[PATCH 3 of 5] commands: use context manager for opened bundle file

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1452835673 28800
#      Thu Jan 14 21:27:53 2016 -0800
# Node ID f550f2d4fa1553430185069d3e2954366b8ded13
# Parent  e074e8078dee56d5be493344197ea00818d51830
commands: use context manager for opened bundle file

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -2013,18 +2013,17 @@ def debugbuilddag(ui, repo, text=None,
         release(tr, lock)
 
 @command('debugbundle',
         [('a', 'all', None, _('show all details'))],
         _('FILE'),
         norepo=True)
 def debugbundle(ui, bundlepath, all=None, **opts):
     """lists the contents of a bundle"""
-    f = hg.openpath(ui, bundlepath)
-    try:
+    with hg.openpath(ui, bundlepath) as f:
         gen = exchange.readbundle(ui, f, bundlepath)
         if isinstance(gen, bundle2.unbundle20):
             return _debugbundle2(ui, gen, all=all, **opts)
         if all:
             ui.write(("format: id, p1, p2, cset, delta base, len(delta)\n"))
 
             def showchunks(named):
                 ui.write("\n%s\n" % named)
@@ -2061,18 +2060,16 @@ def debugbundle(ui, bundlepath, all=None
             chain = None
             while True:
                 chunkdata = gen.deltachunk(chain)
                 if not chunkdata:
                     break
                 node = chunkdata['node']
                 ui.write("%s\n" % hex(node))
                 chain = node
-    finally:
-        f.close()
 
 def _debugbundle2(ui, gen, **opts):
     """lists the contents of a bundle2"""
     if not isinstance(gen, bundle2.unbundle20):
         raise error.Abort(_('not a bundle2 file'))
     ui.write(('Stream params: %s\n' % repr(gen.params)))
     for part in gen.iterparts():
         ui.write('%s -- %r\n' % (part.type, repr(part.params)))