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.
#require docutils gettext
Error: the current ro localization has some rst defects exposed by
moving pager to core. These two warnings about references are expected
until the localization is corrected.
$ $TESTDIR/check-gendoc ro
checking for parse errors
gendoc.txt:58: (WARNING/2) Inline interpreted text or phrase reference start-string without end-string.
gendoc.txt:58: (WARNING/2) Inline interpreted text or phrase reference start-string without end-string.