tests: fix printenv script on Python 3

Differential Revision: https://phab.mercurial-scm.org/D3725

tests/printenv.py

@@ -1,53 +1,54 b''
 #!/usr/bin/env python
 #
 # simple script to be used in hooks
 #
 # put something like this in the repo .hg/hgrc:
 #
 #     [hooks]
 #     changegroup = python "$TESTDIR/printenv.py" <hookname> [exit] [output]
 #
 #   - <hookname> is a mandatory argument (e.g. "changegroup")
 #   - [exit] is the exit code of the hook (default: 0)
 #   - [output] is the name of the output file (default: use sys.stdout)
 #              the file will be opened in append mode.
 #
 from __future__ import absolute_import
 import os
 import sys
 
 try:
     import msvcrt
     msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
     msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
 except ImportError:
     pass
 
 exitcode = 0
 out = sys.stdout
+out = getattr(out, 'buffer', out)
 
 name = sys.argv[1]
 if len(sys.argv) > 2:
     exitcode = int(sys.argv[2])
     if len(sys.argv) > 3:
         out = open(sys.argv[3], "ab")
 
 # variables with empty values may not exist on all platforms, filter
 # them now for portability sake.
 env = [(k, v) for k, v in os.environ.items()
        if k.startswith("HG_") and v]
 env.sort()
 
 out.write(b"%s hook: " % name.encode('ascii'))
 if os.name == 'nt':
     filter = lambda x: x.replace('\\', '/')
 else:
     filter = lambda x: x
 vars = [b"%s=%s" % (k.encode('ascii'), filter(v).encode('ascii'))
         for k, v in env]
 out.write(b" ".join(vars))
 out.write(b"\n")
 out.close()
 
 sys.exit(exitcode)