Normalize string quotes

Convert simple double-quoted strings to single-quoted. Convert triple (single) quoted strings to triple (double) quoted. Do not touch any strings that have backslashes or quotes inside the string.

Fixes psf#51.

setup.py

@@ -4,7 +4,7 @@
 from setuptools import setup
 import sys
 
-assert sys.version_info >= (3, 6, 0), "black requires Python 3.6+"
+assert sys.version_info >= (3, 6, 0), 'black requires Python 3.6+'
 from pathlib import Path  # noqa E402
 
 CURRENT_DIR = Path(__file__).parent
@@ -27,9 +27,9 @@ def get_version():
 setup(
     name='black',
     version=get_version(),
-    description="The uncompromising code formatter.",
+    description='The uncompromising code formatter.',
     long_description=get_long_description(),
-    long_description_content_type="text/markdown",
+    long_description_content_type='text/markdown',
     keywords='automation formatter yapf autopep8 pyfmt gofmt rustfmt',
     author='Łukasz Langa',
     author_email='lukasz@langa.pl',
@@ -38,7 +38,7 @@ def get_version():
     py_modules=['black'],
     packages=['blib2to3', 'blib2to3.pgen2'],
     package_data={'blib2to3': ['*.txt']},
-    python_requires=">=3.6",
+    python_requires='>=3.6',
     zip_safe=False,
     install_requires=['click', 'attrs>=17.4.0'],
     test_suite='tests.test_black',

tests/cantfit.py

@@ -22,6 +22,6 @@
 # long arguments
 normal_name = normal_function_name(
     "but with super long string arguments that on their own exceed the line limit so there's no way it can ever fit",
-    "eggs with spam and eggs and spam with eggs with spam and eggs and spam with eggs with spam and eggs and spam with eggs",
+    'eggs with spam and eggs and spam with eggs with spam and eggs and spam with eggs with spam and eggs and spam with eggs',
     this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it=0,
 )

tests/composition.py

@@ -1,7 +1,7 @@
 class C:
 
     def test(self) -> None:
-        with patch("black.out", print):
+        with patch('black.out', print):
             self.assertEqual(
                 unstyle(str(report)), '1 file reformatted, 1 file failed to reformat.'
             )

tests/empty_lines.py

@@ -64,7 +64,7 @@ def g():
         return DOUBLESPACE
 
     # Another comment because more comments
-    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
+    assert p is not None, f'INTERNAL ERROR: hand-made leaf without parent: {leaf!r}'
 
     prev = leaf.prev_sibling
     if not prev:
@@ -103,7 +103,7 @@ def f():
     if t == token.COMMENT:  # another trailing comment
         return DOUBLESPACE
 
-    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
+    assert p is not None, f'INTERNAL ERROR: hand-made leaf without parent: {leaf!r}'
 
     prev = leaf.prev_sibling
     if not prev:
@@ -155,7 +155,7 @@ def g():
         return DOUBLESPACE
 
     # Another comment because more comments
-    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
+    assert p is not None, f'INTERNAL ERROR: hand-made leaf without parent: {leaf!r}'
 
     prev = leaf.prev_sibling
     if not prev:

tests/fmtonoff.py

@@ -15,10 +15,10 @@ def func_no_args():
   for i in range(10):
     print(i)
     continue
-  exec("new-style exec", {}, {})
+  exec('new-style exec', {}, {})
   return None
 async def coroutine(arg, exec=False):
- "Single-line docstring. Multiline is harder to reformat."
+ '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)
  await asyncio.sleep(1)
@@ -27,7 +27,7 @@ async def coroutine(arg, exec=False):
 with_args=True,
 many_args=[1,2,3]
 )
-def function_signature_stress_test(number:int,no_annotation=None,text:str="default",* ,debug:bool=False,**kwargs) -> str:
+def function_signature_stress_test(number:int,no_annotation=None,text:str='default',* ,debug:bool=False,**kwargs) -> str:
  return text[number:-1]
 # fmt: on
 def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h="", i=r''):
@@ -92,10 +92,10 @@ def func_no_args():
   for i in range(10):
     print(i)
     continue
-  exec("new-style exec", {}, {})
+  exec('new-style exec', {}, {})
   return None
 async def coroutine(arg, exec=False):
- "Single-line docstring. Multiline is harder to reformat."
+ '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)
  await asyncio.sleep(1)
@@ -104,12 +104,12 @@ async def coroutine(arg, exec=False):
 with_args=True,
 many_args=[1,2,3]
 )
-def function_signature_stress_test(number:int,no_annotation=None,text:str="default",* ,debug:bool=False,**kwargs) -> str:
+def function_signature_stress_test(number:int,no_annotation=None,text:str='default',* ,debug:bool=False,**kwargs) -> str:
  return text[number:-1]
 # fmt: on
 
 
-def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h="", i=r''):
+def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h='', i=r''):
     offset = attr.ib(default=attr.Factory(lambda: _r.uniform(10000, 200000)))
     assert task._cancel_stack[:len(old_stack)] == old_stack
 
@@ -122,7 +122,7 @@ def spaces_types(
     e: bool = True,
     f: int = -1,
     g: int = 1 if False else 2,
-    h: str = "",
+    h: str = '',
     i: str = r'',
 ):
     ...

tests/function.py

@@ -96,12 +96,12 @@ def func_no_args():
         print(i)
         continue
 
-    exec("new-style exec", {}, {})
+    exec('new-style exec', {}, {})
     return None
 
 
 async def coroutine(arg, exec=False):
-    "Single-line docstring. Multiline is harder to reformat."
+    '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)
     await asyncio.sleep(1)
@@ -112,15 +112,15 @@ async def coroutine(arg, exec=False):
 def function_signature_stress_test(
     number: int,
     no_annotation=None,
-    text: str = "default",
+    text: str = 'default',
     *,
     debug: bool = False,
     **kwargs,
 ) -> str:
     return text[number:-1]
 
 
-def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h="", i=r''):
+def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h='', i=r''):
     offset = attr.ib(default=attr.Factory(lambda: _r.uniform(10000, 200000)))
     assert task._cancel_stack[:len(old_stack)] == old_stack
 
@@ -133,7 +133,7 @@ def spaces_types(
     e: bool = True,
     f: int = -1,
     g: int = 1 if False else 2,
-    h: str = "",
+    h: str = '',
     i: str = r'',
 ):
     ...

tests/python2.py

@@ -21,9 +21,9 @@ def function((_globals, _locals)):
 
 import sys
 
-print >>sys.stderr, "Warning:",
-print >>sys.stderr, "this is a blast from the past."
-print >>sys.stderr, "Look, a repr:", ` 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)):

tests/string_quotes.py

@@ -0,0 +1,37 @@
+"Hello"
+"Don't do that"
+'Here is a "'
+'What\'s the deal here?'
+"What's the deal \"here\"?"
+"And \"here\"?"
+"""Strings with "" in them"""
+'''Strings with "" in them'''
+'''Here's a "'''
+'''Here's a " '''
+'''Just a normal triple
+quote'''
+f"just a normal {f} string"
+f'''This is a triple-quoted {f}-string'''
+f'MOAR {" ".join([])}'
+f"MOAR {' '.join([])}"
+r"raw string ftw"
+
+# output
+
+"Hello"
+"Don't do that"
+'Here is a "'
+"What's the deal here?"
+'What\'s the deal "here"?'
+'And "here"?'
+"""Strings with "" in them"""
+"""Strings with "" in them"""
+'''Here's a "'''
+"""Here's a " """
+"""Just a normal triple
+quote"""
+f"just a normal {f} string"
+f"""This is a triple-quoted {f}-string"""
+f'MOAR {" ".join([])}'
+f"MOAR {' '.join([])}"
+r"raw string ftw"