323 lines
13 KiB
Python
323 lines
13 KiB
Python
"""
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futurize: automatic conversion to clean 2/3 code using ``python-future``
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======================================================================
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Like Armin Ronacher's modernize.py, ``futurize`` attempts to produce clean
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standard Python 3 code that runs on both Py2 and Py3.
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One pass
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--------
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Use it like this on Python 2 code:
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$ futurize --verbose mypython2script.py
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This will attempt to port the code to standard Py3 code that also
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provides Py2 compatibility with the help of the right imports from
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``future``.
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To write changes to the files, use the -w flag.
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Two stages
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----------
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The ``futurize`` script can also be called in two separate stages. First:
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$ futurize --stage1 mypython2script.py
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This produces more modern Python 2 code that is not yet compatible with Python
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3. The tests should still run and the diff should be uncontroversial to apply to
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most Python projects that are willing to drop support for Python 2.5 and lower.
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After this, the recommended approach is to explicitly mark all strings that must
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be byte-strings with a b'' prefix and all text (unicode) strings with a u''
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prefix, and then invoke the second stage of Python 2 to 2/3 conversion with::
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$ futurize --stage2 mypython2script.py
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Stage 2 adds a dependency on ``future``. It converts most remaining Python
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2-specific code to Python 3 code and adds appropriate imports from ``future``
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to restore Py2 support.
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The command above leaves all unadorned string literals as native strings
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(byte-strings on Py2, unicode strings on Py3). If instead you would like all
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unadorned string literals to be promoted to unicode, you can also pass this
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flag:
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$ futurize --stage2 --unicode-literals mypython2script.py
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This adds the declaration ``from __future__ import unicode_literals`` to the
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top of each file, which implicitly declares all unadorned string literals to be
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unicode strings (``unicode`` on Py2).
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All imports
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-----------
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The --all-imports option forces adding all ``__future__`` imports,
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``builtins`` imports, and standard library aliases, even if they don't
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seem necessary for the current state of each module. (This can simplify
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testing, and can reduce the need to think about Py2 compatibility when editing
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the code further.)
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"""
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from __future__ import (absolute_import, print_function, unicode_literals)
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import future.utils
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from future import __version__
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import sys
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import logging
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import optparse
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import os
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from lib2to3.main import warn, StdoutRefactoringTool
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from lib2to3 import refactor
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from libfuturize.fixes import (lib2to3_fix_names_stage1,
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lib2to3_fix_names_stage2,
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libfuturize_fix_names_stage1,
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libfuturize_fix_names_stage2)
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fixer_pkg = 'libfuturize.fixes'
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def main(args=None):
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"""Main program.
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Args:
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fixer_pkg: the name of a package where the fixers are located.
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args: optional; a list of command line arguments. If omitted,
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sys.argv[1:] is used.
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Returns a suggested exit status (0, 1, 2).
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"""
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# Set up option parser
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parser = optparse.OptionParser(usage="futurize [options] file|dir ...")
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parser.add_option("-V", "--version", action="store_true",
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help="Report the version number of futurize")
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parser.add_option("-a", "--all-imports", action="store_true",
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help="Add all __future__ and future imports to each module")
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parser.add_option("-1", "--stage1", action="store_true",
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help="Modernize Python 2 code only; no compatibility with Python 3 (or dependency on ``future``)")
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parser.add_option("-2", "--stage2", action="store_true",
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help="Take modernized (stage1) code and add a dependency on ``future`` to provide Py3 compatibility.")
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parser.add_option("-0", "--both-stages", action="store_true",
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help="Apply both stages 1 and 2")
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parser.add_option("-u", "--unicode-literals", action="store_true",
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help="Add ``from __future__ import unicode_literals`` to implicitly convert all unadorned string literals '' into unicode strings")
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parser.add_option("-f", "--fix", action="append", default=[],
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help="Each FIX specifies a transformation; default: all.\nEither use '-f division -f metaclass' etc. or use the fully-qualified module name: '-f lib2to3.fixes.fix_types -f libfuturize.fixes.fix_unicode_keep_u'")
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parser.add_option("-j", "--processes", action="store", default=1,
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type="int", help="Run 2to3 concurrently")
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parser.add_option("-x", "--nofix", action="append", default=[],
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help="Prevent a fixer from being run.")
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parser.add_option("-l", "--list-fixes", action="store_true",
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help="List available transformations")
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parser.add_option("-p", "--print-function", action="store_true",
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help="Modify the grammar so that print() is a function")
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parser.add_option("-v", "--verbose", action="store_true",
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help="More verbose logging")
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parser.add_option("--no-diffs", action="store_true",
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help="Don't show diffs of the refactoring")
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parser.add_option("-w", "--write", action="store_true",
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help="Write back modified files")
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parser.add_option("-n", "--nobackups", action="store_true", default=False,
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help="Don't write backups for modified files.")
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parser.add_option("-o", "--output-dir", action="store", type="str",
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default="", help="Put output files in this directory "
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"instead of overwriting the input files. Requires -n. "
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"For Python >= 2.7 only.")
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parser.add_option("-W", "--write-unchanged-files", action="store_true",
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help="Also write files even if no changes were required"
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" (useful with --output-dir); implies -w.")
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parser.add_option("--add-suffix", action="store", type="str", default="",
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help="Append this string to all output filenames."
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" Requires -n if non-empty. For Python >= 2.7 only."
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"ex: --add-suffix='3' will generate .py3 files.")
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# Parse command line arguments
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flags = {}
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refactor_stdin = False
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options, args = parser.parse_args(args)
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if options.write_unchanged_files:
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flags["write_unchanged_files"] = True
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if not options.write:
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warn("--write-unchanged-files/-W implies -w.")
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options.write = True
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# If we allowed these, the original files would be renamed to backup names
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# but not replaced.
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if options.output_dir and not options.nobackups:
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parser.error("Can't use --output-dir/-o without -n.")
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if options.add_suffix and not options.nobackups:
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parser.error("Can't use --add-suffix without -n.")
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if not options.write and options.no_diffs:
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warn("not writing files and not printing diffs; that's not very useful")
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if not options.write and options.nobackups:
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parser.error("Can't use -n without -w")
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if "-" in args:
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refactor_stdin = True
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if options.write:
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print("Can't write to stdin.", file=sys.stderr)
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return 2
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# Is this ever necessary?
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if options.print_function:
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flags["print_function"] = True
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# Set up logging handler
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level = logging.DEBUG if options.verbose else logging.INFO
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logging.basicConfig(format='%(name)s: %(message)s', level=level)
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logger = logging.getLogger('libfuturize.main')
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if options.stage1 or options.stage2:
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assert options.both_stages is None
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options.both_stages = False
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else:
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options.both_stages = True
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avail_fixes = set()
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if options.stage1 or options.both_stages:
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avail_fixes.update(lib2to3_fix_names_stage1)
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avail_fixes.update(libfuturize_fix_names_stage1)
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if options.stage2 or options.both_stages:
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avail_fixes.update(lib2to3_fix_names_stage2)
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avail_fixes.update(libfuturize_fix_names_stage2)
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if options.unicode_literals:
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avail_fixes.add('libfuturize.fixes.fix_unicode_literals_import')
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if options.version:
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print(__version__)
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return 0
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if options.list_fixes:
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print("Available transformations for the -f/--fix option:")
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# for fixname in sorted(refactor.get_all_fix_names(fixer_pkg)):
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for fixname in sorted(avail_fixes):
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print(fixname)
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if not args:
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return 0
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if not args:
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print("At least one file or directory argument required.",
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file=sys.stderr)
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print("Use --help to show usage.", file=sys.stderr)
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return 2
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unwanted_fixes = set()
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for fix in options.nofix:
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if ".fix_" in fix:
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unwanted_fixes.add(fix)
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else:
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# Infer the full module name for the fixer.
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# First ensure that no names clash (e.g.
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# lib2to3.fixes.fix_blah and libfuturize.fixes.fix_blah):
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found = [f for f in avail_fixes
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if f.endswith('fix_{0}'.format(fix))]
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if len(found) > 1:
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print("Ambiguous fixer name. Choose a fully qualified "
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"module name instead from these:\n" +
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"\n".join(" " + myf for myf in found),
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file=sys.stderr)
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return 2
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elif len(found) == 0:
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print("Unknown fixer. Use --list-fixes or -l for a list.",
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file=sys.stderr)
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return 2
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unwanted_fixes.add(found[0])
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extra_fixes = set()
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if options.all_imports:
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if options.stage1:
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prefix = 'libfuturize.fixes.'
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extra_fixes.add(prefix +
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'fix_add__future__imports_except_unicode_literals')
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else:
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# In case the user hasn't run stage1 for some reason:
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prefix = 'libpasteurize.fixes.'
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extra_fixes.add(prefix + 'fix_add_all__future__imports')
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extra_fixes.add(prefix + 'fix_add_future_standard_library_import')
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extra_fixes.add(prefix + 'fix_add_all_future_builtins')
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explicit = set()
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if options.fix:
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all_present = False
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for fix in options.fix:
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if fix == 'all':
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all_present = True
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else:
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if ".fix_" in fix:
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explicit.add(fix)
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else:
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# Infer the full module name for the fixer.
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# First ensure that no names clash (e.g.
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# lib2to3.fixes.fix_blah and libfuturize.fixes.fix_blah):
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found = [f for f in avail_fixes
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if f.endswith('fix_{0}'.format(fix))]
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if len(found) > 1:
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print("Ambiguous fixer name. Choose a fully qualified "
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"module name instead from these:\n" +
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"\n".join(" " + myf for myf in found),
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file=sys.stderr)
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return 2
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elif len(found) == 0:
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print("Unknown fixer. Use --list-fixes or -l for a list.",
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file=sys.stderr)
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return 2
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explicit.add(found[0])
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if len(explicit & unwanted_fixes) > 0:
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print("Conflicting usage: the following fixers have been "
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"simultaneously requested and disallowed:\n" +
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"\n".join(" " + myf for myf in (explicit & unwanted_fixes)),
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file=sys.stderr)
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return 2
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requested = avail_fixes.union(explicit) if all_present else explicit
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else:
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requested = avail_fixes.union(explicit)
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fixer_names = (requested | extra_fixes) - unwanted_fixes
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input_base_dir = os.path.commonprefix(args)
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if (input_base_dir and not input_base_dir.endswith(os.sep)
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and not os.path.isdir(input_base_dir)):
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# One or more similar names were passed, their directory is the base.
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# os.path.commonprefix() is ignorant of path elements, this corrects
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# for that weird API.
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input_base_dir = os.path.dirname(input_base_dir)
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if options.output_dir:
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input_base_dir = input_base_dir.rstrip(os.sep)
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logger.info('Output in %r will mirror the input directory %r layout.',
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options.output_dir, input_base_dir)
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# Initialize the refactoring tool
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if future.utils.PY26:
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extra_kwargs = {}
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else:
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extra_kwargs = {
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'append_suffix': options.add_suffix,
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'output_dir': options.output_dir,
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'input_base_dir': input_base_dir,
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}
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rt = StdoutRefactoringTool(
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sorted(fixer_names), flags, sorted(explicit),
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options.nobackups, not options.no_diffs,
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**extra_kwargs)
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# Refactor all files and directories passed as arguments
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if not rt.errors:
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if refactor_stdin:
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rt.refactor_stdin()
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else:
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try:
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rt.refactor(args, options.write, None,
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options.processes)
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except refactor.MultiprocessingUnsupported:
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assert options.processes > 1
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print("Sorry, -j isn't " \
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"supported on this platform.", file=sys.stderr)
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return 1
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rt.summarize()
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# Return error status (0 if rt.errors is zero)
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return int(bool(rt.errors))
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