tests/test-mac-packages.t

repair: move check for existing transaction earlier

Several benefits:

 * Gets close the comment describing it
 * Splits off unrelated comment about "backup" argument
 * Error checking is customarily done early
 * If we added an early return to the method, it would still
   consistently fail if there was an existing transaction (so
   we would find and fix that case quickly)

One test needs updating with for this change, because we no longer
create the backup bundle before we fail. I don't see much reason to
create that backup bundle. If some command was adding content and then
trying to strip it as well within the transaction, we would have a
backup for the user, but the risk of that not being discovered in
development seems very small.

#require test-repo slow osx osxpackaging

  $ . "$TESTDIR/helpers-testrepo.sh"

  $ OUTPUTDIR="`pwd`"
  $ export OUTPUTDIR
  $ KEEPMPKG=yes
  $ export KEEPMPKG

  $ cd "$TESTDIR"/..
  $ make osx > "$OUTPUTDIR/build.log" 2>&1
  $ cd "$OUTPUTDIR"
  $ ls -d *.pkg
  Mercurial-*-macosx10.*.pkg (glob)

  $ xar -xf Mercurial*.pkg

Gather list of all installed files:
  $ lsbom mercurial.pkg/Bom > boms.txt

We've had problems with the filter logic in the past. Make sure no
.DS_Store files ended up in the final package:
  $ grep DS_S boms.txt
  [1]

Spot-check some randomly selected files:
  $ grep bdiff boms.txt | cut -d '	' -f 1,2,3
  ./Library/Python/2.7/site-packages/mercurial/cext/bdiff.so	100755	0/0
  ./Library/Python/2.7/site-packages/mercurial/pure/bdiff.py	100644	0/0
  ./Library/Python/2.7/site-packages/mercurial/pure/bdiff.pyc	100644	0/0
  ./Library/Python/2.7/site-packages/mercurial/pure/bdiff.pyo	100644	0/0
  $ grep zsh/site-functions/_hg boms.txt | cut -d '	' -f 1,2,3
  ./usr/local/share/zsh/site-functions/_hg	100644	0/0
  $ grep hg-completion.bash boms.txt | cut -d '	' -f 1,2,3
  ./usr/local/hg/contrib/hg-completion.bash	100644	0/0
  $ egrep 'man[15]' boms.txt | cut -d '	' -f 1,2,3
  ./usr/local/share/man/man1	40755	0/0
  ./usr/local/share/man/man1/chg.1	100644	0/0
  ./usr/local/share/man/man1/hg.1	100644	0/0
  ./usr/local/share/man/man5	40755	0/0
  ./usr/local/share/man/man5/hgignore.5	100644	0/0
  ./usr/local/share/man/man5/hgrc.5	100644	0/0
  $ grep bser boms.txt | cut -d '	' -f 1,2,3
  ./Library/Python/2.7/site-packages/hgext/fsmonitor/pywatchman/bser.so	100755	0/0
  ./Library/Python/2.7/site-packages/hgext/fsmonitor/pywatchman/pybser.py	100644	0/0
  ./Library/Python/2.7/site-packages/hgext/fsmonitor/pywatchman/pybser.pyc	100644	0/0
  ./Library/Python/2.7/site-packages/hgext/fsmonitor/pywatchman/pybser.pyo	100644	0/0
  $ grep localrepo boms.txt | cut -d '	' -f 1,2,3
  ./Library/Python/2.7/site-packages/mercurial/localrepo.py	100644	0/0
  ./Library/Python/2.7/site-packages/mercurial/localrepo.pyc	100644	0/0
  ./Library/Python/2.7/site-packages/mercurial/localrepo.pyo	100644	0/0
  $ egrep 'bin/' boms.txt | cut -d '	' -f 1,2,3
  ./usr/local/bin/chg	100755	0/0
  ./usr/local/bin/hg	100755	0/0

Make sure the built binary uses the system Python interpreter
  $ bsdtar xf mercurial.pkg/Payload usr/local/bin
Use a glob to find this to avoid check-code whining about a fixed path.
  $ head -n 1 usr/local/b?n/hg
  #!/System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python

Note that we're not currently installing any /etc/mercurial stuff,
including merge-tool configurations.