traceback.py

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from __future__ import absolute_import
 
import linecache
import os
import platform
import sys
from dataclasses import dataclass, field
from traceback import walk_tb
from types import ModuleType, TracebackType
from typing import (
    Any,
    Callable,
    Dict,
    Iterable,
    List,
    Optional,
    Sequence,
    Tuple,
    Type,
    Union,
)
 
from pip._vendor.pygments.lexers import guess_lexer_for_filename
from pip._vendor.pygments.token import Comment, Keyword, Name, Number, Operator, String
from pip._vendor.pygments.token import Text as TextToken
from pip._vendor.pygments.token import Token
from pip._vendor.pygments.util import ClassNotFound
 
from . import pretty
from ._loop import loop_last
from .columns import Columns
from .console import Console, ConsoleOptions, ConsoleRenderable, RenderResult, group
from .constrain import Constrain
from .highlighter import RegexHighlighter, ReprHighlighter
from .panel import Panel
from .scope import render_scope
from .style import Style
from .syntax import Syntax
from .text import Text
from .theme import Theme
 
WINDOWS = platform.system() == "Windows"
 
LOCALS_MAX_LENGTH = 10
LOCALS_MAX_STRING = 80
 
 
def install(
    *,
    console: Optional[Console] = None,
    width: Optional[int] = 100,
    extra_lines: int = 3,
    theme: Optional[str] = None,
    word_wrap: bool = False,
    show_locals: bool = False,
    locals_max_length: int = LOCALS_MAX_LENGTH,
    locals_max_string: int = LOCALS_MAX_STRING,
    locals_hide_dunder: bool = True,
    locals_hide_sunder: Optional[bool] = None,
    indent_guides: bool = True,
    suppress: Iterable[Union[str, ModuleType]] = (),
    max_frames: int = 100,
) -> Callable[[Type[BaseException], BaseException, Optional[TracebackType]], Any]:
    """Install a rich traceback handler.
 
    Once installed, any tracebacks will be printed with syntax highlighting and rich formatting.
 
 
    Args:
        console (Optional[Console], optional): Console to write exception to. Default uses internal Console instance.
        width (Optional[int], optional): Width (in characters) of traceback. Defaults to 100.
        extra_lines (int, optional): Extra lines of code. Defaults to 3.
        theme (Optional[str], optional): Pygments theme to use in traceback. Defaults to ``None`` which will pick
            a theme appropriate for the platform.
        word_wrap (bool, optional): Enable word wrapping of long lines. Defaults to False.
        show_locals (bool, optional): Enable display of local variables. Defaults to False.
        locals_max_length (int, optional): Maximum length of containers before abbreviating, or None for no abbreviation.
            Defaults to 10.
        locals_max_string (int, optional): Maximum length of string before truncating, or None to disable. Defaults to 80.
        locals_hide_dunder (bool, optional): Hide locals prefixed with double underscore. Defaults to True.
        locals_hide_sunder (bool, optional): Hide locals prefixed with single underscore. Defaults to False.
        indent_guides (bool, optional): Enable indent guides in code and locals. Defaults to True.
        suppress (Sequence[Union[str, ModuleType]]): Optional sequence of modules or paths to exclude from traceback.
 
    Returns:
        Callable: The previous exception handler that was replaced.
 
    """
    traceback_console = Console(stderr=True) if console is None else console
 
    locals_hide_sunder = (
        True
        if (traceback_console.is_jupyter and locals_hide_sunder is None)
        else locals_hide_sunder
    )
 
    def excepthook(
        type_: Type[BaseException],
        value: BaseException,
        traceback: Optional[TracebackType],
    ) -> None:
        traceback_console.print(
            Traceback.from_exception(
                type_,
                value,
                traceback,
                width=width,
                extra_lines=extra_lines,
                theme=theme,
                word_wrap=word_wrap,
                show_locals=show_locals,
                locals_max_length=locals_max_length,
                locals_max_string=locals_max_string,
                locals_hide_dunder=locals_hide_dunder,
                locals_hide_sunder=bool(locals_hide_sunder),
                indent_guides=indent_guides,
                suppress=suppress,
                max_frames=max_frames,
            )
        )
 
    def ipy_excepthook_closure(ip: Any) -> None:  # pragma: no cover
        tb_data = {}  # store information about showtraceback call
        default_showtraceback = ip.showtraceback  # keep reference of default traceback
 
        def ipy_show_traceback(*args: Any, **kwargs: Any) -> None:
            """wrap the default ip.showtraceback to store info for ip._showtraceback"""
            nonlocal tb_data
            tb_data = kwargs
            default_showtraceback(*args, **kwargs)
 
        def ipy_display_traceback(
            *args: Any, is_syntax: bool = False, **kwargs: Any
        ) -> None:
            """Internally called traceback from ip._showtraceback"""
            nonlocal tb_data
            exc_tuple = ip._get_exc_info()
 
            # do not display trace on syntax error
            tb: Optional[TracebackType] = None if is_syntax else exc_tuple[2]
 
            # determine correct tb_offset
            compiled = tb_data.get("running_compiled_code", False)
            tb_offset = tb_data.get("tb_offset", 1 if compiled else 0)
            # remove ipython internal frames from trace with tb_offset
            for _ in range(tb_offset):
                if tb is None:
                    break
                tb = tb.tb_next
 
            excepthook(exc_tuple[0], exc_tuple[1], tb)
            tb_data = {}  # clear data upon usage
 
        # replace _showtraceback instead of showtraceback to allow ipython features such as debugging to work
        # this is also what the ipython docs recommends to modify when subclassing InteractiveShell
        ip._showtraceback = ipy_display_traceback
        # add wrapper to capture tb_data
        ip.showtraceback = ipy_show_traceback
        ip.showsyntaxerror = lambda *args, **kwargs: ipy_display_traceback(
            *args, is_syntax=True, **kwargs
        )
 
    try:  # pragma: no cover
        # if within ipython, use customized traceback
        ip = get_ipython()  # type: ignore[name-defined]
        ipy_excepthook_closure(ip)
        return sys.excepthook
    except Exception:
        # otherwise use default system hook
        old_excepthook = sys.excepthook
        sys.excepthook = excepthook
        return old_excepthook
 
 
@dataclass
class Frame:
    filename: str
    lineno: int
    name: str
    line: str = ""
    locals: Optional[Dict[str, pretty.Node]] = None
 
 
@dataclass
class _SyntaxError:
    offset: int
    filename: str
    line: str
    lineno: int
    msg: str
 
 
@dataclass
class Stack:
    exc_type: str
    exc_value: str
    syntax_error: Optional[_SyntaxError] = None
    is_cause: bool = False
    frames: List[Frame] = field(default_factory=list)
 
 
@dataclass
class Trace:
    stacks: List[Stack]
 
 
class PathHighlighter(RegexHighlighter):
    highlights = [r"(?P<dim>.*/)(?P<bold>.+)"]
 
 
class Traceback:
    """A Console renderable that renders a traceback.
 
    Args:
        trace (Trace, optional): A `Trace` object produced from `extract`. Defaults to None, which uses
            the last exception.
        width (Optional[int], optional): Number of characters used to traceback. Defaults to 100.
        extra_lines (int, optional): Additional lines of code to render. Defaults to 3.
        theme (str, optional): Override pygments theme used in traceback.
        word_wrap (bool, optional): Enable word wrapping of long lines. Defaults to False.
        show_locals (bool, optional): Enable display of local variables. Defaults to False.
        indent_guides (bool, optional): Enable indent guides in code and locals. Defaults to True.
        locals_max_length (int, optional): Maximum length of containers before abbreviating, or None for no abbreviation.
            Defaults to 10.
        locals_max_string (int, optional): Maximum length of string before truncating, or None to disable. Defaults to 80.
        locals_hide_dunder (bool, optional): Hide locals prefixed with double underscore. Defaults to True.
        locals_hide_sunder (bool, optional): Hide locals prefixed with single underscore. Defaults to False.
        suppress (Sequence[Union[str, ModuleType]]): Optional sequence of modules or paths to exclude from traceback.
        max_frames (int): Maximum number of frames to show in a traceback, 0 for no maximum. Defaults to 100.
 
    """
 
    LEXERS = {
        "": "text",
        ".py": "python",
        ".pxd": "cython",
        ".pyx": "cython",
        ".pxi": "pyrex",
    }
 
    def __init__(
        self,
        trace: Optional[Trace] = None,
        *,
        width: Optional[int] = 100,
        extra_lines: int = 3,
        theme: Optional[str] = None,
        word_wrap: bool = False,
        show_locals: bool = False,
        locals_max_length: int = LOCALS_MAX_LENGTH,
        locals_max_string: int = LOCALS_MAX_STRING,
        locals_hide_dunder: bool = True,
        locals_hide_sunder: bool = False,
        indent_guides: bool = True,
        suppress: Iterable[Union[str, ModuleType]] = (),
        max_frames: int = 100,
    ):
        if trace is None:
            exc_type, exc_value, traceback = sys.exc_info()
            if exc_type is None or exc_value is None or traceback is None:
                raise ValueError(
                    "Value for 'trace' required if not called in except: block"
                )
            trace = self.extract(
                exc_type, exc_value, traceback, show_locals=show_locals
            )
        self.trace = trace
        self.width = width
        self.extra_lines = extra_lines
        self.theme = Syntax.get_theme(theme or "ansi_dark")
        self.word_wrap = word_wrap
        self.show_locals = show_locals
        self.indent_guides = indent_guides
        self.locals_max_length = locals_max_length
        self.locals_max_string = locals_max_string
        self.locals_hide_dunder = locals_hide_dunder
        self.locals_hide_sunder = locals_hide_sunder
 
        self.suppress: Sequence[str] = []
        for suppress_entity in suppress:
            if not isinstance(suppress_entity, str):
                assert (
                    suppress_entity.__file__ is not None
                ), f"{suppress_entity!r} must be a module with '__file__' attribute"
                path = os.path.dirname(suppress_entity.__file__)
            else:
                path = suppress_entity
            path = os.path.normpath(os.path.abspath(path))
            self.suppress.append(path)
        self.max_frames = max(4, max_frames) if max_frames > 0 else 0
 
    @classmethod
    def from_exception(
        cls,
        exc_type: Type[Any],
        exc_value: BaseException,
        traceback: Optional[TracebackType],
        *,
        width: Optional[int] = 100,
        extra_lines: int = 3,
        theme: Optional[str] = None,
        word_wrap: bool = False,
        show_locals: bool = False,
        locals_max_length: int = LOCALS_MAX_LENGTH,
        locals_max_string: int = LOCALS_MAX_STRING,
        locals_hide_dunder: bool = True,
        locals_hide_sunder: bool = False,
        indent_guides: bool = True,
        suppress: Iterable[Union[str, ModuleType]] = (),
        max_frames: int = 100,
    ) -> "Traceback":
        """Create a traceback from exception info
 
        Args:
            exc_type (Type[BaseException]): Exception type.
            exc_value (BaseException): Exception value.
            traceback (TracebackType): Python Traceback object.
            width (Optional[int], optional): Number of characters used to traceback. Defaults to 100.
            extra_lines (int, optional): Additional lines of code to render. Defaults to 3.
            theme (str, optional): Override pygments theme used in traceback.
            word_wrap (bool, optional): Enable word wrapping of long lines. Defaults to False.
            show_locals (bool, optional): Enable display of local variables. Defaults to False.
            indent_guides (bool, optional): Enable indent guides in code and locals. Defaults to True.
            locals_max_length (int, optional): Maximum length of containers before abbreviating, or None for no abbreviation.
                Defaults to 10.
            locals_max_string (int, optional): Maximum length of string before truncating, or None to disable. Defaults to 80.
            locals_hide_dunder (bool, optional): Hide locals prefixed with double underscore. Defaults to True.
            locals_hide_sunder (bool, optional): Hide locals prefixed with single underscore. Defaults to False.
            suppress (Iterable[Union[str, ModuleType]]): Optional sequence of modules or paths to exclude from traceback.
            max_frames (int): Maximum number of frames to show in a traceback, 0 for no maximum. Defaults to 100.
 
        Returns:
            Traceback: A Traceback instance that may be printed.
        """
        rich_traceback = cls.extract(
            exc_type,
            exc_value,
            traceback,
            show_locals=show_locals,
            locals_max_length=locals_max_length,
            locals_max_string=locals_max_string,
            locals_hide_dunder=locals_hide_dunder,
            locals_hide_sunder=locals_hide_sunder,
        )
 
        return cls(
            rich_traceback,
            width=width,
            extra_lines=extra_lines,
            theme=theme,
            word_wrap=word_wrap,
            show_locals=show_locals,
            indent_guides=indent_guides,
            locals_max_length=locals_max_length,
            locals_max_string=locals_max_string,
            locals_hide_dunder=locals_hide_dunder,
            locals_hide_sunder=locals_hide_sunder,
            suppress=suppress,
            max_frames=max_frames,
        )
 
    @classmethod
    def extract(
        cls,
        exc_type: Type[BaseException],
        exc_value: BaseException,
        traceback: Optional[TracebackType],
        *,
        show_locals: bool = False,
        locals_max_length: int = LOCALS_MAX_LENGTH,
        locals_max_string: int = LOCALS_MAX_STRING,
        locals_hide_dunder: bool = True,
        locals_hide_sunder: bool = False,
    ) -> Trace:
        """Extract traceback information.
 
        Args:
            exc_type (Type[BaseException]): Exception type.
            exc_value (BaseException): Exception value.
            traceback (TracebackType): Python Traceback object.
            show_locals (bool, optional): Enable display of local variables. Defaults to False.
            locals_max_length (int, optional): Maximum length of containers before abbreviating, or None for no abbreviation.
                Defaults to 10.
            locals_max_string (int, optional): Maximum length of string before truncating, or None to disable. Defaults to 80.
            locals_hide_dunder (bool, optional): Hide locals prefixed with double underscore. Defaults to True.
            locals_hide_sunder (bool, optional): Hide locals prefixed with single underscore. Defaults to False.
 
        Returns:
            Trace: A Trace instance which you can use to construct a `Traceback`.
        """
 
        stacks: List[Stack] = []
        is_cause = False
 
        from pip._vendor.rich import _IMPORT_CWD
 
        def safe_str(_object: Any) -> str:
            """Don't allow exceptions from __str__ to propagate."""
            try:
                return str(_object)
            except Exception:
                return "<exception str() failed>"
 
        while True:
            stack = Stack(
                exc_type=safe_str(exc_type.__name__),
                exc_value=safe_str(exc_value),
                is_cause=is_cause,
            )
 
            if isinstance(exc_value, SyntaxError):
                stack.syntax_error = _SyntaxError(
                    offset=exc_value.offset or 0,
                    filename=exc_value.filename or "?",
                    lineno=exc_value.lineno or 0,
                    line=exc_value.text or "",
                    msg=exc_value.msg,
                )
 
            stacks.append(stack)
            append = stack.frames.append
 
            def get_locals(
                iter_locals: Iterable[Tuple[str, object]]
            ) -> Iterable[Tuple[str, object]]:
                """Extract locals from an iterator of key pairs."""
                if not (locals_hide_dunder or locals_hide_sunder):
                    yield from iter_locals
                    return
                for key, value in iter_locals:
                    if locals_hide_dunder and key.startswith("__"):
                        continue
                    if locals_hide_sunder and key.startswith("_"):
                        continue
                    yield key, value
 
            for frame_summary, line_no in walk_tb(traceback):
                filename = frame_summary.f_code.co_filename
                if filename and not filename.startswith("<"):
                    if not os.path.isabs(filename):
                        filename = os.path.join(_IMPORT_CWD, filename)
                if frame_summary.f_locals.get("_rich_traceback_omit", False):
                    continue
 
                frame = Frame(
                    filename=filename or "?",
                    lineno=line_no,
                    name=frame_summary.f_code.co_name,
                    locals={
                        key: pretty.traverse(
                            value,
                            max_length=locals_max_length,
                            max_string=locals_max_string,
                        )
                        for key, value in get_locals(frame_summary.f_locals.items())
                    }
                    if show_locals
                    else None,
                )
                append(frame)
                if frame_summary.f_locals.get("_rich_traceback_guard", False):
                    del stack.frames[:]
 
            cause = getattr(exc_value, "__cause__", None)
            if cause:
                exc_type = cause.__class__
                exc_value = cause
                # __traceback__ can be None, e.g. for exceptions raised by the
                # 'multiprocessing' module
                traceback = cause.__traceback__
                is_cause = True
                continue
 
            cause = exc_value.__context__
            if cause and not getattr(exc_value, "__suppress_context__", False):
                exc_type = cause.__class__
                exc_value = cause
                traceback = cause.__traceback__
                is_cause = False
                continue
            # No cover, code is reached but coverage doesn't recognize it.
            break  # pragma: no cover
 
        trace = Trace(stacks=stacks)
        return trace
 
    def __rich_console__(
        self, console: Console, options: ConsoleOptions
    ) -> RenderResult:
        theme = self.theme
        background_style = theme.get_background_style()
        token_style = theme.get_style_for_token
 
        traceback_theme = Theme(
            {
                "pretty": token_style(TextToken),
                "pygments.text": token_style(Token),
                "pygments.string": token_style(String),
                "pygments.function": token_style(Name.Function),
                "pygments.number": token_style(Number),
                "repr.indent": token_style(Comment) + Style(dim=True),
                "repr.str": token_style(String),
                "repr.brace": token_style(TextToken) + Style(bold=True),
                "repr.number": token_style(Number),
                "repr.bool_true": token_style(Keyword.Constant),
                "repr.bool_false": token_style(Keyword.Constant),
                "repr.none": token_style(Keyword.Constant),
                "scope.border": token_style(String.Delimiter),
                "scope.equals": token_style(Operator),
                "scope.key": token_style(Name),
                "scope.key.special": token_style(Name.Constant) + Style(dim=True),
            },
            inherit=False,
        )
 
        highlighter = ReprHighlighter()
        for last, stack in loop_last(reversed(self.trace.stacks)):
            if stack.frames:
                stack_renderable: ConsoleRenderable = Panel(
                    self._render_stack(stack),
                    title="[traceback.title]Traceback [dim](most recent call last)",
                    style=background_style,
                    border_style="traceback.border",
                    expand=True,
                    padding=(0, 1),
                )
                stack_renderable = Constrain(stack_renderable, self.width)
                with console.use_theme(traceback_theme):
                    yield stack_renderable
            if stack.syntax_error is not None:
                with console.use_theme(traceback_theme):
                    yield Constrain(
                        Panel(
                            self._render_syntax_error(stack.syntax_error),
                            style=background_style,
                            border_style="traceback.border.syntax_error",
                            expand=True,
                            padding=(0, 1),
                            width=self.width,
                        ),
                        self.width,
                    )
                yield Text.assemble(
                    (f"{stack.exc_type}: ", "traceback.exc_type"),
                    highlighter(stack.syntax_error.msg),
                )
            elif stack.exc_value:
                yield Text.assemble(
                    (f"{stack.exc_type}: ", "traceback.exc_type"),
                    highlighter(stack.exc_value),
                )
            else:
                yield Text.assemble((f"{stack.exc_type}", "traceback.exc_type"))
 
            if not last:
                if stack.is_cause:
                    yield Text.from_markup(
                        "\n[i]The above exception was the direct cause of the following exception:\n",
                    )
                else:
                    yield Text.from_markup(
                        "\n[i]During handling of the above exception, another exception occurred:\n",
                    )
 
    @group()
    def _render_syntax_error(self, syntax_error: _SyntaxError) -> RenderResult:
        highlighter = ReprHighlighter()
        path_highlighter = PathHighlighter()
        if syntax_error.filename != "<stdin>":
            if os.path.exists(syntax_error.filename):
                text = Text.assemble(
                    (f" {syntax_error.filename}", "pygments.string"),
                    (":", "pygments.text"),
                    (str(syntax_error.lineno), "pygments.number"),
                    style="pygments.text",
                )
                yield path_highlighter(text)
        syntax_error_text = highlighter(syntax_error.line.rstrip())
        syntax_error_text.no_wrap = True
        offset = min(syntax_error.offset - 1, len(syntax_error_text))
        syntax_error_text.stylize("bold underline", offset, offset)
        syntax_error_text += Text.from_markup(
            "\n" + " " * offset + "[traceback.offset]▲[/]",
            style="pygments.text",
        )
        yield syntax_error_text
 
    @classmethod
    def _guess_lexer(cls, filename: str, code: str) -> str:
        ext = os.path.splitext(filename)[-1]
        if not ext:
            # No extension, look at first line to see if it is a hashbang
            # Note, this is an educated guess and not a guarantee
            # If it fails, the only downside is that the code is highlighted strangely
            new_line_index = code.index("\n")
            first_line = code[:new_line_index] if new_line_index != -1 else code
            if first_line.startswith("#!") and "python" in first_line.lower():
                return "python"
        try:
            return cls.LEXERS.get(ext) or guess_lexer_for_filename(filename, code).name
        except ClassNotFound:
            return "text"
 
    @group()
    def _render_stack(self, stack: Stack) -> RenderResult:
        path_highlighter = PathHighlighter()
        theme = self.theme
 
        def read_code(filename: str) -> str:
            """Read files, and cache results on filename.
 
            Args:
                filename (str): Filename to read
 
            Returns:
                str: Contents of file
            """
            return "".join(linecache.getlines(filename))
 
        def render_locals(frame: Frame) -> Iterable[ConsoleRenderable]:
            if frame.locals:
                yield render_scope(
                    frame.locals,
                    title="locals",
                    indent_guides=self.indent_guides,
                    max_length=self.locals_max_length,
                    max_string=self.locals_max_string,
                )
 
        exclude_frames: Optional[range] = None
        if self.max_frames != 0:
            exclude_frames = range(
                self.max_frames // 2,
                len(stack.frames) - self.max_frames // 2,
            )
 
        excluded = False
        for frame_index, frame in enumerate(stack.frames):
 
            if exclude_frames and frame_index in exclude_frames:
                excluded = True
                continue
 
            if excluded:
                assert exclude_frames is not None
                yield Text(
                    f"\n... {len(exclude_frames)} frames hidden ...",
                    justify="center",
                    style="traceback.error",
                )
                excluded = False
 
            first = frame_index == 0
            frame_filename = frame.filename
            suppressed = any(frame_filename.startswith(path) for path in self.suppress)
 
            if os.path.exists(frame.filename):
                text = Text.assemble(
                    path_highlighter(Text(frame.filename, style="pygments.string")),
                    (":", "pygments.text"),
                    (str(frame.lineno), "pygments.number"),
                    " in ",
                    (frame.name, "pygments.function"),
                    style="pygments.text",
                )
            else:
                text = Text.assemble(
                    "in ",
                    (frame.name, "pygments.function"),
                    (":", "pygments.text"),
                    (str(frame.lineno), "pygments.number"),
                    style="pygments.text",
                )
            if not frame.filename.startswith("<") and not first:
                yield ""
            yield text
            if frame.filename.startswith("<"):
                yield from render_locals(frame)
                continue
            if not suppressed:
                try:
                    code = read_code(frame.filename)
                    if not code:
                        # code may be an empty string if the file doesn't exist, OR
                        # if the traceback filename is generated dynamically
                        continue
                    lexer_name = self._guess_lexer(frame.filename, code)
                    syntax = Syntax(
                        code,
                        lexer_name,
                        theme=theme,
                        line_numbers=True,
                        line_range=(
                            frame.lineno - self.extra_lines,
                            frame.lineno + self.extra_lines,
                        ),
                        highlight_lines={frame.lineno},
                        word_wrap=self.word_wrap,
                        code_width=88,
                        indent_guides=self.indent_guides,
                        dedent=False,
                    )
                    yield ""
                except Exception as error:
                    yield Text.assemble(
                        (f"\n{error}", "traceback.error"),
                    )
                else:
                    yield (
                        Columns(
                            [
                                syntax,
                                *render_locals(frame),
                            ],
                            padding=1,
                        )
                        if frame.locals
                        else syntax
                    )
 
 
if __name__ == "__main__":  # pragma: no cover
 
    from .console import Console
 
    console = Console()
    import sys
 
    def bar(a: Any) -> None:  # 这是对亚洲语言支持的测试。面对模棱两可的想法，拒绝猜测的诱惑
        one = 1
        print(one / a)
 
    def foo(a: Any) -> None:
        _rich_traceback_guard = True
        zed = {
            "characters": {
                "Paul Atreides",
                "Vladimir Harkonnen",
                "Thufir Hawat",
                "Duncan Idaho",
            },
            "atomic_types": (None, False, True),
        }
        bar(a)
 
    def error() -> None:
 
        try:
            try:
                foo(0)
            except:
                slfkjsldkfj  # type: ignore[name-defined]
        except:
            console.print_exception(show_locals=True)
 
    error()