largefiles: show hashes before prompting for conflict resolution
The largefile hashes are mostly an implementation detail, but they are "leaked"
in several places anyway, and showing the hashes is better than not giving the
user any information about the options in the prompt.
The hashes are long, but it is largefile hashes and it would thus be confusing
to shorten them.
largefiles: don't try to explain rename history before prompt for conflicts
Before it tried to explain the exact situation when merging moved largefiles.
That do not happen for normal merges and is not more relevant for largefiles
than for normal files. It is unneeded complexity - remove it.
largefiles: drop redundant special handling of merges of renames
It is unclear what cases this was supposed to cover but it do no longer seem
relevant.
diff: search beyond ancestor when detecting renames
This removes an optimization that was introduced in
91eb4512edd0 but was too
aggressive - as indicated by how it changed test-mq-merge.t .
We are walking filelogs to find copy sources and we can thus not be sure to hit
the base revision and find the renamed file there - it could also be in the
first ancestor of the base ... in the filelog.
We are walking the filelog and can thus not easily know when we hit the first
ancestor of the base revision and which filename to look for there. Instead, we
use _findlimit like mergecopies do: The lower bound for how far we have to go
is found from the lowest changelog revision that is an ancestor of only one of
the compared revisions. Any filelog ancestor with a revision number lower than
that revision will be the ancestor of both compared revisions, and there is
thus no reason to go further back than that.
cat: increase perf when catting single files
Special case the single file case in hg cat. This allows us to avoid
parsing the manifest, which shaves 15% off hg cat perf. This is worth
it, since automation often uses hg cat for retrieving single files.