readme: Include Zulip in used-by section (#1987)

[etc/vim.git] / src / black / __init__.py

diff --git a/src/black/__init__.py b/src/black/__init__.py
index e09838d866a1f3071079858fc12afc70575cdff8..6dbb765cf7a488afcf0a1289e1fc681caaa3a9e5 100644 (file)
--- a/src/black/__init__.py
+++ b/src/black/__init__.py
@@ -42,7 +42,6 @@ from typing import (
     cast,
     TYPE_CHECKING,
 )
     cast,
     TYPE_CHECKING,
 )

-from typing_extensions import Final

 from mypy_extensions import mypyc_attr
 
 from appdirs import user_cache_dir
 from mypy_extensions import mypyc_attr
 
 from appdirs import user_cache_dir


@@ -61,6 +60,11 @@ from blib2to3.pgen2.parse import ParseError
 
 from _black_version import version as __version__
 
 
 from _black_version import version as __version__
 

+if sys.version_info < (3, 8):
+    from typing_extensions import Final
+else:
+    from typing import Final
+

 if TYPE_CHECKING:
     import colorama  # noqa: F401
 
 if TYPE_CHECKING:
     import colorama  # noqa: F401
 


@@ -68,6 +72,7 @@ DEFAULT_LINE_LENGTH = 88
 DEFAULT_EXCLUDES = r"/(\.direnv|\.eggs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|\.svn|_build|buck-out|build|dist)/"  # noqa: B950
 DEFAULT_INCLUDES = r"\.pyi?$"
 CACHE_DIR = Path(user_cache_dir("black", version=__version__))
 DEFAULT_EXCLUDES = r"/(\.direnv|\.eggs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|\.svn|_build|buck-out|build|dist)/"  # noqa: B950
 DEFAULT_INCLUDES = r"\.pyi?$"
 CACHE_DIR = Path(user_cache_dir("black", version=__version__))

+STDIN_PLACEHOLDER = "__BLACK_STDIN_FILENAME__"

 
 STRING_PREFIX_CHARS: Final = "furbFURB"  # All possible string prefix characters.
 
 
 STRING_PREFIX_CHARS: Final = "furbFURB"  # All possible string prefix characters.
 


@@ -88,7 +93,7 @@ Transformer = Callable[["Line", Collection["Feature"]], Iterator["Line"]]
 Timestamp = float
 FileSize = int
 CacheInfo = Tuple[Timestamp, FileSize]
 Timestamp = float
 FileSize = int
 CacheInfo = Tuple[Timestamp, FileSize]

-Cache = Dict[Path, CacheInfo]
+Cache = Dict[str, CacheInfo]

 out = partial(click.secho, bold=True, err=True)
 err = partial(click.secho, fg="red", err=True)
 
 out = partial(click.secho, bold=True, err=True)
 err = partial(click.secho, fg="red", err=True)
 


@@ -255,6 +260,7 @@ class Mode:
     target_versions: Set[TargetVersion] = field(default_factory=set)
     line_length: int = DEFAULT_LINE_LENGTH
     string_normalization: bool = True
     target_versions: Set[TargetVersion] = field(default_factory=set)
     line_length: int = DEFAULT_LINE_LENGTH
     string_normalization: bool = True

+    magic_trailing_comma: bool = True

     experimental_string_processing: bool = False
     is_pyi: bool = False
 
     experimental_string_processing: bool = False
     is_pyi: bool = False
 


@@ -392,6 +398,12 @@ def target_version_option_callback(
     is_flag=True,
     help="Don't normalize string quotes or prefixes.",
 )
     is_flag=True,
     help="Don't normalize string quotes or prefixes.",
 )

+@click.option(
+    "-C",
+    "--skip-magic-trailing-comma",
+    is_flag=True,
+    help="Don't use trailing commas as a reason to split lines.",
+)

 @click.option(
     "--experimental-string-processing",
     is_flag=True,
 @click.option(
     "--experimental-string-processing",
     is_flag=True,


@@ -457,6 +469,15 @@ def target_version_option_callback(
         "excluded even when they are passed explicitly as arguments."
     ),
 )
         "excluded even when they are passed explicitly as arguments."
     ),
 )

+@click.option(
+    "--stdin-filename",
+    type=str,
+    help=(
+        "The name of the file when passing it through stdin. Useful to make "
+        "sure Black will respect --force-exclude option on some "
+        "editors that rely on using stdin."
+    ),
+)

 @click.option(
     "-q",
     "--quiet",
 @click.option(
     "-q",
     "--quiet",


@@ -510,12 +531,14 @@ def main(
     fast: bool,
     pyi: bool,
     skip_string_normalization: bool,
     fast: bool,
     pyi: bool,
     skip_string_normalization: bool,

+    skip_magic_trailing_comma: bool,

     experimental_string_processing: bool,
     quiet: bool,
     verbose: bool,
     include: str,
     exclude: str,
     force_exclude: Optional[str],
     experimental_string_processing: bool,
     quiet: bool,
     verbose: bool,
     include: str,
     exclude: str,
     force_exclude: Optional[str],

+    stdin_filename: Optional[str],

     src: Tuple[str, ...],
     config: Optional[str],
 ) -> None:
     src: Tuple[str, ...],
     config: Optional[str],
 ) -> None:


@@ -531,6 +554,7 @@ def main(
         line_length=line_length,
         is_pyi=pyi,
         string_normalization=not skip_string_normalization,
         line_length=line_length,
         is_pyi=pyi,
         string_normalization=not skip_string_normalization,

+        magic_trailing_comma=not skip_magic_trailing_comma,

         experimental_string_processing=experimental_string_processing,
     )
     if config and verbose:
         experimental_string_processing=experimental_string_processing,
     )
     if config and verbose:


@@ -548,6 +572,7 @@ def main(
         exclude=exclude,
         force_exclude=force_exclude,
         report=report,
         exclude=exclude,
         force_exclude=force_exclude,
         report=report,

+        stdin_filename=stdin_filename,

     )
 
     path_empty(
     )
 
     path_empty(


@@ -587,6 +612,7 @@ def get_sources(
     exclude: str,
     force_exclude: Optional[str],
     report: "Report",
     exclude: str,
     force_exclude: Optional[str],
     report: "Report",

+    stdin_filename: Optional[str],

 ) -> Set[Path]:
     """Compute the set of files to be formatted."""
     try:
 ) -> Set[Path]:
     """Compute the set of files to be formatted."""
     try:


@@ -613,22 +639,14 @@ def get_sources(
     gitignore = get_gitignore(root)
 
     for s in src:
     gitignore = get_gitignore(root)
 
     for s in src:

-        p = Path(s)
-        if p.is_dir():
-            sources.update(
-                gen_python_files(
-                    p.iterdir(),
-                    root,
-                    include_regex,
-                    exclude_regex,
-                    force_exclude_regex,
-                    report,
-                    gitignore,
-                )
-            )
-        elif s == "-":
-            sources.add(p)
-        elif p.is_file():
+        if s == "-" and stdin_filename:
+            p = Path(stdin_filename)
+            is_stdin = True
+        else:
+            p = Path(s)
+            is_stdin = False
+
+        if is_stdin or p.is_file():

             normalized_path = normalize_path_maybe_ignore(p, root, report)
             if normalized_path is None:
                 continue
             normalized_path = normalize_path_maybe_ignore(p, root, report)
             if normalized_path is None:
                 continue


@@ -643,6 +661,23 @@ def get_sources(
                 report.path_ignored(p, "matches the --force-exclude regular expression")
                 continue
 
                 report.path_ignored(p, "matches the --force-exclude regular expression")
                 continue
 

+            if is_stdin:
+                p = Path(f"{STDIN_PLACEHOLDER}{str(p)}")
+
+            sources.add(p)
+        elif p.is_dir():
+            sources.update(
+                gen_python_files(
+                    p.iterdir(),
+                    root,
+                    include_regex,
+                    exclude_regex,
+                    force_exclude_regex,
+                    report,
+                    gitignore,
+                )
+            )
+        elif s == "-":

             sources.add(p)
         else:
             err(f"invalid path: {s}")
             sources.add(p)
         else:
             err(f"invalid path: {s}")


@@ -670,7 +705,18 @@ def reformat_one(
     """
     try:
         changed = Changed.NO
     """
     try:
         changed = Changed.NO

-        if not src.is_file() and str(src) == "-":
+
+        if str(src) == "-":
+            is_stdin = True
+        elif str(src).startswith(STDIN_PLACEHOLDER):
+            is_stdin = True
+            # Use the original name again in case we want to print something
+            # to the user
+            src = Path(str(src)[len(STDIN_PLACEHOLDER) :])
+        else:
+            is_stdin = False
+
+        if is_stdin:

             if format_stdin_to_stdout(fast=fast, write_back=write_back, mode=mode):
                 changed = Changed.YES
         else:
             if format_stdin_to_stdout(fast=fast, write_back=write_back, mode=mode):
                 changed = Changed.YES
         else:


@@ -678,7 +724,8 @@ def reformat_one(
             if write_back not in (WriteBack.DIFF, WriteBack.COLOR_DIFF):
                 cache = read_cache(mode)
                 res_src = src.resolve()
             if write_back not in (WriteBack.DIFF, WriteBack.COLOR_DIFF):
                 cache = read_cache(mode)
                 res_src = src.resolve()

-                if res_src in cache and cache[res_src] == get_cache_info(res_src):
+                res_src_s = str(res_src)
+                if res_src_s in cache and cache[res_src_s] == get_cache_info(res_src):

                     changed = Changed.CACHED
             if changed is not Changed.CACHED and format_file_in_place(
                 src, fast=fast, write_back=write_back, mode=mode
                     changed = Changed.CACHED
             if changed is not Changed.CACHED and format_file_in_place(
                 src, fast=fast, write_back=write_back, mode=mode


@@ -704,7 +751,7 @@ def reformat_many(
     worker_count = os.cpu_count()
     if sys.platform == "win32":
         # Work around https://bugs.python.org/issue26903
     worker_count = os.cpu_count()
     if sys.platform == "win32":
         # Work around https://bugs.python.org/issue26903

-        worker_count = min(worker_count, 61)
+        worker_count = min(worker_count, 60)

     try:
         executor = ProcessPoolExecutor(max_workers=worker_count)
     except (ImportError, OSError):
     try:
         executor = ProcessPoolExecutor(max_workers=worker_count)
     except (ImportError, OSError):


@@ -953,7 +1000,7 @@ def format_str(src_contents: str, *, mode: Mode) -> FileContent:
     allowed.  Example:
 
     >>> import black
     allowed.  Example:
 
     >>> import black

-    >>> print(black.format_str("def f(arg:str='')->None:...", mode=Mode()))
+    >>> print(black.format_str("def f(arg:str='')->None:...", mode=black.Mode()))

     def f(arg: str = "") -> None:
         ...
 
     def f(arg: str = "") -> None:
         ...
 


@@ -985,13 +1032,12 @@ def format_str(src_contents: str, *, mode: Mode) -> FileContent:
         versions = detect_target_versions(src_node)
     normalize_fmt_off(src_node)
     lines = LineGenerator(
         versions = detect_target_versions(src_node)
     normalize_fmt_off(src_node)
     lines = LineGenerator(

+        mode=mode,

         remove_u_prefix="unicode_literals" in future_imports
         or supports_feature(versions, Feature.UNICODE_LITERALS),
         remove_u_prefix="unicode_literals" in future_imports
         or supports_feature(versions, Feature.UNICODE_LITERALS),

-        is_pyi=mode.is_pyi,
-        normalize_strings=mode.string_normalization,

     )
     elt = EmptyLineTracker(is_pyi=mode.is_pyi)
     )
     elt = EmptyLineTracker(is_pyi=mode.is_pyi)

-    empty_line = Line()
+    empty_line = Line(mode=mode)

     after = 0
     split_line_features = {
         feature
     after = 0
     split_line_features = {
         feature


@@ -1427,6 +1473,7 @@ class BracketTracker:
 class Line:
     """Holds leaves and comments. Can be printed with `str(line)`."""
 
 class Line:
     """Holds leaves and comments. Can be printed with `str(line)`."""
 

+    mode: Mode

     depth: int = 0
     leaves: List[Leaf] = field(default_factory=list)
     # keys ordered like `leaves`
     depth: int = 0
     leaves: List[Leaf] = field(default_factory=list)
     # keys ordered like `leaves`


@@ -1459,8 +1506,11 @@ class Line:
             )
         if self.inside_brackets or not preformatted:
             self.bracket_tracker.mark(leaf)
             )
         if self.inside_brackets or not preformatted:
             self.bracket_tracker.mark(leaf)

-            if self.maybe_should_explode(leaf):
-                self.should_explode = True
+            if self.mode.magic_trailing_comma:
+                if self.has_magic_trailing_comma(leaf):
+                    self.should_explode = True
+            elif self.has_magic_trailing_comma(leaf, ensure_removable=True):
+                self.remove_trailing_comma()

         if not self.append_comment(leaf):
             self.leaves.append(leaf)
 
         if not self.append_comment(leaf):
             self.leaves.append(leaf)
 


@@ -1636,10 +1686,14 @@ class Line:
     def contains_multiline_strings(self) -> bool:
         return any(is_multiline_string(leaf) for leaf in self.leaves)
 
     def contains_multiline_strings(self) -> bool:
         return any(is_multiline_string(leaf) for leaf in self.leaves)
 

-    def maybe_should_explode(self, closing: Leaf) -> bool:
-        """Return True if this line should explode (always be split), that is when:
-        - there's a trailing comma here; and
-        - it's not a one-tuple.
+    def has_magic_trailing_comma(
+        self, closing: Leaf, ensure_removable: bool = False
+    ) -> bool:
+        """Return True if we have a magic trailing comma, that is when:
+        - there's a trailing comma here
+        - it's not a one-tuple
+        Additionally, if ensure_removable:
+        - it's not from square bracket indexing

         """
         if not (
             closing.type in CLOSING_BRACKETS
         """
         if not (
             closing.type in CLOSING_BRACKETS


@@ -1648,9 +1702,15 @@ class Line:
         ):
             return False
 
         ):
             return False
 

-        if closing.type in {token.RBRACE, token.RSQB}:
+        if closing.type == token.RBRACE:

             return True
 
             return True
 

+        if closing.type == token.RSQB:
+            if not ensure_removable:
+                return True
+            comma = self.leaves[-1]
+            return bool(comma.parent and comma.parent.type == syms.listmaker)
+

         if self.is_import:
             return True
 
         if self.is_import:
             return True
 


@@ -1728,6 +1788,7 @@ class Line:
 
     def clone(self) -> "Line":
         return Line(
 
     def clone(self) -> "Line":
         return Line(

+            mode=self.mode,

             depth=self.depth,
             inside_brackets=self.inside_brackets,
             should_explode=self.should_explode,
             depth=self.depth,
             inside_brackets=self.inside_brackets,
             should_explode=self.should_explode,


@@ -1886,10 +1947,9 @@ class LineGenerator(Visitor[Line]):
     in ways that will no longer stringify to valid Python code on the tree.
     """
 
     in ways that will no longer stringify to valid Python code on the tree.
     """
 

-    is_pyi: bool = False
-    normalize_strings: bool = True
-    current_line: Line = field(default_factory=Line)
+    mode: Mode

     remove_u_prefix: bool = False
     remove_u_prefix: bool = False

+    current_line: Line = field(init=False)

 
     def line(self, indent: int = 0) -> Iterator[Line]:
         """Generate a line.
 
     def line(self, indent: int = 0) -> Iterator[Line]:
         """Generate a line.


@@ -1904,7 +1964,7 @@ class LineGenerator(Visitor[Line]):
             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 = Line(depth=complete_line.depth + indent)
+        self.current_line = Line(mode=self.mode, depth=complete_line.depth + indent)

         yield complete_line
 
     def visit_default(self, node: LN) -> Iterator[Line]:
         yield complete_line
 
     def visit_default(self, node: LN) -> Iterator[Line]:


@@ -1928,7 +1988,7 @@ class LineGenerator(Visitor[Line]):
                     yield from self.line()
 
             normalize_prefix(node, inside_brackets=any_open_brackets)
                     yield from self.line()
 
             normalize_prefix(node, inside_brackets=any_open_brackets)

-            if self.normalize_strings and node.type == token.STRING:
+            if self.mode.string_normalization 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_string_prefix(node, remove_u_prefix=self.remove_u_prefix)
                 normalize_string_quotes(node)
             if node.type == token.NUMBER:


@@ -1980,7 +2040,7 @@ class LineGenerator(Visitor[Line]):
 
     def visit_suite(self, node: Node) -> Iterator[Line]:
         """Visit a suite."""
 
     def visit_suite(self, node: Node) -> Iterator[Line]:
         """Visit a suite."""

-        if self.is_pyi and is_stub_suite(node):
+        if self.mode.is_pyi and is_stub_suite(node):

             yield from self.visit(node.children[2])
         else:
             yield from self.visit_default(node)
             yield from self.visit(node.children[2])
         else:
             yield from self.visit_default(node)


@@ -1989,7 +2049,7 @@ class LineGenerator(Visitor[Line]):
         """Visit a statement without nested statements."""
         is_suite_like = node.parent and node.parent.type in STATEMENT
         if is_suite_like:
         """Visit a statement without nested statements."""
         is_suite_like = node.parent and node.parent.type in STATEMENT
         if is_suite_like:

-            if self.is_pyi and is_stub_body(node):
+            if self.mode.is_pyi and is_stub_body(node):

                 yield from self.visit_default(node)
             else:
                 yield from self.line(+1)
                 yield from self.visit_default(node)
             else:
                 yield from self.line(+1)


@@ -1997,7 +2057,11 @@ class LineGenerator(Visitor[Line]):
                 yield from self.line(-1)
 
         else:
                 yield from self.line(-1)
 
         else:

-            if not self.is_pyi or not node.parent or not is_stub_suite(node.parent):
+            if (
+                not self.mode.is_pyi
+                or not node.parent
+                or not is_stub_suite(node.parent)
+            ):

                 yield from self.line()
             yield from self.visit_default(node)
 
                 yield from self.line()
             yield from self.visit_default(node)
 


@@ -2073,6 +2137,8 @@ class LineGenerator(Visitor[Line]):
 
     def __post_init__(self) -> None:
         """You are in a twisty little maze of passages."""
 
     def __post_init__(self) -> None:
         """You are in a twisty little maze of passages."""

+        self.current_line = Line(mode=self.mode)
+

         v = self.visit_stmt
         Ø: Set[str] = set()
         self.visit_assert_stmt = partial(v, keywords={"assert"}, parens={"assert", ","})
         v = self.visit_stmt
         Ø: Set[str] = set()
         self.visit_assert_stmt = partial(v, keywords={"assert"}, parens={"assert", ","})


@@ -2569,7 +2635,7 @@ def list_comments(prefix: str, *, is_endmarker: bool) -> List[ProtoComment]:
     consumed = 0
     nlines = 0
     ignored_lines = 0
     consumed = 0
     nlines = 0
     ignored_lines = 0

-    for index, line in enumerate(prefix.split("\n")):
+    for index, line in enumerate(re.split("\r?\n", prefix)):

         consumed += len(line) + 1  # adding the length of the split '\n'
         line = line.lstrip()
         if not line:
         consumed += len(line) + 1  # adding the length of the split '\n'
         line = line.lstrip()
         if not line:


@@ -3238,7 +3304,8 @@ class StringParenStripper(StringTransformer):
 
     Requirements:
         The line contains a string which is surrounded by parentheses and:
 
     Requirements:
         The line contains a string which is surrounded by parentheses and:

-            - The target string is NOT the only argument to a function call).
+            - The target string is NOT the only argument to a function call.
+            - The target string is NOT a "pointless" string.

             - If the target string contains a PERCENT, the brackets are not
               preceeded or followed by an operator with higher precedence than
               PERCENT.
             - If the target string contains a PERCENT, the brackets are not
               preceeded or followed by an operator with higher precedence than
               PERCENT.


@@ -3262,6 +3329,14 @@ class StringParenStripper(StringTransformer):
             if leaf.type != token.STRING:
                 continue
 
             if leaf.type != token.STRING:
                 continue
 

+            # If this is a "pointless" string...
+            if (
+                leaf.parent
+                and leaf.parent.parent
+                and leaf.parent.parent.type == syms.simple_stmt
+            ):
+                continue
+

             # Should be preceded by a non-empty LPAR...
             if (
                 not is_valid_index(idx - 1)
             # Should be preceded by a non-empty LPAR...
             if (
                 not is_valid_index(idx - 1)


@@ -3611,13 +3686,14 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter):
     MIN_SUBSTR_SIZE = 6
     # Matches an "f-expression" (e.g. {var}) that might be found in an f-string.
     RE_FEXPR = r"""
     MIN_SUBSTR_SIZE = 6
     # Matches an "f-expression" (e.g. {var}) that might be found in an f-string.
     RE_FEXPR = r"""

-    (?<!\{)\{
+    (?<!\{) (?:\{\{)* \{ (?!\{)

         (?:
             [^\{\}]
             | \{\{
             | \}\}
         (?:
             [^\{\}]
             | \{\{
             | \}\}

+            | (?R)

         )+?
         )+?

-    (?<!\})(?:\}\})*\}(?!\})
+    (?<!\}) \} (?:\}\})* (?!\})

     """
 
     def do_splitter_match(self, line: Line) -> TMatchResult:
     """
 
     def do_splitter_match(self, line: Line) -> TMatchResult:


@@ -4303,6 +4379,7 @@ class StringParenWrapper(CustomSplitMapMixin, BaseStringSplitter):
         # `StringSplitter` will break it down further if necessary.
         string_value = LL[string_idx].value
         string_line = Line(
         # `StringSplitter` will break it down further if necessary.
         string_value = LL[string_idx].value
         string_line = Line(

+            mode=line.mode,

             depth=line.depth + 1,
             inside_brackets=True,
             should_explode=line.should_explode,
             depth=line.depth + 1,
             inside_brackets=True,
             should_explode=line.should_explode,


@@ -4896,7 +4973,7 @@ def bracket_split_build_line(
     If `is_body` is True, the result line is one-indented inside brackets and as such
     has its first leaf's prefix normalized and a trailing comma added when expected.
     """
     If `is_body` is True, the result line is one-indented inside brackets and as such
     has its first leaf's prefix normalized and a trailing comma added when expected.
     """

-    result = Line(depth=original.depth)
+    result = Line(mode=original.mode, depth=original.depth)

     if is_body:
         result.inside_brackets = True
         result.depth += 1
     if is_body:
         result.inside_brackets = True
         result.depth += 1


@@ -4968,7 +5045,9 @@ def delimiter_split(line: Line, features: Collection[Feature] = ()) -> Iterator[
         if bt.delimiter_count_with_priority(delimiter_priority) == 1:
             raise CannotSplit("Splitting a single attribute from its owner looks wrong")
 
         if bt.delimiter_count_with_priority(delimiter_priority) == 1:
             raise CannotSplit("Splitting a single attribute from its owner looks wrong")
 

-    current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)
+    current_line = Line(
+        mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+    )

     lowest_depth = sys.maxsize
     trailing_comma_safe = True
 
     lowest_depth = sys.maxsize
     trailing_comma_safe = True
 


@@ -4980,7 +5059,9 @@ def delimiter_split(line: Line, features: Collection[Feature] = ()) -> Iterator[
         except ValueError:
             yield current_line
 
         except ValueError:
             yield current_line
 

-            current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)
+            current_line = Line(
+                mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+            )

             current_line.append(leaf)
 
     for leaf in line.leaves:
             current_line.append(leaf)
 
     for leaf in line.leaves:


@@ -5004,7 +5085,9 @@ def delimiter_split(line: Line, features: Collection[Feature] = ()) -> Iterator[
         if leaf_priority == delimiter_priority:
             yield current_line
 
         if leaf_priority == delimiter_priority:
             yield current_line
 

-            current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)
+            current_line = Line(
+                mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+            )

     if current_line:
         if (
             trailing_comma_safe
     if current_line:
         if (
             trailing_comma_safe


@@ -5025,7 +5108,9 @@ def standalone_comment_split(
     if not line.contains_standalone_comments(0):
         raise CannotSplit("Line does not have any standalone comments")
 
     if not line.contains_standalone_comments(0):
         raise CannotSplit("Line does not have any standalone comments")
 

-    current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)
+    current_line = Line(
+        mode=line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+    )

 
     def append_to_line(leaf: Leaf) -> Iterator[Line]:
         """Append `leaf` to current line or to new line if appending impossible."""
 
     def append_to_line(leaf: Leaf) -> Iterator[Line]:
         """Append `leaf` to current line or to new line if appending impossible."""


@@ -5035,7 +5120,9 @@ def standalone_comment_split(
         except ValueError:
             yield current_line
 
         except ValueError:
             yield current_line
 

-            current_line = Line(depth=line.depth, inside_brackets=line.inside_brackets)
+            current_line = Line(
+                line.mode, depth=line.depth, inside_brackets=line.inside_brackets
+            )

             current_line.append(leaf)
 
     for leaf in line.leaves:
             current_line.append(leaf)
 
     for leaf in line.leaves:


@@ -5191,31 +5278,52 @@ def normalize_numeric_literal(leaf: Leaf) -> None:
         # Leave octal and binary literals alone.
         pass
     elif text.startswith("0x"):
         # Leave octal and binary literals alone.
         pass
     elif text.startswith("0x"):

-        # Change hex literals to upper case.
-        before, after = text[:2], text[2:]
-        text = f"{before}{after.upper()}"
+        text = format_hex(text)

     elif "e" in text:
     elif "e" in text:

-        before, after = text.split("e")
-        sign = ""
-        if after.startswith("-"):
-            after = after[1:]
-            sign = "-"
-        elif after.startswith("+"):
-            after = after[1:]
-        before = format_float_or_int_string(before)
-        text = f"{before}e{sign}{after}"
+        text = format_scientific_notation(text)

     elif text.endswith(("j", "l")):
     elif text.endswith(("j", "l")):

-        number = text[:-1]
-        suffix = text[-1]
-        # Capitalize in "2L" because "l" looks too similar to "1".
-        if suffix == "l":
-            suffix = "L"
-        text = f"{format_float_or_int_string(number)}{suffix}"
+        text = format_long_or_complex_number(text)

     else:
         text = format_float_or_int_string(text)
     leaf.value = text
 
 
     else:
         text = format_float_or_int_string(text)
     leaf.value = text
 
 

+def format_hex(text: str) -> str:
+    """
+    Formats a hexadecimal string like "0x12b3"
+
+    Uses lowercase because of similarity between "B" and "8", which
+    can cause security issues.
+    see: https://github.com/psf/black/issues/1692
+    """
+
+    before, after = text[:2], text[2:]
+    return f"{before}{after.lower()}"
+
+
+def format_scientific_notation(text: str) -> str:
+    """Formats a numeric string utilizing scentific notation"""
+    before, after = text.split("e")
+    sign = ""
+    if after.startswith("-"):
+        after = after[1:]
+        sign = "-"
+    elif after.startswith("+"):
+        after = after[1:]
+    before = format_float_or_int_string(before)
+    return f"{before}e{sign}{after}"
+
+
+def format_long_or_complex_number(text: str) -> str:
+    """Formats a long or complex string like `10L` or `10j`"""
+    number = text[:-1]
+    suffix = text[-1]
+    # Capitalize in "2L" because "l" looks too similar to "1".
+    if suffix == "l":
+        suffix = "L"
+    return f"{format_float_or_int_string(number)}{suffix}"
+
+

 def format_float_or_int_string(text: str) -> str:
     """Formats a float string like "1.0"."""
     if "." not in text:
 def format_float_or_int_string(text: str) -> str:
     """Formats a float string like "1.0"."""
     if "." not in text:


@@ -5699,7 +5807,7 @@ def should_split_body_explode(line: Line, opening_bracket: Leaf) -> bool:
         return False
 
     return max_priority == COMMA_PRIORITY and (
         return False
 
     return max_priority == COMMA_PRIORITY and (

-        trailing_comma
+        (line.mode.magic_trailing_comma and trailing_comma)

         # always explode imports
         or opening_bracket.parent.type in {syms.atom, syms.import_from}
     )
         # always explode imports
         or opening_bracket.parent.type in {syms.atom, syms.import_from}
     )


@@ -6674,8 +6782,8 @@ def filter_cached(cache: Cache, sources: Iterable[Path]) -> Tuple[Set[Path], Set
     """
     todo, done = set(), set()
     for src in sources:
     """
     todo, done = set(), set()
     for src in sources:

-        src = src.resolve()
-        if cache.get(src) != get_cache_info(src):
+        res_src = src.resolve()
+        if cache.get(str(res_src)) != get_cache_info(res_src):

             todo.add(src)
         else:
             done.add(src)
             todo.add(src)
         else:
             done.add(src)


@@ -6687,7 +6795,10 @@ def write_cache(cache: Cache, sources: Iterable[Path], mode: Mode) -> None:
     cache_file = get_cache_file(mode)
     try:
         CACHE_DIR.mkdir(parents=True, exist_ok=True)
     cache_file = get_cache_file(mode)
     try:
         CACHE_DIR.mkdir(parents=True, exist_ok=True)

-        new_cache = {**cache, **{src.resolve(): get_cache_info(src) for src in sources}}
+        new_cache = {
+            **cache,
+            **{str(src.resolve()): get_cache_info(src) for src in sources},
+        }

         with tempfile.NamedTemporaryFile(dir=str(cache_file.parent), delete=False) as f:
             pickle.dump(new_cache, f, protocol=4)
         os.replace(f.name, cache_file)
         with tempfile.NamedTemporaryFile(dir=str(cache_file.parent), delete=False) as f:
             pickle.dump(new_cache, f, protocol=4)
         os.replace(f.name, cache_file)


@@ -6743,13 +6854,33 @@ def is_docstring(leaf: Leaf) -> bool:
     return False
 
 
     return False
 
 

+def lines_with_leading_tabs_expanded(s: str) -> List[str]:
+    """
+    Splits string into lines and expands only leading tabs (following the normal
+    Python rules)
+    """
+    lines = []
+    for line in s.splitlines():
+        # Find the index of the first non-whitespace character after a string of
+        # whitespace that includes at least one tab
+        match = re.match(r"\s*\t+\s*(\S)", line)
+        if match:
+            first_non_whitespace_idx = match.start(1)
+
+            lines.append(
+                line[:first_non_whitespace_idx].expandtabs()
+                + line[first_non_whitespace_idx:]
+            )
+        else:
+            lines.append(line)
+    return lines
+
+

 def fix_docstring(docstring: str, prefix: str) -> str:
     # https://www.python.org/dev/peps/pep-0257/#handling-docstring-indentation
     if not docstring:
         return ""
 def fix_docstring(docstring: str, prefix: str) -> str:
     # https://www.python.org/dev/peps/pep-0257/#handling-docstring-indentation
     if not docstring:
         return ""

-    # Convert tabs to spaces (following the normal Python rules)
-    # and split into a list of lines:
-    lines = docstring.expandtabs().splitlines()
+    lines = lines_with_leading_tabs_expanded(docstring)

     # Determine minimum indentation (first line doesn't count):
     indent = sys.maxsize
     for line in lines[1:]:
     # Determine minimum indentation (first line doesn't count):
     indent = sys.maxsize
     for line in lines[1:]: