From: Łukasz Langa Date: Fri, 23 Mar 2018 06:17:40 +0000 (-0700) Subject: Automatic detection of deprecated Python 2 forms of print and exec X-Git-Url: https://git.madduck.net/etc/vim.git/commitdiff_plain/6316e293ac30a2837ec20eba289fd28a2a18cf89?ds=sidebyside;hp=8de552eb4f0fbf1ad84812cde71489cc00d3ed1f Automatic detection of deprecated Python 2 forms of print and exec Note: if those are handled, you can't use --safe because this check is using Python 3.6+ builtin AST. Fixes #49 --- diff --git a/README.md b/README.md index 951948f..3558254 100644 --- a/README.md +++ b/README.md @@ -275,8 +275,7 @@ python setup.py test But you can reformat Python 2 code with it, too. *Black* is able to parse all of the new syntax supported on Python 3.6 but also *effectively all* -the Python 2 syntax at the same time, as long as you're not using print -statements. +the Python 2 syntax at the same time. By making the code exclusively Python 3.6+, I'm able to focus on the quality of the formatting and re-use all the nice features of the new @@ -309,6 +308,9 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md). ### 18.3a4 (unreleased) +* automatic detection of deprecated Python 2 forms of print statements + and exec statements in the formatted file (#49) + * only return exit code 1 when --check is used (#50) * don't remove single trailing commas from square bracket indexing diff --git a/black.py b/black.py index bb8ec2e..7935cdc 100644 --- a/black.py +++ b/black.py @@ -235,23 +235,36 @@ def format_str(src_contents: str, line_length: int) -> FileContent: return dst_contents +GRAMMARS = [ + pygram.python_grammar_no_print_statement_no_exec_statement, + pygram.python_grammar_no_print_statement, + pygram.python_grammar_no_exec_statement, + pygram.python_grammar, +] + + def lib2to3_parse(src_txt: str) -> Node: """Given a string with source, return the lib2to3 Node.""" grammar = pygram.python_grammar_no_print_statement - drv = driver.Driver(grammar, pytree.convert) if src_txt[-1] != '\n': nl = '\r\n' if '\r\n' in src_txt[:1024] else '\n' src_txt += nl - try: - result = drv.parse_string(src_txt, True) - except ParseError as pe: - lineno, column = pe.context[1] - lines = src_txt.splitlines() + for grammar in GRAMMARS: + drv = driver.Driver(grammar, pytree.convert) try: - faulty_line = lines[lineno - 1] - except IndexError: - faulty_line = "" - raise ValueError(f"Cannot parse: {lineno}:{column}: {faulty_line}") from None + result = drv.parse_string(src_txt, True) + break + + except ParseError as pe: + lineno, column = pe.context[1] + lines = src_txt.splitlines() + try: + faulty_line = lines[lineno - 1] + except IndexError: + faulty_line = "" + exc = ValueError(f"Cannot parse: {lineno}:{column}: {faulty_line}") + else: + raise exc from None if isinstance(result, Leaf): result = Node(syms.file_input, [result]) @@ -903,6 +916,17 @@ def whitespace(leaf: Leaf) -> str: # noqa C901 ): return NO + elif ( + prevp.type == token.RIGHTSHIFT + and prevp.parent + and prevp.parent.type == syms.shift_expr + and prevp.prev_sibling + and prevp.prev_sibling.type == token.NAME + and prevp.prev_sibling.value == 'print' + ): + # Python 2 print chevron + return NO + elif prev.type in OPENING_BRACKETS: return NO @@ -1538,7 +1562,12 @@ def assert_equivalent(src: str, dst: str) -> None: try: src_ast = ast.parse(src) except Exception as exc: - raise AssertionError(f"cannot parse source: {exc}") from None + major, minor = sys.version_info[:2] + raise AssertionError( + f"cannot use --safe with this file; failed to parse source file " + f"with Python {major}.{minor}'s builtin AST. Re-run with --fast " + f"or stop using deprecated Python 2 syntax. AST error message: {exc}" + ) try: dst_ast = ast.parse(dst) diff --git a/blib2to3/pygram.py b/blib2to3/pygram.py index c4ff9d1..bf55ab4 100644 --- a/blib2to3/pygram.py +++ b/blib2to3/pygram.py @@ -36,5 +36,12 @@ python_symbols = Symbols(python_grammar) python_grammar_no_print_statement = python_grammar.copy() del python_grammar_no_print_statement.keywords["print"] +python_grammar_no_exec_statement = python_grammar.copy() +del python_grammar_no_exec_statement.keywords["exec"] + +python_grammar_no_print_statement_no_exec_statement = python_grammar.copy() +del python_grammar_no_print_statement_no_exec_statement.keywords["print"] +del python_grammar_no_print_statement_no_exec_statement.keywords["exec"] + pattern_grammar = driver.load_packaged_grammar("blib2to3", _PATTERN_GRAMMAR_FILE) pattern_symbols = Symbols(pattern_grammar) diff --git a/blib2to3/pygram.pyi b/blib2to3/pygram.pyi index 3dbc648..5f134d5 100644 --- a/blib2to3/pygram.pyi +++ b/blib2to3/pygram.pyi @@ -116,4 +116,6 @@ class pattern_symbols(Symbols): python_grammar: Grammar python_grammar_no_print_statement: Grammar +python_grammar_no_print_statement_no_exec_statement: Grammar +python_grammar_no_exec_statement: Grammar pattern_grammar: Grammar diff --git a/tests/function.py b/tests/function.py index 7fa6866..888ef9f 100644 --- a/tests/function.py +++ b/tests/function.py @@ -14,8 +14,9 @@ def func_no_args(): for i in range(10): print(i) continue + exec("new-style exec", {}, {}) return None -async def coroutine(arg): +async def coroutine(arg, exec=False): "Single-line docstring. Multiline is harder to reformat." async with some_connection() as conn: await conn.do_what_i_mean('SELECT bobby, tables FROM xkcd', timeout=2) @@ -93,10 +94,11 @@ def func_no_args(): print(i) continue + exec("new-style exec", {}, {}) return None -async def coroutine(arg): +async def coroutine(arg, exec=False): "Single-line docstring. Multiline is harder to reformat." async with some_connection() as conn: await conn.do_what_i_mean('SELECT bobby, tables FROM xkcd', timeout=2) diff --git a/tests/python2.py b/tests/python2.py new file mode 100644 index 0000000..5214add --- /dev/null +++ b/tests/python2.py @@ -0,0 +1,33 @@ +#!/usr/bin/env python2 + +import sys + +print >> sys.stderr , "Warning:" , +print >> sys.stderr , "this is a blast from the past." +print >> sys.stderr , "Look, a repr:", `sys` + + +def function((_globals, _locals)): + exec "print 'hi from exec!'" in _globals, _locals + + +function((globals(), locals())) + + +# output + + +#!/usr/bin/env python2 + +import sys + +print >>sys.stderr, "Warning:", +print >>sys.stderr, "this is a blast from the past." +print >>sys.stderr, "Look, a repr:", ` sys ` + + +def function((_globals, _locals)): + exec "print 'hi from exec!'" in _globals, _locals + + +function((globals(), locals())) diff --git a/tests/test_black.py b/tests/test_black.py index 69746d1..3415549 100644 --- a/tests/test_black.py +++ b/tests/test_black.py @@ -180,6 +180,14 @@ class BlackTestCase(unittest.TestCase): black.assert_equivalent(source, actual) black.assert_stable(source, actual, line_length=ll) + @patch("black.dump_to_file", dump_to_stderr) + def test_python2(self) -> None: + source, expected = read_data('python2') + actual = fs(source) + self.assertFormatEqual(expected, actual) + # black.assert_equivalent(source, actual) + black.assert_stable(source, actual, line_length=ll) + def test_report(self) -> None: report = black.Report() out_lines = []