contrib: require Python 3.6 for byteify-strings.py

This script makes use of `token.COMMENT`, which apparently
isn't present until Python 3.6. So make the script and its
test conditional on Python 3.6.

contrib/byteify-strings.py

@@ -1,345 +1,345
 #!/usr/bin/env python3
 #
 # byteify-strings.py - transform string literals to be Python 3 safe
 #
 # Copyright 2015 Gregory Szorc <[e-mail]>
 #
 # 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, print_function
 
 import argparse
 import contextlib
 import errno
 import os
 import sys
 import tempfile
 import token
 import tokenize
 
 
 def adjusttokenpos(t, ofs):
     """Adjust start/end column of the given token"""
     return t._replace(
         start=(t.start[0], t.start[1] + ofs), end=(t.end[0], t.end[1] + ofs)
     )
 
 
 def replacetokens(tokens, opts):
     """Transform a stream of tokens from raw to Python 3.
 
     Returns a generator of possibly rewritten tokens.
 
     The input token list may be mutated as part of processing. However,
     its changes do not necessarily match the output token stream.
     """
     sysstrtokens = set()
 
     # The following utility functions access the tokens list and i index of
     # the for i, t enumerate(tokens) loop below
     def _isop(j, *o):
         """Assert that tokens[j] is an OP with one of the given values"""
         try:
             return tokens[j].type == token.OP and tokens[j].string in o
         except IndexError:
             return False
 
     def _findargnofcall(n):
         """Find arg n of a call expression (start at 0)
 
         Returns index of the first token of that argument, or None if
         there is not that many arguments.
 
         Assumes that token[i + 1] is '('.
 
         """
         nested = 0
         for j in range(i + 2, len(tokens)):
             if _isop(j, ')', ']', '}'):
                 # end of call, tuple, subscription or dict / set
                 nested -= 1
                 if nested < 0:
                     return None
             elif n == 0:
                 # this is the starting position of arg
                 return j
             elif _isop(j, '(', '[', '{'):
                 nested += 1
             elif _isop(j, ',') and nested == 0:
                 n -= 1
 
         return None
 
     def _ensuresysstr(j):
         """Make sure the token at j is a system string
 
         Remember the given token so the string transformer won't add
         the byte prefix.
 
         Ignores tokens that are not strings. Assumes bounds checking has
         already been done.
 
         """
         k = j
         currtoken = tokens[k]
         while currtoken.type in (token.STRING, token.NEWLINE, tokenize.NL):
             k += 1
             if currtoken.type == token.STRING and currtoken.string.startswith(
                 ("'", '"')
             ):
                 sysstrtokens.add(currtoken)
             try:
                 currtoken = tokens[k]
             except IndexError:
                 break
 
     def _isitemaccess(j):
         """Assert the next tokens form an item access on `tokens[j]` and that
         `tokens[j]` is a name.
         """
         try:
             return (
                 tokens[j].type == token.NAME
                 and _isop(j + 1, '[')
                 and tokens[j + 2].type == token.STRING
                 and _isop(j + 3, ']')
             )
         except IndexError:
             return False
 
     def _ismethodcall(j, *methodnames):
         """Assert the next tokens form a call to `methodname` with a string
         as first argument on `tokens[j]` and that `tokens[j]` is a name.
         """
         try:
             return (
                 tokens[j].type == token.NAME
                 and _isop(j + 1, '.')
                 and tokens[j + 2].type == token.NAME
                 and tokens[j + 2].string in methodnames
                 and _isop(j + 3, '(')
                 and tokens[j + 4].type == token.STRING
             )
         except IndexError:
             return False
 
     coldelta = 0  # column increment for new opening parens
     coloffset = -1  # column offset for the current line (-1: TBD)
     parens = [(0, 0, 0, -1)]  # stack of (line, end-column, column-offset, type)
     ignorenextline = False  # don't transform the next line
     insideignoreblock = False  # don't transform until turned off
     for i, t in enumerate(tokens):
         # Compute the column offset for the current line, such that
         # the current line will be aligned to the last opening paren
         # as before.
         if coloffset < 0:
             lastparen = parens[-1]
             if t.start[1] == lastparen[1]:
                 coloffset = lastparen[2]
             elif t.start[1] + 1 == lastparen[1] and lastparen[3] not in (
                 token.NEWLINE,
                 tokenize.NL,
             ):
                 # fix misaligned indent of s/util.Abort/error.Abort/
                 coloffset = lastparen[2] + (lastparen[1] - t.start[1])
             else:
                 coloffset = 0
 
         # Reset per-line attributes at EOL.
         if t.type in (token.NEWLINE, tokenize.NL):
             yield adjusttokenpos(t, coloffset)
             coldelta = 0
             coloffset = -1
             if not insideignoreblock:
                 ignorenextline = (
                     tokens[i - 1].type == token.COMMENT
                     and tokens[i - 1].string == "# no-py3-transform"
                 )
             continue
 
         if t.type == token.COMMENT:
             if t.string == "# py3-transform: off":
                 insideignoreblock = True
             if t.string == "# py3-transform: on":
                 insideignoreblock = False
 
         if ignorenextline or insideignoreblock:
             yield adjusttokenpos(t, coloffset)
             continue
 
         # Remember the last paren position.
         if _isop(i, '(', '[', '{'):
             parens.append(t.end + (coloffset + coldelta, tokens[i + 1].type))
         elif _isop(i, ')', ']', '}'):
             parens.pop()
 
         # Convert most string literals to byte literals. String literals
         # in Python 2 are bytes. String literals in Python 3 are unicode.
         # Most strings in Mercurial are bytes and unicode strings are rare.
         # Rather than rewrite all string literals to use ``b''`` to indicate
         # byte strings, we apply this token transformer to insert the ``b``
         # prefix nearly everywhere.
         if t.type == token.STRING and t not in sysstrtokens:
             s = t.string
 
             # Preserve docstrings as string literals. This is inconsistent
             # with regular unprefixed strings. However, the
             # "from __future__" parsing (which allows a module docstring to
             # exist before it) doesn't properly handle the docstring if it
             # is b''' prefixed, leading to a SyntaxError. We leave all
             # docstrings as unprefixed to avoid this. This means Mercurial
             # components touching docstrings need to handle unicode,
             # unfortunately.
             if s[0:3] in ("'''", '"""'):
                 # If it's assigned to something, it's not a docstring
                 if not _isop(i - 1, '='):
                     yield adjusttokenpos(t, coloffset)
                     continue
 
             # If the first character isn't a quote, it is likely a string
             # prefixing character (such as 'b', 'u', or 'r'. Ignore.
             if s[0] not in ("'", '"'):
                 yield adjusttokenpos(t, coloffset)
                 continue
 
             # String literal. Prefix to make a b'' string.
             yield adjusttokenpos(t._replace(string='b%s' % t.string), coloffset)
             coldelta += 1
             continue
 
         # This looks like a function call.
         if t.type == token.NAME and _isop(i + 1, '('):
             fn = t.string
 
             # *attr() builtins don't accept byte strings to 2nd argument.
             if fn in (
                 'getattr',
                 'setattr',
                 'hasattr',
                 'safehasattr',
                 'wrapfunction',
                 'wrapclass',
                 'addattr',
             ) and (opts['allow-attr-methods'] or not _isop(i - 1, '.')):
                 arg1idx = _findargnofcall(1)
                 if arg1idx is not None:
                     _ensuresysstr(arg1idx)
 
             # .encode() and .decode() on str/bytes/unicode don't accept
             # byte strings on Python 3.
             elif fn in ('encode', 'decode') and _isop(i - 1, '.'):
                 for argn in range(2):
                     argidx = _findargnofcall(argn)
                     if argidx is not None:
                         _ensuresysstr(argidx)
 
             # It changes iteritems/values to items/values as they are not
             # present in Python 3 world.
             elif opts['dictiter'] and fn in ('iteritems', 'itervalues'):
                 yield adjusttokenpos(t._replace(string=fn[4:]), coloffset)
                 continue
 
         if t.type == token.NAME and t.string in opts['treat-as-kwargs']:
             if _isitemaccess(i):
                 _ensuresysstr(i + 2)
             if _ismethodcall(i, 'get', 'pop', 'setdefault', 'popitem'):
                 _ensuresysstr(i + 4)
 
         # Looks like "if __name__ == '__main__'".
         if (
             t.type == token.NAME
             and t.string == '__name__'
             and _isop(i + 1, '==')
         ):
             _ensuresysstr(i + 2)
 
         # Emit unmodified token.
         yield adjusttokenpos(t, coloffset)
 
 
 def process(fin, fout, opts):
     tokens = tokenize.tokenize(fin.readline)
     tokens = replacetokens(list(tokens), opts)
     fout.write(tokenize.untokenize(tokens))
 
 
 def tryunlink(fname):
     try:
         os.unlink(fname)
     except OSError as err:
         if err.errno != errno.ENOENT:
             raise
 
 
 @contextlib.contextmanager
 def editinplace(fname):
     n = os.path.basename(fname)
     d = os.path.dirname(fname)
     fp = tempfile.NamedTemporaryFile(
         prefix='.%s-' % n, suffix='~', dir=d, delete=False
     )
     try:
         yield fp
         fp.close()
         if os.name == 'nt':
             tryunlink(fname)
         os.rename(fp.name, fname)
     finally:
         fp.close()
         tryunlink(fp.name)
 
 
 def main():
     ap = argparse.ArgumentParser()
     ap.add_argument(
         '--version', action='version', version='Byteify strings 1.0'
     )
     ap.add_argument(
         '-i',
         '--inplace',
         action='store_true',
         default=False,
         help='edit files in place',
     )
     ap.add_argument(
         '--dictiter',
         action='store_true',
         default=False,
         help='rewrite iteritems() and itervalues()',
     ),
     ap.add_argument(
         '--allow-attr-methods',
         action='store_true',
         default=False,
         help='also handle attr*() when they are methods',
     ),
     ap.add_argument(
         '--treat-as-kwargs',
         nargs="+",
         default=[],
         help="ignore kwargs-like objects",
     ),
     ap.add_argument('files', metavar='FILE', nargs='+', help='source file')
     args = ap.parse_args()
     opts = {
         'dictiter': args.dictiter,
         'treat-as-kwargs': set(args.treat_as_kwargs),
         'allow-attr-methods': args.allow_attr_methods,
     }
     for fname in args.files:
         if args.inplace:
             with editinplace(fname) as fout:
                 with open(fname, 'rb') as fin:
                     process(fin, fout, opts)
         else:
             with open(fname, 'rb') as fin:
                 fout = sys.stdout.buffer
                 process(fin, fout, opts)
 
 
 if __name__ == '__main__':
-    if sys.version_info.major < 3:
-        print('This script must be run under Python 3.')
+    if sys.version_info[0:2] < (3, 6):
+        print('This script must be run under Python 3.6+')
         sys.exit(3)
     main()

tests/test-byteify-strings.t

@@ -1,266 +1,266
-#require py3
+#require py36
 
   $ byteify_strings () {
   >   $PYTHON "$TESTDIR/../contrib/byteify-strings.py" "$@"
   > }
 
 Test version
 
   $ byteify_strings --version
   Byteify strings * (glob)
 
 Test in-place
 
   $ cat > testfile.py <<EOF
   > obj['test'] = b"1234"
   > mydict.iteritems()
   > EOF
   $ byteify_strings testfile.py -i
   $ cat testfile.py
   obj[b'test'] = b"1234"
   mydict.iteritems()
 
 Test with dictiter
 
   $ cat > testfile.py <<EOF
   > obj['test'] = b"1234"
   > mydict.iteritems()
   > EOF
   $ byteify_strings testfile.py --dictiter
   obj[b'test'] = b"1234"
   mydict.items()
 
 Test kwargs-like objects
 
   $ cat > testfile.py <<EOF
   > kwargs['test'] = "123"
   > kwargs[test['testing']]
   > kwargs[test[[['testing']]]]
   > kwargs[kwargs['testing']]
   > kwargs.get('test')
   > kwargs.pop('test')
   > kwargs.get('test', 'testing')
   > kwargs.pop('test', 'testing')
   > kwargs.setdefault('test', 'testing')
   > 
   > opts['test'] = "123"
   > opts[test['testing']]
   > opts[test[[['testing']]]]
   > opts[opts['testing']]
   > opts.get('test')
   > opts.pop('test')
   > opts.get('test', 'testing')
   > opts.pop('test', 'testing')
   > opts.setdefault('test', 'testing')
   > 
   > commitopts['test'] = "123"
   > commitopts[test['testing']]
   > commitopts[test[[['testing']]]]
   > commitopts[commitopts['testing']]
   > commitopts.get('test')
   > commitopts.pop('test')
   > commitopts.get('test', 'testing')
   > commitopts.pop('test', 'testing')
   > commitopts.setdefault('test', 'testing')
   > EOF
   $ byteify_strings testfile.py --treat-as-kwargs kwargs opts commitopts
   kwargs['test'] = b"123"
   kwargs[test[b'testing']]
   kwargs[test[[[b'testing']]]]
   kwargs[kwargs['testing']]
   kwargs.get('test')
   kwargs.pop('test')
   kwargs.get('test', b'testing')
   kwargs.pop('test', b'testing')
   kwargs.setdefault('test', b'testing')
   
   opts['test'] = b"123"
   opts[test[b'testing']]
   opts[test[[[b'testing']]]]
   opts[opts['testing']]
   opts.get('test')
   opts.pop('test')
   opts.get('test', b'testing')
   opts.pop('test', b'testing')
   opts.setdefault('test', b'testing')
   
   commitopts['test'] = b"123"
   commitopts[test[b'testing']]
   commitopts[test[[[b'testing']]]]
   commitopts[commitopts['testing']]
   commitopts.get('test')
   commitopts.pop('test')
   commitopts.get('test', b'testing')
   commitopts.pop('test', b'testing')
   commitopts.setdefault('test', b'testing')
 
 Test attr*() as methods
 
   $ cat > testfile.py <<EOF
   > setattr(o, 'a', 1)
   > util.setattr(o, 'ae', 1)
   > util.getattr(o, 'alksjdf', 'default')
   > util.addattr(o, 'asdf')
   > util.hasattr(o, 'lksjdf', 'default')
   > util.safehasattr(o, 'lksjdf', 'default')
   > @eh.wrapfunction(func, 'lksjdf')
   > def f():
   >     pass
   > @eh.wrapclass(klass, 'lksjdf')
   > def f():
   >     pass
   > EOF
   $ byteify_strings testfile.py --allow-attr-methods
   setattr(o, 'a', 1)
   util.setattr(o, 'ae', 1)
   util.getattr(o, 'alksjdf', b'default')
   util.addattr(o, 'asdf')
   util.hasattr(o, 'lksjdf', b'default')
   util.safehasattr(o, 'lksjdf', b'default')
   @eh.wrapfunction(func, 'lksjdf')
   def f():
       pass
   @eh.wrapclass(klass, 'lksjdf')
   def f():
       pass
 
 Test without attr*() as methods
 
   $ cat > testfile.py <<EOF
   > setattr(o, 'a', 1)
   > util.setattr(o, 'ae', 1)
   > util.getattr(o, 'alksjdf', 'default')
   > util.addattr(o, 'asdf')
   > util.hasattr(o, 'lksjdf', 'default')
   > util.safehasattr(o, 'lksjdf', 'default')
   > @eh.wrapfunction(func, 'lksjdf')
   > def f():
   >     pass
   > @eh.wrapclass(klass, 'lksjdf')
   > def f():
   >     pass
   > EOF
   $ byteify_strings testfile.py
   setattr(o, 'a', 1)
   util.setattr(o, b'ae', 1)
   util.getattr(o, b'alksjdf', b'default')
   util.addattr(o, b'asdf')
   util.hasattr(o, b'lksjdf', b'default')
   util.safehasattr(o, b'lksjdf', b'default')
   @eh.wrapfunction(func, b'lksjdf')
   def f():
       pass
   @eh.wrapclass(klass, b'lksjdf')
   def f():
       pass
 
 Test ignore comments
 
   $ cat > testfile.py <<EOF
   > # py3-transform: off
   > "none"
   > "of"
   > 'these'
   > s = """should"""
   > d = '''be'''
   > # py3-transform: on
   > "this should"
   > 'and this also'
   > 
   > # no-py3-transform
   > l = "this should be ignored"
   > l2 = "this shouldn't"
   > 
   > EOF
   $ byteify_strings testfile.py
   # py3-transform: off
   "none"
   "of"
   'these'
   s = """should"""
   d = '''be'''
   # py3-transform: on
   b"this should"
   b'and this also'
   
   # no-py3-transform
   l = "this should be ignored"
   l2 = b"this shouldn't"
   
 Test triple-quoted strings
 
   $ cat > testfile.py <<EOF
   > """This is ignored
   > """
   > 
   > line = """
   >   This should not be
   > """
   > line = '''
   > Neither should this
   > '''
   > EOF
   $ byteify_strings testfile.py
   """This is ignored
   """
   
   line = b"""
     This should not be
   """
   line = b'''
   Neither should this
   '''
 
 Test prefixed strings
 
   $ cat > testfile.py <<EOF
   > obj['test'] = b"1234"
   > obj[r'test'] = u"1234"
   > EOF
   $ byteify_strings testfile.py
   obj[b'test'] = b"1234"
   obj[r'test'] = u"1234"
 
 Test multi-line alignment
 
   $ cat > testfile.py <<'EOF'
   > def foo():
   >     error.Abort(_("foo"
   >                  "bar"
   >                  "%s")
   >                % parameter)
   > {
   >     'test': dict,
   >     'test2': dict,
   > }
   > [
   >    "thing",
   >    "thing2"
   > ]
   > (
   >    "tuple",
   >    "tuple2",
   > )
   > {"thing",
   >  }
   > EOF
   $ byteify_strings testfile.py
   def foo():
       error.Abort(_(b"foo"
                     b"bar"
                     b"%s")
                   % parameter)
   {
       b'test': dict,
       b'test2': dict,
   }
   [
      b"thing",
      b"thing2"
   ]
   (
      b"tuple",
      b"tuple2",
   )
   {b"thing",
    }