branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
Testing recorded "modified" files for merge commit
==================================================
This file shows what hg says are "modified" files for a merge commit
(hg log -T {files}), somewhat exhaustively.
This file test multiple corner case.
For merges that involve files contents changing, check test-merge-combination-file-content.t
For merges that involve executable bit changing, check test-merge-combination-exec-bytes.t
Case with multiple or zero merge ancestors, copies/renames, and identical file contents
with different filelog revisions are not currently covered.
$ . $TESTDIR/testlib/merge-combination-util.sh
Files modified or cleanly merged, with no greatest common ancestors:
$ hg init repo; cd repo
$ touch a0 b0; hg commit -qAm 0
$ hg up -qr null; touch a1 b1; hg commit -qAm 1
$ hg merge -qr 0; rm b*; hg commit -qAm 2
$ hg log -r . -T '{files}\n'
b0 b1
$ cd ../
$ rm -rf repo
A few cases of criss-cross merges involving deletions (listing all
such merges is probably too much). Both gcas contain $files, so we
expect the final merge to behave like a merge with a single gca
containing $files.
$ hg init repo; cd repo
$ files="c1 u1 c2 u2"
$ touch $files; hg commit -qAm '0 root'
$ for f in $files; do echo f > $f; done; hg commit -qAm '1 gca1'
$ hg up -qr0; hg revert -qr 1 --all; hg commit -qAm '2 gca2'
$ hg up -qr 1; hg merge -qr 2; rm *1; hg commit -qAm '3 p1'
$ hg up -qr 2; hg merge -qr 1; rm *2; hg commit -qAm '4 p2'
$ hg merge -qr 3; echo f > u1; echo f > u2; rm -f c1 c2
$ hg commit -qAm '5 merge with two gcas'
$ hg log -r . -T '{files}\n' # expecting u1 u2
$ cd ../
$ rm -rf repo