view tests/test-relink.t @ 17103:5146de7bce96

convert: keep branch switching merges with ancestors (issue3340)

When running convert with a filemap, merge parents which are ancestors
of other parents are ignored. This is hardly a problem when parents
belong to the same branch, but the result could be confusing when named
branches are involved. With:

  -o-a1-a2-a3...     <- A
    \           \
     b1-b2-b3...-m-  <- B

If all b* revisions are discarded, it is useful to preserve 'm' even if
it is empty after filtering to record the branch switch.

This patch makes filemap preserve "ancestor parents" if there is no
"non-ancestor parent" on the same branch than the merge revision.

Remarks:
- I am not completely convinced by the reasons given above and those
  detailed by Matt in this thread:

http://selenic.com/pipermail/mercurial-devel/2012-May/040627.html

  The properties we try to preserve are not clearly defined. That said,
  I know this patch already helped someone on IRC and the tests output
  look reasonable.

- This is a new version of the original "convert: filemap must preserve
  fast-forward merges" patch. It has exactly the same output for 2
  parents merges, the additional complexity is here to handle more than
  two parents.

  $ "$TESTDIR/hghave" hardlink || exit 80

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "relink=" >> $HGRCPATH

  $ fix_path() {
  >     tr '\\' /
  > }

  $ cat > arelinked.py <<EOF
  > import sys, os
  > from mercurial import util
  > path1, path2 = sys.argv[1:3]
  > if util.samefile(path1, path2):
  >     print '%s == %s' % (path1, path2)
  > else:
  >     print '%s != %s' % (path1, path2)
  > EOF


create source repository

  $ hg init repo
  $ cd repo
  $ echo a > a
  $ echo b > b
  $ hg ci -Am addfile
  adding a
  adding b
  $ cat "$TESTDIR/binfile.bin" >> a
  $ cat "$TESTDIR/binfile.bin" >> b
  $ hg ci -Am changefiles

make another commit to create files larger than 1 KB to test
formatting of final byte count

  $ cat "$TESTDIR/binfile.bin" >> a
  $ cat "$TESTDIR/binfile.bin" >> b
  $ hg ci -m anotherchange

don't sit forever trying to double-lock the source repo

  $ hg relink .
  relinking $TESTTMP/repo/.hg/store to $TESTTMP/repo/.hg/store (glob)
  there is nothing to relink


Test files are read in binary mode

  $ python -c "file('.hg/store/data/dummy.i', 'wb').write('a\r\nb\n')"
  $ cd ..


clone and pull to break links

  $ hg clone --pull -r0 repo clone
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd clone
  $ hg pull -q
  $ echo b >> b
  $ hg ci -m changeb
  created new head
  $ python -c "file('.hg/store/data/dummy.i', 'wb').write('a\nb\r\n')"


relink

  $ hg relink --debug | fix_path
  relinking $TESTTMP/repo/.hg/store to $TESTTMP/clone/.hg/store
  tip has 2 files, estimated total number of files: 3
  collecting: 00changelog.i 1/3 files (33.33%)
  collecting: 00manifest.i 2/3 files (66.67%)
  collecting: a.i 3/3 files (100.00%)
  collecting: b.i 4/3 files (133.33%)
  collecting: dummy.i 5/3 files (166.67%)
  collected 5 candidate storage files
  not linkable: 00changelog.i
  not linkable: 00manifest.i
  pruning: data/a.i 3/5 files (60.00%)
  not linkable: data/b.i
  pruning: data/dummy.i 5/5 files (100.00%)
  pruned down to 2 probably relinkable files
  relinking: data/a.i 1/2 files (50.00%)
  not linkable: data/dummy.i
  relinked 1 files (1.37 KB reclaimed)
  $ cd ..


check hardlinks

  $ python arelinked.py repo/.hg/store/data/a.i clone/.hg/store/data/a.i
  repo/.hg/store/data/a.i == clone/.hg/store/data/a.i
  $ python arelinked.py repo/.hg/store/data/b.i clone/.hg/store/data/b.i
  repo/.hg/store/data/b.i != clone/.hg/store/data/b.i