tests/test-pathconflicts-basic.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

Path conflict checking is currently disabled by default because of issue5716.
Turn it on for this test.

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > merge.checkpathconflicts=True
  > EOF

  $ hg init repo
  $ cd repo
  $ echo base > base
  $ hg add base
  $ hg commit -m "base"
  $ hg bookmark -i base
  $ echo 1 > a
  $ hg add a
  $ hg commit -m "file"
  $ hg bookmark -i file
  $ echo 2 > a
  $ hg commit -m "file2"
  $ hg bookmark -i file2
  $ hg up -q 0
  $ mkdir a
  $ echo 2 > a/b
  $ hg add a/b
  $ hg commit -m "dir"
  created new head
  $ hg bookmark -i dir

Basic merge - local file conflicts with remote directory

  $ hg up -q file
  $ hg bookmark -i
  $ hg merge --verbose dir
  resolving manifests
  a: path conflict - a file or link has the same name as a directory
  the local file has been renamed to a~853701544ac3
  resolve manually then use 'hg resolve --mark a'
  moving a to a~853701544ac3
  getting a/b
  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]
  $ hg update --clean .
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ rm a~853701544ac3

Basic update - local directory conflicts with remote file

  $ hg up -q 0
  $ mkdir a
  $ echo 3 > a/b
  $ hg up file
  a: untracked directory conflicts with file
  abort: untracked files in working directory differ from files in requested revision
  [255]
  $ hg up --clean file
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark file)

Repo state is ok

  $ hg sum
  parent: 1:853701544ac3 
   file
  branch: default
  bookmarks: *file
  commit: (clean)
  update: 2 new changesets (update)
  phases: 4 draft

Basic update - untracked file conflicts with remote directory

  $ hg up -q 0
  $ echo untracked > a
  $ hg up --config merge.checkunknown=warn dir
  a: replacing untracked file
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark dir)
  $ cat a.orig
  untracked
  $ rm -f a.orig

Basic clean update - local directory conflicts with changed remote file

  $ hg up -q file
  $ rm a
  $ mkdir a
  $ echo 4 > a/b
  $ hg up file2
  abort: *: *$TESTTMP/repo/a* (glob)
  [255]
  $ hg up --clean file2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark file2)

Repo state is ok

  $ hg sum
  parent: 2:f64e09fac717 
   file2
  branch: default
  bookmarks: *file2
  commit: (clean)
  update: 1 new changesets, 2 branch heads (merge)
  phases: 4 draft