not enforcing python3.6 for precommit hook (#430)

[etc/vim.git] / black.py

diff --git a/black.py b/black.py
index 7682f7c393776a1b75be292e36f6620fed8925a3..b66ad0d00b9e7c1574011c5146c8f6e380488973 100644 (file)
--- a/black.py
+++ b/black.py
@@ -20,6 +20,7 @@ from typing import (
     Callable,
     Collection,
     Dict,
     Callable,
     Collection,
     Dict,

+    Generator,

     Generic,
     Iterable,
     Iterator,
     Generic,
     Iterable,
     Iterator,


@@ -29,7 +30,6 @@ from typing import (
     Sequence,
     Set,
     Tuple,
     Sequence,
     Set,
     Tuple,

-    Type,

     TypeVar,
     Union,
     cast,
     TypeVar,
     Union,
     cast,


@@ -47,7 +47,7 @@ from blib2to3.pgen2 import driver, token
 from blib2to3.pgen2.parse import ParseError
 
 
 from blib2to3.pgen2.parse import ParseError
 
 

-__version__ = "18.6b2"
+__version__ = "18.6b4"

 DEFAULT_LINE_LENGTH = 88
 DEFAULT_EXCLUDES = (
     r"/(\.git|\.hg|\.mypy_cache|\.tox|\.venv|_build|buck-out|build|dist)/"
 DEFAULT_LINE_LENGTH = 88
 DEFAULT_EXCLUDES = (
     r"/(\.git|\.hg|\.mypy_cache|\.tox|\.venv|_build|buck-out|build|dist)/"


@@ -90,43 +90,16 @@ class CannotSplit(Exception):
     """
 
 
     """
 
 

-class FormatError(Exception):
-    """Base exception for `# fmt: on` and `# fmt: off` handling.
-
-    It holds the number of bytes of the prefix consumed before the format
-    control comment appeared.
-    """
-
-    def __init__(self, consumed: int) -> None:
-        super().__init__(consumed)
-        self.consumed = consumed
-
-    def trim_prefix(self, leaf: Leaf) -> None:
-        leaf.prefix = leaf.prefix[self.consumed :]
-
-    def leaf_from_consumed(self, leaf: Leaf) -> Leaf:
-        """Returns a new Leaf from the consumed part of the prefix."""
-        unformatted_prefix = leaf.prefix[: self.consumed]
-        return Leaf(token.NEWLINE, unformatted_prefix)
-
-
-class FormatOn(FormatError):
-    """Found a comment like `# fmt: on` in the file."""
-
-
-class FormatOff(FormatError):
-    """Found a comment like `# fmt: off` in the file."""
-
-

 class WriteBack(Enum):
     NO = 0
     YES = 1
     DIFF = 2
 class WriteBack(Enum):
     NO = 0
     YES = 1
     DIFF = 2

+    CHECK = 3

 
     @classmethod
     def from_configuration(cls, *, check: bool, diff: bool) -> "WriteBack":
         if check and not diff:
 
     @classmethod
     def from_configuration(cls, *, check: bool, diff: bool) -> "WriteBack":
         if check and not diff:

-            return cls.NO
+            return cls.CHECK

 
         return cls.DIFF if diff else cls.YES
 
 
         return cls.DIFF if diff else cls.YES
 


@@ -426,7 +399,14 @@ def reformat_one(
                 mode=mode,
             ):
                 changed = Changed.YES
                 mode=mode,
             ):
                 changed = Changed.YES

-            if write_back == WriteBack.YES and changed is not Changed.NO:
+            if write_back is WriteBack.YES:
+                should_write = changed is not Changed.CACHED
+            elif write_back is WriteBack.CHECK:
+                should_write = changed is Changed.NO
+            else:
+                should_write = False
+
+            if should_write:

                 write_cache(cache, [src], line_length, mode)
         report.done(src, changed)
     except Exception as exc:
                 write_cache(cache, [src], line_length, mode)
         report.done(src, changed)
     except Exception as exc:


@@ -494,11 +474,17 @@ async def schedule_formatting(
                 elif task.exception():
                     report.failed(src, str(task.exception()))
                 else:
                 elif task.exception():
                     report.failed(src, str(task.exception()))
                 else:

-                    formatted.append(src)
-                    report.done(src, Changed.YES if task.result() else Changed.NO)
+                    changed = Changed.YES if task.result() else Changed.NO
+                    # In normal mode, write all files to the cache.
+                    if write_back is WriteBack.YES:
+                        formatted.append(src)
+                    # In check mode, write only unchanged files to the cache.
+                    elif write_back is WriteBack.CHECK and changed is Changed.NO:
+                        formatted.append(src)
+                    report.done(src, changed)

     if cancelled:
         await asyncio.gather(*cancelled, loop=loop, return_exceptions=True)
     if cancelled:
         await asyncio.gather(*cancelled, loop=loop, return_exceptions=True)

-    if write_back == WriteBack.YES and formatted:
+    if write_back in (WriteBack.YES, WriteBack.CHECK) and formatted:

         write_cache(cache, formatted, line_length, mode)
 
 
         write_cache(cache, formatted, line_length, mode)
 
 


@@ -512,7 +498,8 @@ def format_file_in_place(
 ) -> bool:
     """Format file under `src` path. Return True if changed.
 
 ) -> bool:
     """Format file under `src` path. Return True if changed.
 

-    If `write_back` is True, write reformatted code back to stdout.
+    If `write_back` is DIFF, write a diff to stdout. If it is YES, write reformatted
+    code to the file.

     `line_length` and `fast` options are passed to :func:`format_file_contents`.
     """
     if src.suffix == ".pyi":
     `line_length` and `fast` options are passed to :func:`format_file_contents`.
     """
     if src.suffix == ".pyi":


@@ -561,7 +548,8 @@ def format_stdin_to_stdout(
 ) -> bool:
     """Format file on stdin. Return True if changed.
 
 ) -> bool:
     """Format file on stdin. Return True if changed.
 

-    If `write_back` is True, write reformatted code back to stdout.
+    If `write_back` is YES, write reformatted code back to stdout. If it is DIFF,
+    write a diff to stdout.

     `line_length`, `fast`, `is_pyi`, and `force_py36` arguments are passed to
     :func:`format_file_contents`.
     """
     `line_length`, `fast`, `is_pyi`, and `force_py36` arguments are passed to
     :func:`format_file_contents`.
     """


@@ -633,6 +621,7 @@ def format_str(
         remove_u_prefix=py36 or "unicode_literals" in future_imports,
         is_pyi=is_pyi,
         normalize_strings=normalize_strings,
         remove_u_prefix=py36 or "unicode_literals" in future_imports,
         is_pyi=is_pyi,
         normalize_strings=normalize_strings,

+        allow_underscores=py36,

     )
     elt = EmptyLineTracker(is_pyi=is_pyi)
     empty_line = Line()
     )
     elt = EmptyLineTracker(is_pyi=is_pyi)
     empty_line = Line()


@@ -759,13 +748,15 @@ class DebugVisitor(Visitor[T]):
             out(f" {node.value!r}", fg="blue", bold=False)
 
     @classmethod
             out(f" {node.value!r}", fg="blue", bold=False)
 
     @classmethod

-    def show(cls, code: str) -> None:
+    def show(cls, code: Union[str, Leaf, Node]) -> None:

         """Pretty-print the lib2to3 AST of a given string of `code`.
 
         Convenience method for debugging.
         """
         v: DebugVisitor[None] = DebugVisitor()
         """Pretty-print the lib2to3 AST of a given string of `code`.
 
         Convenience method for debugging.
         """
         v: DebugVisitor[None] = DebugVisitor()

-        list(v.visit(lib2to3_parse(code)))
+        if isinstance(code, str):
+            code = lib2to3_parse(code)
+        list(v.visit(code))

 
 
 KEYWORDS = set(keyword.kwlist)
 
 
 KEYWORDS = set(keyword.kwlist)


@@ -823,18 +814,6 @@ UNPACKING_PARENTS = {
     syms.testlist_gexp,
     syms.testlist_star_expr,
 }
     syms.testlist_gexp,
     syms.testlist_star_expr,
 }

-SURROUNDED_BY_BRACKETS = {
-    syms.typedargslist,
-    syms.arglist,
-    syms.subscriptlist,
-    syms.vfplist,
-    syms.import_as_names,
-    syms.yield_expr,
-    syms.testlist_gexp,
-    syms.testlist_star_expr,
-    syms.listmaker,
-    syms.dictsetmaker,
-}

 TEST_DESCENDANTS = {
     syms.test,
     syms.lambdef,
 TEST_DESCENDANTS = {
     syms.test,
     syms.lambdef,


@@ -1306,55 +1285,6 @@ class Line:
         return bool(self.leaves or self.comments)
 
 
         return bool(self.leaves or self.comments)
 
 

-class UnformattedLines(Line):
-    """Just like :class:`Line` but stores lines which aren't reformatted."""
-
-    def append(self, leaf: Leaf, preformatted: bool = True) -> None:
-        """Just add a new `leaf` to the end of the lines.
-
-        The `preformatted` argument is ignored.
-
-        Keeps track of indentation `depth`, which is useful when the user
-        says `# fmt: on`. Otherwise, doesn't do anything with the `leaf`.
-        """
-        try:
-            list(generate_comments(leaf))
-        except FormatOn as f_on:
-            self.leaves.append(f_on.leaf_from_consumed(leaf))
-            raise
-
-        self.leaves.append(leaf)
-        if leaf.type == token.INDENT:
-            self.depth += 1
-        elif leaf.type == token.DEDENT:
-            self.depth -= 1
-
-    def __str__(self) -> str:
-        """Render unformatted lines from leaves which were added with `append()`.
-
-        `depth` is not used for indentation in this case.
-        """
-        if not self:
-            return "\n"
-
-        res = ""
-        for leaf in self.leaves:
-            res += str(leaf)
-        return res
-
-    def append_comment(self, comment: Leaf) -> bool:
-        """Not implemented in this class. Raises `NotImplementedError`."""
-        raise NotImplementedError("Unformatted lines don't store comments separately.")
-
-    def maybe_remove_trailing_comma(self, closing: Leaf) -> bool:
-        """Does nothing and returns False."""
-        return False
-
-    def maybe_increment_for_loop_variable(self, leaf: Leaf) -> bool:
-        """Does nothing and returns False."""
-        return False
-
-

 @dataclass
 class EmptyLineTracker:
     """Provides a stateful method that returns the number of potential extra
 @dataclass
 class EmptyLineTracker:
     """Provides a stateful method that returns the number of potential extra


@@ -1376,9 +1306,6 @@ class EmptyLineTracker:
         This is for separating `def`, `async def` and `class` with extra empty
         lines (two on module-level).
         """
         This is for separating `def`, `async def` and `class` with extra empty
         lines (two on module-level).
         """

-        if isinstance(current_line, UnformattedLines):
-            return 0, 0
-

         before, after = self._maybe_empty_lines(current_line)
         before -= self.previous_after
         self.previous_after = after
         before, after = self._maybe_empty_lines(current_line)
         before -= self.previous_after
         self.previous_after = after


@@ -1481,8 +1408,9 @@ class LineGenerator(Visitor[Line]):
     normalize_strings: bool = True
     current_line: Line = Factory(Line)
     remove_u_prefix: bool = False
     normalize_strings: bool = True
     current_line: Line = Factory(Line)
     remove_u_prefix: bool = False

+    allow_underscores: bool = False

 
 

-    def line(self, indent: int = 0, type: Type[Line] = Line) -> Iterator[Line]:
+    def line(self, indent: int = 0) -> Iterator[Line]:

         """Generate a line.
 
         If the line is empty, only emit if it makes sense.
         """Generate a line.
 
         If the line is empty, only emit if it makes sense.


@@ -1491,67 +1419,41 @@ class LineGenerator(Visitor[Line]):
         If any lines were generated, set up a new current_line.
         """
         if not self.current_line:
         If any lines were generated, set up a new current_line.
         """
         if not self.current_line:

-            if self.current_line.__class__ == type:
-                self.current_line.depth += indent
-            else:
-                self.current_line = type(depth=self.current_line.depth + indent)
+            self.current_line.depth += indent

             return  # Line is empty, don't emit. Creating a new one unnecessary.
 
         complete_line = self.current_line
             return  # Line is empty, don't emit. Creating a new one unnecessary.
 
         complete_line = self.current_line

-        self.current_line = type(depth=complete_line.depth + indent)
+        self.current_line = Line(depth=complete_line.depth + indent)

         yield complete_line
 
         yield complete_line
 

-    def visit(self, node: LN) -> Iterator[Line]:
-        """Main method to visit `node` and its children.
-
-        Yields :class:`Line` objects.
-        """
-        if isinstance(self.current_line, UnformattedLines):
-            # File contained `# fmt: off`
-            yield from self.visit_unformatted(node)
-
-        else:
-            yield from super().visit(node)
-

     def visit_default(self, node: LN) -> Iterator[Line]:
         """Default `visit_*()` implementation. Recurses to children of `node`."""
         if isinstance(node, Leaf):
             any_open_brackets = self.current_line.bracket_tracker.any_open_brackets()
     def visit_default(self, node: LN) -> Iterator[Line]:
         """Default `visit_*()` implementation. Recurses to children of `node`."""
         if isinstance(node, Leaf):
             any_open_brackets = self.current_line.bracket_tracker.any_open_brackets()

-            try:
-                for comment in generate_comments(node):
-                    if any_open_brackets:
-                        # any comment within brackets is subject to splitting
-                        self.current_line.append(comment)
-                    elif comment.type == token.COMMENT:
-                        # regular trailing comment
-                        self.current_line.append(comment)
-                        yield from self.line()
-
-                    else:
-                        # regular standalone comment
-                        yield from self.line()
-
-                        self.current_line.append(comment)
-                        yield from self.line()
-
-            except FormatOff as f_off:
-                f_off.trim_prefix(node)
-                yield from self.line(type=UnformattedLines)
-                yield from self.visit(node)
-
-            except FormatOn as f_on:
-                # This only happens here if somebody says "fmt: on" multiple
-                # times in a row.
-                f_on.trim_prefix(node)
-                yield from self.visit_default(node)
+            for comment in generate_comments(node):
+                if any_open_brackets:
+                    # any comment within brackets is subject to splitting
+                    self.current_line.append(comment)
+                elif comment.type == token.COMMENT:
+                    # regular trailing comment
+                    self.current_line.append(comment)
+                    yield from self.line()

 
 

-            else:
-                normalize_prefix(node, inside_brackets=any_open_brackets)
-                if self.normalize_strings and node.type == token.STRING:
-                    normalize_string_prefix(node, remove_u_prefix=self.remove_u_prefix)
-                    normalize_string_quotes(node)
-                if node.type not in WHITESPACE:
-                    self.current_line.append(node)
+                else:
+                    # regular standalone comment
+                    yield from self.line()
+
+                    self.current_line.append(comment)
+                    yield from self.line()
+
+            normalize_prefix(node, inside_brackets=any_open_brackets)
+            if self.normalize_strings and node.type == token.STRING:
+                normalize_string_prefix(node, remove_u_prefix=self.remove_u_prefix)
+                normalize_string_quotes(node)
+            if node.type == token.NUMBER:
+                normalize_numeric_literal(node, self.allow_underscores)
+            if node.type not in WHITESPACE:
+                self.current_line.append(node)

         yield from super().visit_default(node)
 
     def visit_INDENT(self, node: Node) -> Iterator[Line]:
         yield from super().visit_default(node)
 
     def visit_INDENT(self, node: Node) -> Iterator[Line]:


@@ -1648,23 +1550,10 @@ class LineGenerator(Visitor[Line]):
         yield from self.visit_default(leaf)
         yield from self.line()
 
         yield from self.visit_default(leaf)
         yield from self.line()
 

-    def visit_unformatted(self, node: LN) -> Iterator[Line]:
-        """Used when file contained a `# fmt: off`."""
-        if isinstance(node, Node):
-            for child in node.children:
-                yield from self.visit(child)
-
-        else:
-            try:
-                self.current_line.append(node)
-            except FormatOn as f_on:
-                f_on.trim_prefix(node)
-                yield from self.line()
-                yield from self.visit(node)
-
-            if node.type == token.ENDMARKER:
-                # somebody decided not to put a final `# fmt: on`
-                yield from self.line()
+    def visit_STANDALONE_COMMENT(self, leaf: Leaf) -> Iterator[Line]:
+        if not self.current_line.bracket_tracker.any_open_brackets():
+            yield from self.line()
+        yield from self.visit_default(leaf)

 
     def __attrs_post_init__(self) -> None:
         """You are in a twisty little maze of passages."""
 
     def __attrs_post_init__(self) -> None:
         """You are in a twisty little maze of passages."""


@@ -1969,7 +1858,10 @@ def container_of(leaf: Leaf) -> LN:
         if parent.children[0].prefix != same_prefix:
             break
 
         if parent.children[0].prefix != same_prefix:
             break
 

-        if parent.type in SURROUNDED_BY_BRACKETS:
+        if parent.type == syms.file_input:
+            break
+
+        if parent.prev_sibling is not None and parent.prev_sibling.type in BRACKETS:

             break
 
         container = parent
             break
 
         container = parent


@@ -2106,16 +1998,6 @@ def generate_comments(leaf: LN) -> Iterator[Leaf]:
     """
     for pc in list_comments(leaf.prefix, is_endmarker=leaf.type == token.ENDMARKER):
         yield Leaf(pc.type, pc.value, prefix="\n" * pc.newlines)
     """
     for pc in list_comments(leaf.prefix, is_endmarker=leaf.type == token.ENDMARKER):
         yield Leaf(pc.type, pc.value, prefix="\n" * pc.newlines)

-        if pc.value in FMT_ON:
-            raise FormatOn(pc.consumed)
-
-        if pc.value in FMT_OFF:
-            if pc.type == STANDALONE_COMMENT:
-                raise FormatOff(pc.consumed)
-
-            prev = preceding_leaf(leaf)
-            if not prev or prev.type in WHITESPACE:  # standalone comment in disguise
-                raise FormatOff(pc.consumed)

 
 
 @dataclass
 
 
 @dataclass


@@ -2188,7 +2070,7 @@ def split_line(
     If `py36` is True, splitting may generate syntax that is only compatible
     with Python 3.6 and later.
     """
     If `py36` is True, splitting may generate syntax that is only compatible
     with Python 3.6 and later.
     """

-    if isinstance(line, UnformattedLines) or line.is_comment:
+    if line.is_comment:

         yield line
         return
 
         yield line
         return
 


@@ -2631,6 +2513,61 @@ def normalize_string_quotes(leaf: Leaf) -> None:
     leaf.value = f"{prefix}{new_quote}{new_body}{new_quote}"
 
 
     leaf.value = f"{prefix}{new_quote}{new_body}{new_quote}"
 
 

+def normalize_numeric_literal(leaf: Leaf, allow_underscores: bool) -> None:
+    """Normalizes numeric (float, int, and complex) literals."""
+    # We want all letters (e in exponents, j in complex literals, a-f
+    # in hex literals) to be lowercase.
+    text = leaf.value.lower()
+    if text.startswith(("0o", "0x", "0b")):
+        # Leave octal, hex, and binary literals alone for now.
+        pass
+    elif "e" in text:
+        before, after = text.split("e")
+        if after.startswith("-"):
+            after = after[1:]
+            sign = "-"
+        elif after.startswith("+"):
+            after = after[1:]
+            sign = ""
+        else:
+            sign = ""
+        before = format_float_or_int_string(before, allow_underscores)
+        after = format_int_string(after, allow_underscores)
+        text = f"{before}e{sign}{after}"
+    # Complex numbers and Python 2 longs
+    elif "j" in text or "l" in text:
+        number = text[:-1]
+        suffix = text[-1]
+        text = f"{format_float_or_int_string(number, allow_underscores)}{suffix}"
+    else:
+        text = format_float_or_int_string(text, allow_underscores)
+    leaf.value = text
+
+
+def format_float_or_int_string(text: str, allow_underscores: bool) -> str:
+    """Formats a float string like "1.0"."""
+    if "." not in text:
+        return format_int_string(text, allow_underscores)
+    before, after = text.split(".")
+    before = format_int_string(before, allow_underscores) if before else "0"
+    after = format_int_string(after, allow_underscores) if after else "0"
+    return f"{before}.{after}"
+
+
+def format_int_string(text: str, allow_underscores: bool) -> str:
+    """Normalizes underscores in a string to e.g. 1_000_000.
+
+    Input must be a string consisting only of digits and underscores.
+    """
+    if not allow_underscores:
+        return text
+    text = text.replace("_", "")
+    if len(text) <= 6:
+        # No underscores for numbers <= 6 digits long.
+        return text
+    return format(int(text), "3_")
+
+

 def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None:
     """Make existing optional parentheses invisible or create new ones.
 
 def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None:
     """Make existing optional parentheses invisible or create new ones.
 


@@ -2680,29 +2617,33 @@ def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None:
 
 
 def normalize_fmt_off(node: Node) -> None:
 
 
 def normalize_fmt_off(node: Node) -> None:

-    """Allow `# fmt: off`/`# fmt: on` within bracket pairs.
-
-    Ignores `# fmt: off` and `# fmt: on` outside of brackets.
-
-    Raises :exc:`SyntaxError` if no matching `# fmt: on` is found for a `# fmt: off`
-    given inside brackets.
-    """
+    """Convert content between `# fmt: off`/`# fmt: on` into standalone comments."""

     try_again = True
     while try_again:
     try_again = True
     while try_again:

-        try_again = hide_fmt_off(node)
+        try_again = convert_one_fmt_off_pair(node)

 
 
 
 

-def hide_fmt_off(node: Node) -> bool:
-    bt = BracketTracker()
-    for leaf in node.leaves():
-        bt.mark(leaf)
-        if bt.depth == 0:
-            continue
+def convert_one_fmt_off_pair(node: Node) -> bool:
+    """Convert content of a single `# fmt: off`/`# fmt: on` into a standalone comment.

 
 

+    Returns True if a pair was converted.
+    """
+    for leaf in node.leaves():

         previous_consumed = 0
         for comment in list_comments(leaf.prefix, is_endmarker=False):
             if comment.value in FMT_OFF:
         previous_consumed = 0
         for comment in list_comments(leaf.prefix, is_endmarker=False):
             if comment.value in FMT_OFF:

+                # We only want standalone comments. If there's no previous leaf or
+                # the previous leaf is indentation, it's a standalone comment in
+                # disguise.
+                if comment.type != STANDALONE_COMMENT:
+                    prev = preceding_leaf(leaf)
+                    if prev and prev.type not in WHITESPACE:
+                        continue
+

                 ignored_nodes = list(generate_ignored_nodes(leaf))
                 ignored_nodes = list(generate_ignored_nodes(leaf))

+                if not ignored_nodes:
+                    continue
+

                 first = ignored_nodes[0]  # Can be a container node with the `leaf`.
                 parent = first.parent
                 prefix = first.prefix
                 first = ignored_nodes[0]  # Can be a container node with the `leaf`.
                 parent = first.parent
                 prefix = first.prefix


@@ -2710,6 +2651,10 @@ def hide_fmt_off(node: Node) -> bool:
                 hidden_value = (
                     comment.value + "\n" + "".join(str(n) for n in ignored_nodes)
                 )
                 hidden_value = (
                     comment.value + "\n" + "".join(str(n) for n in ignored_nodes)
                 )

+                if hidden_value.endswith("\n"):
+                    # That happens when one of the `ignored_nodes` ended with a NEWLINE
+                    # leaf (possibly followed by a DEDENT).
+                    hidden_value = hidden_value[:-1]

                 first_idx = None
                 for ignored in ignored_nodes:
                     index = ignored.remove()
                 first_idx = None
                 for ignored in ignored_nodes:
                     index = ignored.remove()


@@ -2727,14 +2672,18 @@ def hide_fmt_off(node: Node) -> bool:
                 )
                 return True
 
                 )
                 return True
 

-            previous_consumed += comment.consumed
+            previous_consumed = comment.consumed

 
     return False
 
 
 def generate_ignored_nodes(leaf: Leaf) -> Iterator[LN]:
 
     return False
 
 
 def generate_ignored_nodes(leaf: Leaf) -> Iterator[LN]:

+    """Starting from the container of `leaf`, generate all leaves until `# fmt: on`.
+
+    Stops at the end of the block.
+    """

     container: Optional[LN] = container_of(leaf)
     container: Optional[LN] = container_of(leaf)

-    while container is not None:
+    while container is not None and container.type != token.ENDMARKER:

         for comment in list_comments(container.prefix, is_endmarker=False):
             if comment.value in FMT_ON:
                 return
         for comment in list_comments(container.prefix, is_endmarker=False):
             if comment.value in FMT_ON:
                 return


@@ -3025,7 +2974,23 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
 
 def get_future_imports(node: Node) -> Set[str]:
     """Return a set of __future__ imports in the file."""
 
 def get_future_imports(node: Node) -> Set[str]:
     """Return a set of __future__ imports in the file."""

-    imports = set()
+    imports: Set[str] = set()
+
+    def get_imports_from_children(children: List[LN]) -> Generator[str, None, None]:
+        for child in children:
+            if isinstance(child, Leaf):
+                if child.type == token.NAME:
+                    yield child.value
+            elif child.type == syms.import_as_name:
+                orig_name = child.children[0]
+                assert isinstance(orig_name, Leaf), "Invalid syntax parsing imports"
+                assert orig_name.type == token.NAME, "Invalid syntax parsing imports"
+                yield orig_name.value
+            elif child.type == syms.import_as_names:
+                yield from get_imports_from_children(child.children)
+            else:
+                assert False, "Invalid syntax parsing imports"
+

     for child in node.children:
         if child.type != syms.simple_stmt:
             break
     for child in node.children:
         if child.type != syms.simple_stmt:
             break


@@ -3044,15 +3009,7 @@ def get_future_imports(node: Node) -> Set[str]:
             module_name = first_child.children[1]
             if not isinstance(module_name, Leaf) or module_name.value != "__future__":
                 break
             module_name = first_child.children[1]
             if not isinstance(module_name, Leaf) or module_name.value != "__future__":
                 break

-            for import_from_child in first_child.children[3:]:
-                if isinstance(import_from_child, Leaf):
-                    if import_from_child.type == token.NAME:
-                        imports.add(import_from_child.value)
-                else:
-                    assert import_from_child.type == syms.import_as_names
-                    for leaf in import_from_child.children:
-                        if isinstance(leaf, Leaf) and leaf.type == token.NAME:
-                            imports.add(leaf.value)
+            imports |= set(get_imports_from_children(first_child.children[3:]))

         else:
             break
     return imports
         else:
             break
     return imports


@@ -3068,7 +3025,7 @@ def gen_python_files_in_dir(
     """Generate all files under `path` whose paths are not excluded by the
     `exclude` regex, but are included by the `include` regex.
 
     """Generate all files under `path` whose paths are not excluded by the
     `exclude` regex, but are included by the `include` regex.
 

-    Symbolic links pointing outside of the root directory are ignored.
+    Symbolic links pointing outside of the `root` directory are ignored.

 
     `report` is where output about exclusions goes.
     """
 
     `report` is where output about exclusions goes.
     """


@@ -3079,8 +3036,7 @@ def gen_python_files_in_dir(
         except ValueError:
             if child.is_symlink():
                 report.path_ignored(
         except ValueError:
             if child.is_symlink():
                 report.path_ignored(

-                    child,
-                    "is a symbolic link that points outside of the root directory",
+                    child, f"is a symbolic link that points outside {root}"

                 )
                 continue
 
                 )
                 continue
 


@@ -3600,5 +3556,28 @@ def write_cache(
         pass
 
 
         pass
 
 

+def patch_click() -> None:
+    """Make Click not crash.
+
+    On certain misconfigured environments, Python 3 selects the ASCII encoding as the
+    default which restricts paths that it can access during the lifetime of the
+    application.  Click refuses to work in this scenario by raising a RuntimeError.
+
+    In case of Black the likelihood that non-ASCII characters are going to be used in
+    file paths is minimal since it's Python source code.  Moreover, this crash was
+    spurious on Python 3.7 thanks to PEP 538 and PEP 540.
+    """
+    try:
+        from click import core
+        from click import _unicodefun  # type: ignore
+    except ModuleNotFoundError:
+        return
+
+    for module in (core, _unicodefun):
+        if hasattr(module, "_verify_python3_env"):
+            module._verify_python3_env = lambda: None
+
+

 if __name__ == "__main__":
 if __name__ == "__main__":

+    patch_click()

     main()
     main()