tests/test-changelog-exec.t

wix: tell ComponentSearch that it is finding a directory (not a file)

This is to fix an issue we've noticed where fresh installations start at
`C:\Program Files\Mercurial`, and then upgrades "walk up" the tree and end up in
`C:\Program Files` and finally `C:\` (where they stay).

ComponentSearch defaults to finding files, which I think means "it produces a
string like `C:\Program Files\Mercurial`", whereas with the type being
explicitly a directory, it would return `C:\Program Files\Mercurial\` (note the
final trailing backslash). Presumably, a latter step then tries to turn that
file name into a proper directory, by removing everything after the last `\`.

This could likely also be fixed by actually searching for the component for
hg.exe itself. That seemed a lot more complicated, as the GUID for hg.exe isn't
known in this file (it's one of the "auto-derived" ones). We could also consider
adding a Condition that I think could check the Property and ensure it's either
empty or ends in a trailing slash, but that would be an installer runtime check
and I'm not convinced it'd actually be useful.

This will *not* cause existing installations that are in one of the bad
directories to fix themselves. Doing that would require a fair amount more
understanding of wix and windows installer than I have, and it *probably*
wouldn't be possible to be 100% correct about it either (there's nothing
preventing a user from intentionally installing it in C:\, though I don't know
why they would do so).

If someone wants to tackle fixing existing installations, I think that the first
installation is actually the only one that shows up in "Add or Remove Programs",
and that its registry keys still exist. You might be able to find something
under HKEY_USERS that lists both the "good" and the "bad" InstallDirs. Mine was
under `HKEY_USERS\S-1-5-18\Software\Mercurial\InstallDir` (C:\), and
`HKEY_USERS\S-1-5-21-..numbers..\Software\Mercurial\InstallDir` (C:\Program
Files\Mercurial). If you find exactly two, with one being the default path, and
the other being a prefix of it, the user almost certainly hit this bug :D

We had originally thought that this bug might be due to unattended
installations/upgrades, but I no longer think that's the case. We were able to
reproduce the issue by uninstalling all copies of Mercurial I could find,
installing one version (it chose the correct location), and then starting the
installer for a different version (higher or lower didn't matter). I did not
need to deal with an unattended or headless installation/upgrade to trigger the
issue, but it's possible that my system was "primed" for this bug to happen
because of a previous unattended installation/upgrade.

Differential Revision: https://phab.mercurial-scm.org/D9891

#require execbit

b51a8138292a introduced a regression where we would mention in the
changelog executable files added by the second parent of a merge. Test
that that doesn't happen anymore

  $ hg init repo
  $ cd repo
  $ echo foo > foo
  $ hg ci -qAm 'add foo'

  $ echo bar > bar
  $ chmod +x bar
  $ hg ci -qAm 'add bar'

manifest of p2:

  $ hg manifest
  bar
  foo

  $ hg up -qC 0
  $ echo >> foo
  $ hg ci -m 'change foo'
  created new head

manifest of p1:

  $ hg manifest
  foo

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ chmod +x foo
  $ hg ci -m 'merge'

this should not mention bar but should mention foo:

  $ hg tip -v
  changeset:   3:c53d17ff3380
  tag:         tip
  parent:      2:ed1b79f46b9a
  parent:      1:d394a8db219b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       foo
  description:
  merge
  
  

  $ hg debugindex bar
     rev linkrev nodeid       p1           p2
       0       1 b004912a8510 000000000000 000000000000

  $ cd ..