log: fix --follow null parent not to include revision 0
If p1 is null, ':.' is translated as '0:null'. But rangeset can't handle null,
only revision 0 was visible. Because 'null' should not be listed implicitly,
"log --follow" (without -r) should be empty if p1 is null.
Test of "hg grep -f" is added for cmdutil.walkchangerevs().
graphlog: remove useless check for empty repo when --follow is specified
This prepares for extracting common part from getgraphlogrevs() and
getlogrevs(). getlogrevs() does not handle empty repo specially.
When it was added at
d74099ac2ac1, revs were build by old-style query, '.:0'.
So I think the purpose of "len(repo) > 0" was to handle the case of . = null.
Currently it isn't necessary for 'reverse(:.)', and it does not work if repo
is not empty but p1 is null.
$ hg up null
$ hg glog --follow -T '{rev}:{node|short}\n'
o 0:
0a04b987be5a
The subsequent patch will fix this problem, so drops the wrong version for now.
graphlog: move comment and flag denoting revs might be unsorted
This prepares for extracting common part from getgraphlogrevs() and
getlogrevs(). "possiblyunsorted" exists only in getgraphlogrevs().
graphlog: remove too early return from getgraphlogrevs() for empty repo
Even if repository is empty, null revision should exist.
trydiff: call util.binary in only one place
It's practically free to call util.binary on empty or None content. By
relying on that, we can replace the current four call sites by one.
trydiff: collect all lossiness checks in one place
By having all the checks for lossiness in one place, it becomes much
easier to get an overview of the conditions that lead to losedatafn()
being called. It also makes it obvious that it can not be called
multiple times for a single time (something that was rather tricky to
determine before).