tests/autodiff.py

repair: use context manager for lock management

If repo.lock() raised inside of the try block, 'tr' would have been None in the
finally block where it tries to release().  Modernize the syntax instead of just
winching the lock out of the try block.

I found several other instances of acquiring the lock inside of the 'try', but
those finally blocks handle None references.  I also started switching some
trivial try/finally blocks to context managers, but didn't get them all because
indenting over 3x for lock, wlock and transaction would have spilled over 80
characters.  That got me wondering if there should be a repo.rwlock(), to handle
locking and unlocking in the proper order.

It also looks like py27 supports supports multiple context managers for a single
'with' statement.  Should I hold off on the rest until py26 is dropped?

# Extension dedicated to test patch.diff() upgrade modes

from __future__ import absolute_import

from mercurial import (
    cmdutil,
    error,
    patch,
    scmutil,
)

cmdtable = {}
command = cmdutil.command(cmdtable)

@command('autodiff',
    [('', 'git', '', 'git upgrade mode (yes/no/auto/warn/abort)')],
    '[OPTION]... [FILE]...')
def autodiff(ui, repo, *pats, **opts):
    diffopts = patch.difffeatureopts(ui, opts)
    git = opts.get('git', 'no')
    brokenfiles = set()
    losedatafn = None
    if git in ('yes', 'no'):
        diffopts.git = git == 'yes'
        diffopts.upgrade = False
    elif git == 'auto':
        diffopts.git = False
        diffopts.upgrade = True
    elif git == 'warn':
        diffopts.git = False
        diffopts.upgrade = True
        def losedatafn(fn=None, **kwargs):
            brokenfiles.add(fn)
            return True
    elif git == 'abort':
        diffopts.git = False
        diffopts.upgrade = True
        def losedatafn(fn=None, **kwargs):
            raise error.Abort('losing data for %s' % fn)
    else:
        raise error.Abort('--git must be yes, no or auto')

    node1, node2 = scmutil.revpair(repo, [])
    m = scmutil.match(repo[node2], pats, opts)
    it = patch.diff(repo, node1, node2, match=m, opts=diffopts,
                    losedatafn=losedatafn)
    for chunk in it:
        ui.write(chunk)
    for fn in sorted(brokenfiles):
        ui.write(('data lost for: %s\n' % fn))