view tests/test-issue2137.t @ 21857:86c2d792a4b7

util: replace 'ellipsis' implementation by 'encoding.trim'

Before this patch, 'util.ellipsis' tried to avoid splitting at
intermediate multi-byte sequence, but its implementation was incorrect.

Internal function '_ellipsis' trims specified unicode sequence not at
most maxlength 'columns in display', but at most maxlength number of
'unicode characters'.

    def _ellipsis(text, maxlength):
        if len(text) <= maxlength:
            return text, False
        else:
            return "%s..." % (text[:maxlength - 3]), True

In many encodings, number of unicode characters can be different from
columns in display.

This patch replaces 'ellipsis' implementation by 'encoding.trim',
which can trim string at most maxlength columns in display correctly,
even though specified string contains multi-byte characters.

'_ellipsis' is removed in this patch, because it is referred only from
'ellipsis'.

http://mercurial.selenic.com/bts/issue2137

Setup:

create a little extension that has 3 side-effects:
1) ensure changelog data is not inlined
2) make revlog to use lazyparser
3) test that repo.lookup() works
1 and 2 are preconditions for the bug; 3 is the bug.

  $ cat > commitwrapper.py <<EOF
  > from mercurial import extensions, node, revlog
  > 
  > def reposetup(ui, repo):
  >     class wraprepo(repo.__class__):
  >         def commit(self, *args, **kwargs):
  >             result = super(wraprepo, self).commit(*args, **kwargs)
  >             tip1 = node.short(repo.changelog.tip())
  >             tip2 = node.short(repo.lookup(tip1))
  >             assert tip1 == tip2
  >             ui.write('new tip: %s\n' % tip1)
  >             return result
  >     repo.__class__ = wraprepo
  > 
  > def extsetup(ui):
  >     revlog._maxinline = 8             # split out 00changelog.d early
  >     revlog._prereadsize = 8           # use revlog.lazyparser
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > commitwrapper = `pwd`/commitwrapper.py
  > EOF

  $ hg init repo1
  $ cd repo1
  $ echo a > a
  $ hg commit -A -m'add a with a long commit message to make the changelog a bit bigger'
  adding a
  new tip: 553596fad57b

Test that new changesets are visible to repo.lookup():

  $ echo a >> a
  $ hg commit -m'one more commit to demonstrate the bug'
  new tip: 799ae3599e0e

  $ hg tip
  changeset:   1:799ae3599e0e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     one more commit to demonstrate the bug
  

  $ cd ..