data-file during transaction If the data file change during the transaction, we cannot truncate it. The content of the file itself is fine as it will get backed up at the same time as the docket. Leaving the trailing data at the end of failed transaction is fine. The dirstate-v2 format supports it. The dead data will simply we written over if necessary.

fsmonitor: use new dirstate APIs (issue6728) On top of fixing fsmonitor, it moves one more "old API" use to the new one. This needs very verbose code to save a few function calls that are very expensive in Python.

dirstate-v2: backup the data file during the transaction (issue6730) If we backup of the docket, without doing a backup of the data file, we highly risk restoring a docket pointing to a missing file in the future. So we now backup the data-file alongside the docket.