mpatch: use absolute_import

While I was here, I removed the try..except around importing cStringIO
because cStringIO should always be importable on modern Python versions.
We already do an unconditional import in other files.

mercurial/pure/mpatch.py

@@ -1,118 +1,119 b''
 # mpatch.py - Python implementation of mpatch.c
 #
 # Copyright 2009 Matt Mackall <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
+from __future__ import absolute_import
+
+import cStringIO
 import struct
-try:
-    from cStringIO import StringIO
-except ImportError:
-    from StringIO import StringIO
+
+StringIO = cStringIO.StringIO
 
 # This attempts to apply a series of patches in time proportional to
 # the total size of the patches, rather than patches * len(text). This
 # means rather than shuffling strings around, we shuffle around
 # pointers to fragments with fragment lists.
 #
 # When the fragment lists get too long, we collapse them. To do this
 # efficiently, we do all our operations inside a buffer created by
 # mmap and simply use memmove. This avoids creating a bunch of large
 # temporary string buffers.
 
 def patches(a, bins):
     if not bins:
         return a
 
     plens = [len(x) for x in bins]
     pl = sum(plens)
     bl = len(a) + pl
     tl = bl + bl + pl # enough for the patches and two working texts
     b1, b2 = 0, bl
 
     if not tl:
         return a
 
     m = StringIO()
     def move(dest, src, count):
         """move count bytes from src to dest
 
         The file pointer is left at the end of dest.
         """
         m.seek(src)
         buf = m.read(count)
         m.seek(dest)
         m.write(buf)
 
     # load our original text
     m.write(a)
     frags = [(len(a), b1)]
 
     # copy all the patches into our segment so we can memmove from them
     pos = b2 + bl
     m.seek(pos)
     for p in bins: m.write(p)
 
     def pull(dst, src, l): # pull l bytes from src
         while l:
             f = src.pop()
             if f[0] > l: # do we need to split?
                 src.append((f[0] - l, f[1] + l))
                 dst.append((l, f[1]))
                 return
             dst.append(f)
             l -= f[0]
 
     def collect(buf, list):
         start = buf
         for l, p in reversed(list):
             move(buf, p, l)
             buf += l
         return (buf - start, start)
 
     for plen in plens:
         # if our list gets too long, execute it
         if len(frags) > 128:
             b2, b1 = b1, b2
             frags = [collect(b1, frags)]
 
         new = []
         end = pos + plen
         last = 0
         while pos < end:
             m.seek(pos)
             p1, p2, l = struct.unpack(">lll", m.read(12))
             pull(new, frags, p1 - last) # what didn't change
             pull([], frags, p2 - p1)    # what got deleted
             new.append((l, pos + 12))   # what got added
             pos += l + 12
             last = p2
         frags.extend(reversed(new))     # what was left at the end
 
     t = collect(b2, frags)
 
     m.seek(t[1])
     return m.read(t[0])
 
 def patchedsize(orig, delta):
     outlen, last, bin = 0, 0, 0
     binend = len(delta)
     data = 12
 
     while data <= binend:
         decode = delta[bin:bin + 12]
         start, end, length = struct.unpack(">lll", decode)
         if start > end:
             break
         bin = data + length
         data = bin + 12
         outlen += start - last
         last = end
         outlen += length
 
     if bin != binend:
         raise ValueError("patch cannot be decoded")
 
     outlen += orig - last
     return outlen

tests/test-check-py3-compat.t

@@ -1,216 +1,215 b''
 #require test-repo
 
   $ cd "$TESTDIR"/..
 
   $ hg files 'set:(**.py)' | xargs python contrib/check-py3-compat.py
   contrib/casesmash.py not using absolute_import
   contrib/check-code.py not using absolute_import
   contrib/check-code.py requires print_function
   contrib/check-config.py not using absolute_import
   contrib/check-config.py requires print_function
   contrib/debugcmdserver.py not using absolute_import
   contrib/debugcmdserver.py requires print_function
   contrib/debugshell.py not using absolute_import
   contrib/fixpax.py not using absolute_import
   contrib/fixpax.py requires print_function
   contrib/hgclient.py not using absolute_import
   contrib/hgclient.py requires print_function
   contrib/hgfixes/fix_bytes.py not using absolute_import
   contrib/hgfixes/fix_bytesmod.py not using absolute_import
   contrib/hgfixes/fix_leftover_imports.py not using absolute_import
   contrib/import-checker.py not using absolute_import
   contrib/import-checker.py requires print_function
   contrib/memory.py not using absolute_import
   contrib/perf.py not using absolute_import
   contrib/python-hook-examples.py not using absolute_import
   contrib/revsetbenchmarks.py not using absolute_import
   contrib/revsetbenchmarks.py requires print_function
   contrib/showstack.py not using absolute_import
   contrib/synthrepo.py not using absolute_import
   contrib/win32/hgwebdir_wsgi.py not using absolute_import
   doc/check-seclevel.py not using absolute_import
   doc/gendoc.py not using absolute_import
   doc/hgmanpage.py not using absolute_import
   hgext/__init__.py not using absolute_import
   hgext/acl.py not using absolute_import
   hgext/blackbox.py not using absolute_import
   hgext/bugzilla.py not using absolute_import
   hgext/censor.py not using absolute_import
   hgext/children.py not using absolute_import
   hgext/churn.py not using absolute_import
   hgext/clonebundles.py not using absolute_import
   hgext/color.py not using absolute_import
   hgext/convert/__init__.py not using absolute_import
   hgext/convert/bzr.py not using absolute_import
   hgext/convert/common.py not using absolute_import
   hgext/convert/convcmd.py not using absolute_import
   hgext/convert/cvs.py not using absolute_import
   hgext/convert/cvsps.py not using absolute_import
   hgext/convert/darcs.py not using absolute_import
   hgext/convert/filemap.py not using absolute_import
   hgext/convert/git.py not using absolute_import
   hgext/convert/gnuarch.py not using absolute_import
   hgext/convert/hg.py not using absolute_import
   hgext/convert/monotone.py not using absolute_import
   hgext/convert/p4.py not using absolute_import
   hgext/convert/subversion.py not using absolute_import
   hgext/convert/transport.py not using absolute_import
   hgext/eol.py not using absolute_import
   hgext/extdiff.py not using absolute_import
   hgext/factotum.py not using absolute_import
   hgext/fetch.py not using absolute_import
   hgext/gpg.py not using absolute_import
   hgext/graphlog.py not using absolute_import
   hgext/hgcia.py not using absolute_import
   hgext/hgk.py not using absolute_import
   hgext/highlight/__init__.py not using absolute_import
   hgext/highlight/highlight.py not using absolute_import
   hgext/histedit.py not using absolute_import
   hgext/keyword.py not using absolute_import
   hgext/largefiles/__init__.py not using absolute_import
   hgext/largefiles/basestore.py not using absolute_import
   hgext/largefiles/lfcommands.py not using absolute_import
   hgext/largefiles/lfutil.py not using absolute_import
   hgext/largefiles/localstore.py not using absolute_import
   hgext/largefiles/overrides.py not using absolute_import
   hgext/largefiles/proto.py not using absolute_import
   hgext/largefiles/remotestore.py not using absolute_import
   hgext/largefiles/reposetup.py not using absolute_import
   hgext/largefiles/uisetup.py not using absolute_import
   hgext/largefiles/wirestore.py not using absolute_import
   hgext/mq.py not using absolute_import
   hgext/notify.py not using absolute_import
   hgext/pager.py not using absolute_import
   hgext/patchbomb.py not using absolute_import
   hgext/purge.py not using absolute_import
   hgext/rebase.py not using absolute_import
   hgext/record.py not using absolute_import
   hgext/relink.py not using absolute_import
   hgext/schemes.py not using absolute_import
   hgext/share.py not using absolute_import
   hgext/shelve.py not using absolute_import
   hgext/strip.py not using absolute_import
   hgext/transplant.py not using absolute_import
   hgext/win32mbcs.py not using absolute_import
   hgext/win32text.py not using absolute_import
   hgext/zeroconf/Zeroconf.py not using absolute_import
   hgext/zeroconf/Zeroconf.py requires print_function
   hgext/zeroconf/__init__.py not using absolute_import
   i18n/check-translation.py not using absolute_import
   i18n/polib.py not using absolute_import
   mercurial/byterange.py not using absolute_import
   mercurial/cmdutil.py not using absolute_import
   mercurial/commands.py not using absolute_import
   mercurial/commandserver.py not using absolute_import
   mercurial/context.py not using absolute_import
   mercurial/dirstate.py not using absolute_import
   mercurial/dispatch.py requires print_function
   mercurial/encoding.py not using absolute_import
   mercurial/exchange.py not using absolute_import
   mercurial/help.py not using absolute_import
   mercurial/httpclient/__init__.py not using absolute_import
   mercurial/httpclient/_readers.py not using absolute_import
   mercurial/httpclient/socketutil.py not using absolute_import
   mercurial/httpconnection.py not using absolute_import
   mercurial/keepalive.py not using absolute_import
   mercurial/keepalive.py requires print_function
   mercurial/localrepo.py not using absolute_import
   mercurial/lsprof.py requires print_function
   mercurial/lsprofcalltree.py not using absolute_import
   mercurial/lsprofcalltree.py requires print_function
   mercurial/mail.py requires print_function
   mercurial/manifest.py not using absolute_import
   mercurial/mdiff.py not using absolute_import
   mercurial/patch.py not using absolute_import
-  mercurial/pure/mpatch.py not using absolute_import
   mercurial/pure/osutil.py not using absolute_import
   mercurial/pure/parsers.py not using absolute_import
   mercurial/pvec.py not using absolute_import
   mercurial/py3kcompat.py not using absolute_import
   mercurial/revlog.py not using absolute_import
   mercurial/scmposix.py not using absolute_import
   mercurial/scmutil.py not using absolute_import
   mercurial/scmwindows.py not using absolute_import
   mercurial/similar.py not using absolute_import
   mercurial/store.py not using absolute_import
   mercurial/util.py not using absolute_import
   mercurial/windows.py not using absolute_import
   setup.py not using absolute_import
   tests/filterpyflakes.py requires print_function
   tests/generate-working-copy-states.py requires print_function
   tests/get-with-headers.py requires print_function
   tests/heredoctest.py requires print_function
   tests/hypothesishelpers.py not using absolute_import
   tests/hypothesishelpers.py requires print_function
   tests/killdaemons.py not using absolute_import
   tests/md5sum.py not using absolute_import
   tests/mockblackbox.py not using absolute_import
   tests/printenv.py not using absolute_import
   tests/readlink.py not using absolute_import
   tests/readlink.py requires print_function
   tests/revlog-formatv0.py not using absolute_import
   tests/run-tests.py not using absolute_import
   tests/seq.py not using absolute_import
   tests/seq.py requires print_function
   tests/silenttestrunner.py not using absolute_import
   tests/silenttestrunner.py requires print_function
   tests/sitecustomize.py not using absolute_import
   tests/svn-safe-append.py not using absolute_import
   tests/svnxml.py not using absolute_import
   tests/test-ancestor.py requires print_function
   tests/test-atomictempfile.py not using absolute_import
   tests/test-batching.py not using absolute_import
   tests/test-batching.py requires print_function
   tests/test-bdiff.py not using absolute_import
   tests/test-bdiff.py requires print_function
   tests/test-context.py not using absolute_import
   tests/test-context.py requires print_function
   tests/test-demandimport.py not using absolute_import
   tests/test-demandimport.py requires print_function
   tests/test-dispatch.py not using absolute_import
   tests/test-dispatch.py requires print_function
   tests/test-doctest.py not using absolute_import
   tests/test-duplicateoptions.py not using absolute_import
   tests/test-duplicateoptions.py requires print_function
   tests/test-filecache.py not using absolute_import
   tests/test-filecache.py requires print_function
   tests/test-filelog.py not using absolute_import
   tests/test-filelog.py requires print_function
   tests/test-hg-parseurl.py not using absolute_import
   tests/test-hg-parseurl.py requires print_function
   tests/test-hgweb-auth.py not using absolute_import
   tests/test-hgweb-auth.py requires print_function
   tests/test-hgwebdir-paths.py not using absolute_import
   tests/test-hybridencode.py not using absolute_import
   tests/test-hybridencode.py requires print_function
   tests/test-lrucachedict.py not using absolute_import
   tests/test-lrucachedict.py requires print_function
   tests/test-manifest.py not using absolute_import
   tests/test-minirst.py not using absolute_import
   tests/test-minirst.py requires print_function
   tests/test-parseindex2.py not using absolute_import
   tests/test-parseindex2.py requires print_function
   tests/test-pathencode.py not using absolute_import
   tests/test-pathencode.py requires print_function
   tests/test-propertycache.py not using absolute_import
   tests/test-propertycache.py requires print_function
   tests/test-revlog-ancestry.py not using absolute_import
   tests/test-revlog-ancestry.py requires print_function
   tests/test-run-tests.py not using absolute_import
   tests/test-simplemerge.py not using absolute_import
   tests/test-status-inprocess.py not using absolute_import
   tests/test-status-inprocess.py requires print_function
   tests/test-symlink-os-yes-fs-no.py not using absolute_import
   tests/test-trusted.py not using absolute_import
   tests/test-trusted.py requires print_function
   tests/test-ui-color.py not using absolute_import
   tests/test-ui-color.py requires print_function
   tests/test-ui-config.py not using absolute_import
   tests/test-ui-config.py requires print_function
   tests/test-ui-verbosity.py not using absolute_import
   tests/test-ui-verbosity.py requires print_function
   tests/test-url.py not using absolute_import
   tests/test-url.py requires print_function
   tests/test-walkrepo.py requires print_function
   tests/test-wireproto.py requires print_function
   tests/tinyproxy.py requires print_function