Add flake8 to CI, too

[etc/vim.git] / black.py

diff --git a/black.py b/black.py
index 774d91dc2a7f64ec2dbc252a55e0fe051d5c429c..48ba0a266cc7c5354f87ec30c13600aed8528599 100644 (file)
--- a/black.py
+++ b/black.py
@@ -7,6 +7,7 @@ import keyword
 import os
 from pathlib import Path
 import tokenize
 import os
 from pathlib import Path
 import tokenize

+import sys

 from typing import (
     Dict, Generic, Iterable, Iterator, List, Optional, Set, Tuple, TypeVar, Union
 )
 from typing import (
     Dict, Generic, Iterable, Iterator, List, Optional, Set, Tuple, TypeVar, Union
 )


@@ -20,7 +21,7 @@ from blib2to3 import pygram, pytree
 from blib2to3.pgen2 import driver, token
 from blib2to3.pgen2.parse import ParseError
 
 from blib2to3.pgen2 import driver, token
 from blib2to3.pgen2.parse import ParseError
 

-__version__ = "18.3a1"
+__version__ = "18.3a2"

 DEFAULT_LINE_LENGTH = 88
 # types
 syms = pygram.python_symbols
 DEFAULT_LINE_LENGTH = 88
 # types
 syms = pygram.python_symbols


@@ -192,6 +193,7 @@ def format_str(src_contents: str, line_length: int) -> FileContent:
     comments: List[Line] = []
     lines = LineGenerator()
     elt = EmptyLineTracker()
     comments: List[Line] = []
     lines = LineGenerator()
     elt = EmptyLineTracker()

+    py36 = is_python36(src_node)

     empty_line = Line()
     after = 0
     for current_line in lines.visit(src_node):
     empty_line = Line()
     after = 0
     for current_line in lines.visit(src_node):


@@ -204,7 +206,7 @@ def format_str(src_contents: str, line_length: int) -> FileContent:
             for comment in comments:
                 dst_contents += str(comment)
             comments = []
             for comment in comments:
                 dst_contents += str(comment)
             comments = []

-            for line in split_line(current_line, line_length=line_length):
+            for line in split_line(current_line, line_length=line_length, py36=py36):

                 dst_contents += str(line)
         else:
             comments.append(current_line)
                 dst_contents += str(line)
         else:
             comments.append(current_line)


@@ -345,8 +347,8 @@ class BracketTracker:
         if leaf.type in CLOSING_BRACKETS:
             self.depth -= 1
             opening_bracket = self.bracket_match.pop((self.depth, leaf.type))
         if leaf.type in CLOSING_BRACKETS:
             self.depth -= 1
             opening_bracket = self.bracket_match.pop((self.depth, leaf.type))

-            leaf.opening_bracket = opening_bracket  # type: ignore
-        leaf.bracket_depth = self.depth  # type: ignore
+            leaf.opening_bracket = opening_bracket
+        leaf.bracket_depth = self.depth

         if self.depth == 0:
             delim = is_delimiter(leaf)
             if delim:
         if self.depth == 0:
             delim = is_delimiter(leaf)
             if delim:


@@ -489,9 +491,9 @@ class Line:
         # For parens let's check if it's safe to remove the comma.  If the
         # trailing one is the only one, we might mistakenly change a tuple
         # into a different type by removing the comma.
         # For parens let's check if it's safe to remove the comma.  If the
         # trailing one is the only one, we might mistakenly change a tuple
         # into a different type by removing the comma.

-        depth = closing.bracket_depth + 1  # type: ignore
+        depth = closing.bracket_depth + 1

         commas = 0
         commas = 0

-        opening = closing.opening_bracket  # type: ignore
+        opening = closing.opening_bracket

         for _opening_index, leaf in enumerate(self.leaves):
             if leaf is opening:
                 break
         for _opening_index, leaf in enumerate(self.leaves):
             if leaf is opening:
                 break


@@ -503,7 +505,7 @@ class Line:
             if leaf is closing:
                 break
 
             if leaf is closing:
                 break
 

-            bracket_depth = leaf.bracket_depth  # type: ignore
+            bracket_depth = leaf.bracket_depth

             if bracket_depth == depth and leaf.type == token.COMMA:
                 commas += 1
         if commas > 1:
             if bracket_depth == depth and leaf.type == token.COMMA:
                 commas += 1
         if commas > 1:


@@ -802,9 +804,10 @@ BRACKET = {token.LPAR: token.RPAR, token.LSQB: token.RSQB, token.LBRACE: token.R
 OPENING_BRACKETS = set(BRACKET.keys())
 CLOSING_BRACKETS = set(BRACKET.values())
 BRACKETS = OPENING_BRACKETS | CLOSING_BRACKETS
 OPENING_BRACKETS = set(BRACKET.keys())
 CLOSING_BRACKETS = set(BRACKET.values())
 BRACKETS = OPENING_BRACKETS | CLOSING_BRACKETS

+ALWAYS_NO_SPACE = CLOSING_BRACKETS | {token.COMMA, token.COLON, STANDALONE_COMMENT}

 
 
 
 

-def whitespace(leaf: Leaf) -> str:
+def whitespace(leaf: Leaf) -> str:  # noqa C901

     """Return whitespace prefix if needed for the given `leaf`."""
     NO = ''
     SPACE = ' '
     """Return whitespace prefix if needed for the given `leaf`."""
     NO = ''
     SPACE = ' '


@@ -812,24 +815,12 @@ def whitespace(leaf: Leaf) -> str:
     t = leaf.type
     p = leaf.parent
     v = leaf.value
     t = leaf.type
     p = leaf.parent
     v = leaf.value

-    if t == token.COLON:
-        return NO
-
-    if t == token.COMMA:
-        return NO
-
-    if t == token.RPAR:
+    if t in ALWAYS_NO_SPACE:

         return NO
 
     if t == token.COMMENT:
         return DOUBLESPACE
 
         return NO
 
     if t == token.COMMENT:
         return DOUBLESPACE
 

-    if t == STANDALONE_COMMENT:
-        return NO
-
-    if t in CLOSING_BRACKETS:
-        return NO
-

     assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
     prev = leaf.prev_sibling
     if not prev:
     assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
     prev = leaf.prev_sibling
     if not prev:


@@ -861,7 +852,7 @@ def whitespace(leaf: Leaf) -> str:
             if prevp.parent and prevp.parent.type == syms.subscript:
                 return NO
 
             if prevp.parent and prevp.parent.type == syms.subscript:
                 return NO
 

-        elif prevp.parent and prevp.parent.type == syms.factor:
+        elif prevp.parent and prevp.parent.type in {syms.factor, syms.star_expr}:

             return NO
 
     elif prev.type in OPENING_BRACKETS:
             return NO
 
     elif prev.type in OPENING_BRACKETS:


@@ -958,7 +949,14 @@ def whitespace(leaf: Leaf) -> str:
 
     elif p.type == syms.subscript:
         # indexing
 
     elif p.type == syms.subscript:
         # indexing

-        if not prev or prev.type == token.COLON:
+        if not prev:
+            assert p.parent is not None, "subscripts are always parented"
+            if p.parent.type == syms.subscriptlist:
+                return SPACE
+
+            return NO
+
+        elif prev.type == token.COLON:

             return NO
 
     elif p.type == syms.atom:
             return NO
 
     elif p.type == syms.atom:


@@ -983,7 +981,7 @@ def whitespace(leaf: Leaf) -> str:
         if prev.type == token.DOUBLESTAR:
             return NO
 
         if prev.type == token.DOUBLESTAR:
             return NO
 

-    elif p.type == syms.factor or p.type == syms.star_expr:
+    elif p.type in {syms.factor, syms.star_expr}:

         # unary ops
         if not prev:
             prevp = preceding_leaf(p)
         # unary ops
         if not prev:
             prevp = preceding_leaf(p)


@@ -1108,13 +1106,18 @@ def generate_comments(leaf: Leaf) -> Iterator[Leaf]:
         yield Leaf(STANDALONE_COMMENT, line)
 
 
         yield Leaf(STANDALONE_COMMENT, line)
 
 

-def split_line(line: Line, line_length: int, inner: bool = False) -> Iterator[Line]:
+def split_line(
+    line: Line, line_length: int, inner: bool = False, py36: bool = False
+) -> Iterator[Line]:

     """Splits a `line` into potentially many lines.
 
     They should fit in the allotted `line_length` but might not be able to.
     `inner` signifies that there were a pair of brackets somewhere around the
     current `line`, possibly transitively. This means we can fallback to splitting
     by delimiters if the LHS/RHS don't yield any results.
     """Splits a `line` into potentially many lines.
 
     They should fit in the allotted `line_length` but might not be able to.
     `inner` signifies that there were a pair of brackets somewhere around the
     current `line`, possibly transitively. This means we can fallback to splitting
     by delimiters if the LHS/RHS don't yield any results.

+
+    If `py36` is True, splitting may generate syntax that is only compatible
+    with Python 3.6 and later.

     """
     line_str = str(line).strip('\n')
     if len(line_str) <= line_length and '\n' not in line_str:
     """
     line_str = str(line).strip('\n')
     if len(line_str) <= line_length and '\n' not in line_str:


@@ -1137,11 +1140,13 @@ def split_line(line: Line, line_length: int, inner: bool = False) -> Iterator[Li
         # split altogether.
         result: List[Line] = []
         try:
         # split altogether.
         result: List[Line] = []
         try:

-            for l in split_func(line):
+            for l in split_func(line, py36=py36):

                 if str(l).strip('\n') == line_str:
                     raise CannotSplit("Split function returned an unchanged result")
 
                 if str(l).strip('\n') == line_str:
                     raise CannotSplit("Split function returned an unchanged result")
 

-                result.extend(split_line(l, line_length=line_length, inner=True))
+                result.extend(
+                    split_line(l, line_length=line_length, inner=True, py36=py36)
+                )

         except CannotSplit as cs:
             continue
 
         except CannotSplit as cs:
             continue
 


@@ -1153,7 +1158,7 @@ def split_line(line: Line, line_length: int, inner: bool = False) -> Iterator[Li
         yield line
 
 
         yield line
 
 

-def left_hand_split(line: Line) -> Iterator[Line]:
+def left_hand_split(line: Line, py36: bool = False) -> Iterator[Line]:

     """Split line into many lines, starting with the first matching bracket pair.
 
     Note: this usually looks weird, only use this for function definitions.
     """Split line into many lines, starting with the first matching bracket pair.
 
     Note: this usually looks weird, only use this for function definitions.


@@ -1171,7 +1176,7 @@ def left_hand_split(line: Line) -> Iterator[Line]:
         if (
             current_leaves is body_leaves and
             leaf.type in CLOSING_BRACKETS and
         if (
             current_leaves is body_leaves and
             leaf.type in CLOSING_BRACKETS and

-            leaf.opening_bracket is matching_bracket  # type: ignore
+            leaf.opening_bracket is matching_bracket

         ):
             current_leaves = tail_leaves
         current_leaves.append(leaf)
         ):
             current_leaves = tail_leaves
         current_leaves.append(leaf)


@@ -1208,7 +1213,7 @@ def left_hand_split(line: Line) -> Iterator[Line]:
             yield result
 
 
             yield result
 
 

-def right_hand_split(line: Line) -> Iterator[Line]:
+def right_hand_split(line: Line, py36: bool = False) -> Iterator[Line]:

     """Split line into many lines, starting with the last matching bracket pair."""
     head = Line(depth=line.depth)
     body = Line(depth=line.depth + 1, inside_brackets=True)
     """Split line into many lines, starting with the last matching bracket pair."""
     head = Line(depth=line.depth)
     body = Line(depth=line.depth + 1, inside_brackets=True)


@@ -1225,7 +1230,7 @@ def right_hand_split(line: Line) -> Iterator[Line]:
         current_leaves.append(leaf)
         if current_leaves is tail_leaves:
             if leaf.type in CLOSING_BRACKETS:
         current_leaves.append(leaf)
         if current_leaves is tail_leaves:
             if leaf.type in CLOSING_BRACKETS:

-                opening_bracket = leaf.opening_bracket  # type: ignore
+                opening_bracket = leaf.opening_bracket

                 current_leaves = body_leaves
     tail_leaves.reverse()
     body_leaves.reverse()
                 current_leaves = body_leaves
     tail_leaves.reverse()
     body_leaves.reverse()


@@ -1259,10 +1264,12 @@ def right_hand_split(line: Line) -> Iterator[Line]:
             yield result
 
 
             yield result
 
 

-def delimiter_split(line: Line) -> Iterator[Line]:
+def delimiter_split(line: Line, py36: bool = False) -> Iterator[Line]:

     """Split according to delimiters of the highest priority.
 
     This kind of split doesn't increase indentation.
     """Split according to delimiters of the highest priority.
 
     This kind of split doesn't increase indentation.

+    If `py36` is True, the split will add trailing commas also in function
+    signatures that contain * and **.

     """
     try:
         last_leaf = line.leaves[-1]
     """
     try:
         last_leaf = line.leaves[-1]


@@ -1276,11 +1283,20 @@ def delimiter_split(line: Line) -> Iterator[Line]:
         raise CannotSplit("No delimiters found")
 
     current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)
         raise CannotSplit("No delimiters found")
 
     current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)

+    lowest_depth = sys.maxsize
+    trailing_comma_safe = True

     for leaf in line.leaves:
         current_line.append(leaf, preformatted=True)
         comment_after = line.comments.get(id(leaf))
         if comment_after:
             current_line.append(comment_after, preformatted=True)
     for leaf in line.leaves:
         current_line.append(leaf, preformatted=True)
         comment_after = line.comments.get(id(leaf))
         if comment_after:
             current_line.append(comment_after, preformatted=True)

+        lowest_depth = min(lowest_depth, leaf.bracket_depth)
+        if (
+            leaf.bracket_depth == lowest_depth and
+            leaf.type == token.STAR or
+            leaf.type == token.DOUBLESTAR
+        ):
+            trailing_comma_safe = trailing_comma_safe and py36

         leaf_priority = delimiters.get(id(leaf))
         if leaf_priority == delimiter_priority:
             normalize_prefix(current_line.leaves[0])
         leaf_priority = delimiters.get(id(leaf))
         if leaf_priority == delimiter_priority:
             normalize_prefix(current_line.leaves[0])


@@ -1290,7 +1306,8 @@ def delimiter_split(line: Line) -> Iterator[Line]:
     if current_line:
         if (
             delimiter_priority == COMMA_PRIORITY and
     if current_line:
         if (
             delimiter_priority == COMMA_PRIORITY and

-            current_line.leaves[-1].type != token.COMMA
+            current_line.leaves[-1].type != token.COMMA and
+            trailing_comma_safe

         ):
             current_line.append(Leaf(token.COMMA, ','))
         normalize_prefix(current_line.leaves[0])
         ):
             current_line.append(Leaf(token.COMMA, ','))
         normalize_prefix(current_line.leaves[0])


@@ -1325,6 +1342,31 @@ def normalize_prefix(leaf: Leaf) -> None:
     leaf.prefix = ''
 
 
     leaf.prefix = ''
 
 

+def is_python36(node: Node) -> bool:
+    """Returns True if the current file is using Python 3.6+ features.
+
+    Currently looking for:
+    - f-strings; and
+    - trailing commas after * or ** in function signatures.
+    """
+    for n in node.pre_order():
+        if n.type == token.STRING:
+            value_head = n.value[:2]  # type: ignore
+            if value_head in {'f"', 'F"', "f'", "F'", 'rf', 'fr', 'RF', 'FR'}:
+                return True
+
+        elif (
+            n.type == syms.typedargslist and
+            n.children and
+            n.children[-1].type == token.COMMA
+        ):
+            for ch in n.children:
+                if ch.type == token.STAR or ch.type == token.DOUBLESTAR:
+                    return True
+
+    return False
+
+

 PYTHON_EXTENSIONS = {'.py'}
 BLACKLISTED_DIRECTORIES = {
     'build', 'buck-out', 'dist', '_build', '.git', '.hg', '.mypy_cache', '.tox', '.venv'
 PYTHON_EXTENSIONS = {'.py'}
 BLACKLISTED_DIRECTORIES = {
     'build', 'buck-out', 'dist', '_build', '.git', '.hg', '.mypy_cache', '.tox', '.venv'