scmutil: use context managers for file handles
Now that we dropped support for Python 2.4, we are able to use context
managers. Let's replace the try..finally pattern in scmutil.py with
context managers, which close files automatically when the context
manager is exited.
There should be no change in behavior with this patch.
Why convert to context managers if nothing is broken? I'm working on
closing file handles in background threads to improve performance on
Windows. As part of this, I realized there could be some future issues
if the background file closing code isn't designed with context
managers in mind. So, I'd like to switch some code to context managers
so I can design an API that works with context managers.
syntax: glob
*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
tests/.coverage*
tests/.testtimes*
tests/annotated
tests/*.err
tests/htmlcov
build
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.idea/*
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py
# files installed with a local --pure build
mercurial/base85.py
mercurial/bdiff.py
mercurial/diffhelpers.py
mercurial/mpatch.py
mercurial/osutil.py
mercurial/parsers.py
syntax: regexp
^\.pc/
^\.(pydev)?project
# hackable windows distribution additions
^hg-python
^hg.py$