Library import 16 (#2433)

Co-authored-by: robot-piglet <robot-piglet@yandex-team.com>
Co-authored-by: deshevoy <deshevoy@yandex-team.com>
Co-authored-by: robot-contrib <robot-contrib@yandex-team.com>
Co-authored-by: thegeorg <thegeorg@yandex-team.com>
Co-authored-by: robot-ya-builder <robot-ya-builder@yandex-team.com>
Co-authored-by: svidyuk <svidyuk@yandex-team.com>
Co-authored-by: shadchin <shadchin@yandex-team.com>
Co-authored-by: robot-ratatosk <robot-ratatosk@yandex-team.com>
Co-authored-by: innokentii <innokentii@yandex-team.com>
Co-authored-by: arkady-e1ppa <arkady-e1ppa@yandex-team.com>
Co-authored-by: snermolaev <snermolaev@yandex-team.com>
Co-authored-by: dimdim11 <dimdim11@yandex-team.com>
Co-authored-by: kickbutt <kickbutt@yandex-team.com>
Co-authored-by: abdullinsaid <abdullinsaid@yandex-team.com>
Co-authored-by: korsunandrei <korsunandrei@yandex-team.com>
Co-authored-by: petrk <petrk@yandex-team.com>
Co-authored-by: miroslav2 <miroslav2@yandex-team.com>
Co-authored-by: serjflint <serjflint@yandex-team.com>
Co-authored-by: akhropov <akhropov@yandex-team.com>
Co-authored-by: prettyboy <prettyboy@yandex-team.com>
Co-authored-by: ilikepugs <ilikepugs@yandex-team.com>
Co-authored-by: hiddenpath <hiddenpath@yandex-team.com>
Co-authored-by: mikhnenko <mikhnenko@yandex-team.com>
Co-authored-by: spreis <spreis@yandex-team.com>
Co-authored-by: andreyshspb <andreyshspb@yandex-team.com>
Co-authored-by: dimaandreev <dimaandreev@yandex-team.com>
Co-authored-by: rashid <rashid@yandex-team.com>
Co-authored-by: robot-ydb-importer <robot-ydb-importer@yandex-team.com>
Co-authored-by: r-vetrov <r-vetrov@yandex-team.com>
Co-authored-by: ypodlesov <ypodlesov@yandex-team.com>
Co-authored-by: zaverden <zaverden@yandex-team.com>
Co-authored-by: vpozdyayev <vpozdyayev@yandex-team.com>
Co-authored-by: robot-cozmo <robot-cozmo@yandex-team.com>
Co-authored-by: v-korovin <v-korovin@yandex-team.com>
Co-authored-by: arikon <arikon@yandex-team.com>
Co-authored-by: khoden <khoden@yandex-team.com>
Co-authored-by: psydmm <psydmm@yandex-team.com>
Co-authored-by: robot-javacom <robot-javacom@yandex-team.com>
Co-authored-by: dtorilov <dtorilov@yandex-team.com>
Co-authored-by: sennikovmv <sennikovmv@yandex-team.com>
Co-authored-by: hcpp <hcpp@ydb.tech>

1 files changed, 1187 insertions, 0 deletions

diff --git a/contrib/tools/python3/Lib/traceback.py b/contrib/tools/python3/Lib/traceback.py
new file mode 100644
index 0000000000..8247d8ff8c
--- /dev/null
+++ b/contrib/tools/python3/Lib/traceback.py
@@ -0,0 +1,1187 @@
+"""Extract, format and print information about Python stack traces."""
+
+import collections.abc
+import itertools
+import linecache
+import sys
+import textwrap
+from contextlib import suppress
+
+__all__ = ['extract_stack', 'extract_tb', 'format_exception',
+           'format_exception_only', 'format_list', 'format_stack',
+           'format_tb', 'print_exc', 'format_exc', 'print_exception',
+           'print_last', 'print_stack', 'print_tb', 'clear_frames',
+           'FrameSummary', 'StackSummary', 'TracebackException',
+           'walk_stack', 'walk_tb']
+
+#
+# Formatting and printing lists of traceback lines.
+#
+
+def print_list(extracted_list, file=None):
+    """Print the list of tuples as returned by extract_tb() or
+    extract_stack() as a formatted stack trace to the given file."""
+    if file is None:
+        file = sys.stderr
+    for item in StackSummary.from_list(extracted_list).format():
+        print(item, file=file, end="")
+
+def format_list(extracted_list):
+    """Format a list of tuples or FrameSummary objects for printing.
+
+    Given a list of tuples or FrameSummary objects as returned by
+    extract_tb() or extract_stack(), return a list of strings ready
+    for printing.
+
+    Each string in the resulting list corresponds to the item with the
+    same index in the argument list.  Each string ends in a newline;
+    the strings may contain internal newlines as well, for those items
+    whose source text line is not None.
+    """
+    return StackSummary.from_list(extracted_list).format()
+
+#
+# Printing and Extracting Tracebacks.
+#
+
+def print_tb(tb, limit=None, file=None):
+    """Print up to 'limit' stack trace entries from the traceback 'tb'.
+
+    If 'limit' is omitted or None, all entries are printed.  If 'file'
+    is omitted or None, the output goes to sys.stderr; otherwise
+    'file' should be an open file or file-like object with a write()
+    method.
+    """
+    print_list(extract_tb(tb, limit=limit), file=file)
+
+def format_tb(tb, limit=None):
+    """A shorthand for 'format_list(extract_tb(tb, limit))'."""
+    return extract_tb(tb, limit=limit).format()
+
+def extract_tb(tb, limit=None):
+    """
+    Return a StackSummary object representing a list of
+    pre-processed entries from traceback.
+
+    This is useful for alternate formatting of stack traces.  If
+    'limit' is omitted or None, all entries are extracted.  A
+    pre-processed stack trace entry is a FrameSummary object
+    containing attributes filename, lineno, name, and line
+    representing the information that is usually printed for a stack
+    trace.  The line is a string with leading and trailing
+    whitespace stripped; if the source is not available it is None.
+    """
+    return StackSummary._extract_from_extended_frame_gen(
+        _walk_tb_with_full_positions(tb), limit=limit)
+
+#
+# Exception formatting and output.
+#
+
+_cause_message = (
+    "\nThe above exception was the direct cause "
+    "of the following exception:\n\n")
+
+_context_message = (
+    "\nDuring handling of the above exception, "
+    "another exception occurred:\n\n")
+
+
+class _Sentinel:
+    def __repr__(self):
+        return "<implicit>"
+
+_sentinel = _Sentinel()
+
+def _parse_value_tb(exc, value, tb):
+    if (value is _sentinel) != (tb is _sentinel):
+        raise ValueError("Both or neither of value and tb must be given")
+    if value is tb is _sentinel:
+        if exc is not None:
+            if isinstance(exc, BaseException):
+                return exc, exc.__traceback__
+
+            raise TypeError(f'Exception expected for value, '
+                            f'{type(exc).__name__} found')
+        else:
+            return None, None
+    return value, tb
+
+
+def print_exception(exc, /, value=_sentinel, tb=_sentinel, limit=None, \
+                    file=None, chain=True):
+    """Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
+
+    This differs from print_tb() in the following ways: (1) if
+    traceback is not None, it prints a header "Traceback (most recent
+    call last):"; (2) it prints the exception type and value after the
+    stack trace; (3) if type is SyntaxError and value has the
+    appropriate format, it prints the line where the syntax error
+    occurred with a caret on the next line indicating the approximate
+    position of the error.
+    """
+    value, tb = _parse_value_tb(exc, value, tb)
+    te = TracebackException(type(value), value, tb, limit=limit, compact=True)
+    te.print(file=file, chain=chain)
+
+
+def format_exception(exc, /, value=_sentinel, tb=_sentinel, limit=None, \
+                     chain=True):
+    """Format a stack trace and the exception information.
+
+    The arguments have the same meaning as the corresponding arguments
+    to print_exception().  The return value is a list of strings, each
+    ending in a newline and some containing internal newlines.  When
+    these lines are concatenated and printed, exactly the same text is
+    printed as does print_exception().
+    """
+    value, tb = _parse_value_tb(exc, value, tb)
+    te = TracebackException(type(value), value, tb, limit=limit, compact=True)
+    return list(te.format(chain=chain))
+
+
+def format_exception_only(exc, /, value=_sentinel):
+    """Format the exception part of a traceback.
+
+    The return value is a list of strings, each ending in a newline.
+
+    The list contains the exception's message, which is
+    normally a single string; however, for :exc:`SyntaxError` exceptions, it
+    contains several lines that (when printed) display detailed information
+    about where the syntax error occurred. Following the message, the list
+    contains the exception's ``__notes__``.
+    """
+    if value is _sentinel:
+        value = exc
+    te = TracebackException(type(value), value, None, compact=True)
+    return list(te.format_exception_only())
+
+
+# -- not official API but folk probably use these two functions.
+
+def _format_final_exc_line(etype, value):
+    valuestr = _safe_string(value, 'exception')
+    if value is None or not valuestr:
+        line = "%s\n" % etype
+    else:
+        line = "%s: %s\n" % (etype, valuestr)
+    return line
+
+def _safe_string(value, what, func=str):
+    try:
+        return func(value)
+    except:
+        return f'<{what} {func.__name__}() failed>'
+
+# --
+
+def print_exc(limit=None, file=None, chain=True):
+    """Shorthand for 'print_exception(sys.exception(), limit, file, chain)'."""
+    print_exception(sys.exception(), limit=limit, file=file, chain=chain)
+
+def format_exc(limit=None, chain=True):
+    """Like print_exc() but return a string."""
+    return "".join(format_exception(sys.exception(), limit=limit, chain=chain))
+
+def print_last(limit=None, file=None, chain=True):
+    """This is a shorthand for 'print_exception(sys.last_exc, limit, file, chain)'."""
+    if not hasattr(sys, "last_exc") and not hasattr(sys, "last_type"):
+        raise ValueError("no last exception")
+
+    if hasattr(sys, "last_exc"):
+        print_exception(sys.last_exc, limit, file, chain)
+    else:
+        print_exception(sys.last_type, sys.last_value, sys.last_traceback,
+                        limit, file, chain)
+
+
+#
+# Printing and Extracting Stacks.
+#
+
+def print_stack(f=None, limit=None, file=None):
+    """Print a stack trace from its invocation point.
+
+    The optional 'f' argument can be used to specify an alternate
+    stack frame at which to start. The optional 'limit' and 'file'
+    arguments have the same meaning as for print_exception().
+    """
+    if f is None:
+        f = sys._getframe().f_back
+    print_list(extract_stack(f, limit=limit), file=file)
+
+
+def format_stack(f=None, limit=None):
+    """Shorthand for 'format_list(extract_stack(f, limit))'."""
+    if f is None:
+        f = sys._getframe().f_back
+    return format_list(extract_stack(f, limit=limit))
+
+
+def extract_stack(f=None, limit=None):
+    """Extract the raw traceback from the current stack frame.
+
+    The return value has the same format as for extract_tb().  The
+    optional 'f' and 'limit' arguments have the same meaning as for
+    print_stack().  Each item in the list is a quadruple (filename,
+    line number, function name, text), and the entries are in order
+    from oldest to newest stack frame.
+    """
+    if f is None:
+        f = sys._getframe().f_back
+    stack = StackSummary.extract(walk_stack(f), limit=limit)
+    stack.reverse()
+    return stack
+
+
+def clear_frames(tb):
+    "Clear all references to local variables in the frames of a traceback."
+    while tb is not None:
+        try:
+            tb.tb_frame.clear()
+        except RuntimeError:
+            # Ignore the exception raised if the frame is still executing.
+            pass
+        tb = tb.tb_next
+
+
+class FrameSummary:
+    """Information about a single frame from a traceback.
+
+    - :attr:`filename` The filename for the frame.
+    - :attr:`lineno` The line within filename for the frame that was
+      active when the frame was captured.
+    - :attr:`name` The name of the function or method that was executing
+      when the frame was captured.
+    - :attr:`line` The text from the linecache module for the
+      of code that was running when the frame was captured.
+    - :attr:`locals` Either None if locals were not supplied, or a dict
+      mapping the name to the repr() of the variable.
+    """
+
+    __slots__ = ('filename', 'lineno', 'end_lineno', 'colno', 'end_colno',
+                 'name', '_line', 'locals')
+
+    def __init__(self, filename, lineno, name, *, lookup_line=True,
+            locals=None, line=None,
+            end_lineno=None, colno=None, end_colno=None):
+        """Construct a FrameSummary.
+
+        :param lookup_line: If True, `linecache` is consulted for the source
+            code line. Otherwise, the line will be looked up when first needed.
+        :param locals: If supplied the frame locals, which will be captured as
+            object representations.
+        :param line: If provided, use this instead of looking up the line in
+            the linecache.
+        """
+        self.filename = filename
+        self.lineno = lineno
+        self.name = name
+        self._line = line
+        if lookup_line:
+            self.line
+        self.locals = {k: _safe_string(v, 'local', func=repr)
+            for k, v in locals.items()} if locals else None
+        self.end_lineno = end_lineno
+        self.colno = colno
+        self.end_colno = end_colno
+
+    def __eq__(self, other):
+        if isinstance(other, FrameSummary):
+            return (self.filename == other.filename and
+                    self.lineno == other.lineno and
+                    self.name == other.name and
+                    self.locals == other.locals)
+        if isinstance(other, tuple):
+            return (self.filename, self.lineno, self.name, self.line) == other
+        return NotImplemented
+
+    def __getitem__(self, pos):
+        return (self.filename, self.lineno, self.name, self.line)[pos]
+
+    def __iter__(self):
+        return iter([self.filename, self.lineno, self.name, self.line])
+
+    def __repr__(self):
+        return "<FrameSummary file {filename}, line {lineno} in {name}>".format(
+            filename=self.filename, lineno=self.lineno, name=self.name)
+
+    def __len__(self):
+        return 4
+
+    @property
+    def _original_line(self):
+        # Returns the line as-is from the source, without modifying whitespace.
+        self.line
+        return self._line
+
+    @property
+    def line(self):
+        if self._line is None:
+            if self.lineno is None:
+                return None
+            self._line = linecache.getline(self.filename, self.lineno)
+        return self._line.strip()
+
+
+def walk_stack(f):
+    """Walk a stack yielding the frame and line number for each frame.
+
+    This will follow f.f_back from the given frame. If no frame is given, the
+    current stack is used. Usually used with StackSummary.extract.
+    """
+    if f is None:
+        f = sys._getframe().f_back.f_back.f_back.f_back
+    while f is not None:
+        yield f, f.f_lineno
+        f = f.f_back
+
+
+def walk_tb(tb):
+    """Walk a traceback yielding the frame and line number for each frame.
+
+    This will follow tb.tb_next (and thus is in the opposite order to
+    walk_stack). Usually used with StackSummary.extract.
+    """
+    while tb is not None:
+        yield tb.tb_frame, tb.tb_lineno
+        tb = tb.tb_next
+
+
+def _walk_tb_with_full_positions(tb):
+    # Internal version of walk_tb that yields full code positions including
+    # end line and column information.
+    while tb is not None:
+        positions = _get_code_position(tb.tb_frame.f_code, tb.tb_lasti)
+        # Yield tb_lineno when co_positions does not have a line number to
+        # maintain behavior with walk_tb.
+        if positions[0] is None:
+            yield tb.tb_frame, (tb.tb_lineno, ) + positions[1:]
+        else:
+            yield tb.tb_frame, positions
+        tb = tb.tb_next
+
+
+def _get_code_position(code, instruction_index):
+    if instruction_index < 0:
+        return (None, None, None, None)
+    positions_gen = code.co_positions()
+    return next(itertools.islice(positions_gen, instruction_index // 2, None))
+
+
+_RECURSIVE_CUTOFF = 3 # Also hardcoded in traceback.c.
+
+class StackSummary(list):
+    """A list of FrameSummary objects, representing a stack of frames."""
+
+    @classmethod
+    def extract(klass, frame_gen, *, limit=None, lookup_lines=True,
+            capture_locals=False):
+        """Create a StackSummary from a traceback or stack object.
+
+        :param frame_gen: A generator that yields (frame, lineno) tuples
+            whose summaries are to be included in the stack.
+        :param limit: None to include all frames or the number of frames to
+            include.
+        :param lookup_lines: If True, lookup lines for each frame immediately,
+            otherwise lookup is deferred until the frame is rendered.
+        :param capture_locals: If True, the local variables from each frame will
+            be captured as object representations into the FrameSummary.
+        """
+        def extended_frame_gen():
+            for f, lineno in frame_gen:
+                yield f, (lineno, None, None, None)
+
+        return klass._extract_from_extended_frame_gen(
+            extended_frame_gen(), limit=limit, lookup_lines=lookup_lines,
+            capture_locals=capture_locals)
+
+    @classmethod
+    def _extract_from_extended_frame_gen(klass, frame_gen, *, limit=None,
+            lookup_lines=True, capture_locals=False):
+        # Same as extract but operates on a frame generator that yields
+        # (frame, (lineno, end_lineno, colno, end_colno)) in the stack.
+        # Only lineno is required, the remaining fields can be None if the
+        # information is not available.
+        if limit is None:
+            limit = getattr(sys, 'tracebacklimit', None)
+            if limit is not None and limit < 0:
+                limit = 0
+        if limit is not None:
+            if limit >= 0:
+                frame_gen = itertools.islice(frame_gen, limit)
+            else:
+                frame_gen = collections.deque(frame_gen, maxlen=-limit)
+
+        result = klass()
+        fnames = set()
+        for f, (lineno, end_lineno, colno, end_colno) in frame_gen:
+            co = f.f_code
+            filename = co.co_filename
+            name = co.co_name
+
+            fnames.add(filename)
+            linecache.lazycache(filename, f.f_globals)
+            # Must defer line lookups until we have called checkcache.
+            if capture_locals:
+                f_locals = f.f_locals
+            else:
+                f_locals = None
+            result.append(FrameSummary(
+                filename, lineno, name, lookup_line=False, locals=f_locals,
+                end_lineno=end_lineno, colno=colno, end_colno=end_colno))
+        for filename in fnames:
+            linecache.checkcache(filename)
+        # If immediate lookup was desired, trigger lookups now.
+        if lookup_lines:
+            for f in result:
+                f.line
+        return result
+
+    @classmethod
+    def from_list(klass, a_list):
+        """
+        Create a StackSummary object from a supplied list of
+        FrameSummary objects or old-style list of tuples.
+        """
+        # While doing a fast-path check for isinstance(a_list, StackSummary) is
+        # appealing, idlelib.run.cleanup_traceback and other similar code may
+        # break this by making arbitrary frames plain tuples, so we need to
+        # check on a frame by frame basis.
+        result = StackSummary()
+        for frame in a_list:
+            if isinstance(frame, FrameSummary):
+                result.append(frame)
+            else:
+                filename, lineno, name, line = frame
+                result.append(FrameSummary(filename, lineno, name, line=line))
+        return result
+
+    def format_frame_summary(self, frame_summary):
+        """Format the lines for a single FrameSummary.
+
+        Returns a string representing one frame involved in the stack. This
+        gets called for every frame to be printed in the stack summary.
+        """
+        row = []
+        row.append('  File "{}", line {}, in {}\n'.format(
+            frame_summary.filename, frame_summary.lineno, frame_summary.name))
+        if frame_summary.line:
+            stripped_line = frame_summary.line.strip()
+            row.append('    {}\n'.format(stripped_line))
+
+            line = frame_summary._original_line
+            orig_line_len = len(line)
+            frame_line_len = len(frame_summary.line.lstrip())
+            stripped_characters = orig_line_len - frame_line_len
+            if (
+                frame_summary.colno is not None
+                and frame_summary.end_colno is not None
+            ):
+                start_offset = _byte_offset_to_character_offset(
+                    line, frame_summary.colno)
+                end_offset = _byte_offset_to_character_offset(
+                    line, frame_summary.end_colno)
+                code_segment = line[start_offset:end_offset]
+
+                anchors = None
+                if frame_summary.lineno == frame_summary.end_lineno:
+                    with suppress(Exception):
+                        anchors = _extract_caret_anchors_from_line_segment(code_segment)
+                else:
+                    # Don't count the newline since the anchors only need to
+                    # go up until the last character of the line.
+                    end_offset = len(line.rstrip())
+
+                # show indicators if primary char doesn't span the frame line
+                if end_offset - start_offset < len(stripped_line) or (
+                        anchors and anchors.right_start_offset - anchors.left_end_offset > 0):
+                    # When showing this on a terminal, some of the non-ASCII characters
+                    # might be rendered as double-width characters, so we need to take
+                    # that into account when calculating the length of the line.
+                    dp_start_offset = _display_width(line, start_offset) + 1
+                    dp_end_offset = _display_width(line, end_offset) + 1
+
+                    row.append('    ')
+                    row.append(' ' * (dp_start_offset - stripped_characters))
+
+                    if anchors:
+                        dp_left_end_offset = _display_width(code_segment, anchors.left_end_offset)
+                        dp_right_start_offset = _display_width(code_segment, anchors.right_start_offset)
+                        row.append(anchors.primary_char * dp_left_end_offset)
+                        row.append(anchors.secondary_char * (dp_right_start_offset - dp_left_end_offset))
+                        row.append(anchors.primary_char * (dp_end_offset - dp_start_offset - dp_right_start_offset))
+                    else:
+                        row.append('^' * (dp_end_offset - dp_start_offset))
+
+                    row.append('\n')
+
+        if frame_summary.locals:
+            for name, value in sorted(frame_summary.locals.items()):
+                row.append('    {name} = {value}\n'.format(name=name, value=value))
+
+        return ''.join(row)
+
+    def format(self):
+        """Format the stack ready for printing.
+
+        Returns a list of strings ready for printing.  Each string in the
+        resulting list corresponds to a single frame from the stack.
+        Each string ends in a newline; the strings may contain internal
+        newlines as well, for those items with source text lines.
+
+        For long sequences of the same frame and line, the first few
+        repetitions are shown, followed by a summary line stating the exact
+        number of further repetitions.
+        """
+        result = []
+        last_file = None
+        last_line = None
+        last_name = None
+        count = 0
+        for frame_summary in self:
+            formatted_frame = self.format_frame_summary(frame_summary)
+            if formatted_frame is None:
+                continue
+            if (last_file is None or last_file != frame_summary.filename or
+                last_line is None or last_line != frame_summary.lineno or
+                last_name is None or last_name != frame_summary.name):
+                if count > _RECURSIVE_CUTOFF:
+                    count -= _RECURSIVE_CUTOFF
+                    result.append(
+                        f'  [Previous line repeated {count} more '
+                        f'time{"s" if count > 1 else ""}]\n'
+                    )
+                last_file = frame_summary.filename
+                last_line = frame_summary.lineno
+                last_name = frame_summary.name
+                count = 0
+            count += 1
+            if count > _RECURSIVE_CUTOFF:
+                continue
+            result.append(formatted_frame)
+
+        if count > _RECURSIVE_CUTOFF:
+            count -= _RECURSIVE_CUTOFF
+            result.append(
+                f'  [Previous line repeated {count} more '
+                f'time{"s" if count > 1 else ""}]\n'
+            )
+        return result
+
+
+def _byte_offset_to_character_offset(str, offset):
+    as_utf8 = str.encode('utf-8')
+    return len(as_utf8[:offset].decode("utf-8", errors="replace"))
+
+
+_Anchors = collections.namedtuple(
+    "_Anchors",
+    [
+        "left_end_offset",
+        "right_start_offset",
+        "primary_char",
+        "secondary_char",
+    ],
+    defaults=["~", "^"]
+)
+
+def _extract_caret_anchors_from_line_segment(segment):
+    import ast
+
+    try:
+        tree = ast.parse(segment)
+    except SyntaxError:
+        return None
+
+    if len(tree.body) != 1:
+        return None
+
+    normalize = lambda offset: _byte_offset_to_character_offset(segment, offset)
+    statement = tree.body[0]
+    match statement:
+        case ast.Expr(expr):
+            match expr:
+                case ast.BinOp():
+                    operator_start = normalize(expr.left.end_col_offset)
+                    operator_end = normalize(expr.right.col_offset)
+                    operator_str = segment[operator_start:operator_end]
+                    operator_offset = len(operator_str) - len(operator_str.lstrip())
+
+                    left_anchor = expr.left.end_col_offset + operator_offset
+                    right_anchor = left_anchor + 1
+                    if (
+                        operator_offset + 1 < len(operator_str)
+                        and not operator_str[operator_offset + 1].isspace()
+                    ):
+                        right_anchor += 1
+
+                    while left_anchor < len(segment) and ((ch := segment[left_anchor]).isspace() or ch in ")#"):
+                        left_anchor += 1
+                        right_anchor += 1
+                    return _Anchors(normalize(left_anchor), normalize(right_anchor))
+                case ast.Subscript():
+                    left_anchor = normalize(expr.value.end_col_offset)
+                    right_anchor = normalize(expr.slice.end_col_offset + 1)
+                    while left_anchor < len(segment) and ((ch := segment[left_anchor]).isspace() or ch != "["):
+                        left_anchor += 1
+                    while right_anchor < len(segment) and ((ch := segment[right_anchor]).isspace() or ch != "]"):
+                        right_anchor += 1
+                    if right_anchor < len(segment):
+                        right_anchor += 1
+                    return _Anchors(left_anchor, right_anchor)
+
+    return None
+
+_WIDE_CHAR_SPECIFIERS = "WF"
+
+def _display_width(line, offset):
+    """Calculate the extra amount of width space the given source
+    code segment might take if it were to be displayed on a fixed
+    width output device. Supports wide unicode characters and emojis."""
+
+    # Fast track for ASCII-only strings
+    if line.isascii():
+        return offset
+
+    import unicodedata
+
+    return sum(
+        2 if unicodedata.east_asian_width(char) in _WIDE_CHAR_SPECIFIERS else 1
+        for char in line[:offset]
+    )
+
+
+
+class _ExceptionPrintContext:
+    def __init__(self):
+        self.seen = set()
+        self.exception_group_depth = 0
+        self.need_close = False
+
+    def indent(self):
+        return ' ' * (2 * self.exception_group_depth)
+
+    def emit(self, text_gen, margin_char=None):
+        if margin_char is None:
+            margin_char = '|'
+        indent_str = self.indent()
+        if self.exception_group_depth:
+            indent_str += margin_char + ' '
+
+        if isinstance(text_gen, str):
+            yield textwrap.indent(text_gen, indent_str, lambda line: True)
+        else:
+            for text in text_gen:
+                yield textwrap.indent(text, indent_str, lambda line: True)
+
+
+class TracebackException:
+    """An exception ready for rendering.
+
+    The traceback module captures enough attributes from the original exception
+    to this intermediary form to ensure that no references are held, while
+    still being able to fully print or format it.
+
+    max_group_width and max_group_depth control the formatting of exception
+    groups. The depth refers to the nesting level of the group, and the width
+    refers to the size of a single exception group's exceptions array. The
+    formatted output is truncated when either limit is exceeded.
+
+    Use `from_exception` to create TracebackException instances from exception
+    objects, or the constructor to create TracebackException instances from
+    individual components.
+
+    - :attr:`__cause__` A TracebackException of the original *__cause__*.
+    - :attr:`__context__` A TracebackException of the original *__context__*.
+    - :attr:`exceptions` For exception groups - a list of TracebackException
+      instances for the nested *exceptions*.  ``None`` for other exceptions.
+    - :attr:`__suppress_context__` The *__suppress_context__* value from the
+      original exception.
+    - :attr:`stack` A `StackSummary` representing the traceback.
+    - :attr:`exc_type` The class of the original traceback.
+    - :attr:`filename` For syntax errors - the filename where the error
+      occurred.
+    - :attr:`lineno` For syntax errors - the linenumber where the error
+      occurred.
+    - :attr:`end_lineno` For syntax errors - the end linenumber where the error
+      occurred. Can be `None` if not present.
+    - :attr:`text` For syntax errors - the text where the error
+      occurred.
+    - :attr:`offset` For syntax errors - the offset into the text where the
+      error occurred.
+    - :attr:`end_offset` For syntax errors - the end offset into the text where
+      the error occurred. Can be `None` if not present.
+    - :attr:`msg` For syntax errors - the compiler error message.
+    """
+
+    def __init__(self, exc_type, exc_value, exc_traceback, *, limit=None,
+            lookup_lines=True, capture_locals=False, compact=False,
+            max_group_width=15, max_group_depth=10, _seen=None):
+        # NB: we need to accept exc_traceback, exc_value, exc_traceback to
+        # permit backwards compat with the existing API, otherwise we
+        # need stub thunk objects just to glue it together.
+        # Handle loops in __cause__ or __context__.
+        is_recursive_call = _seen is not None
+        if _seen is None:
+            _seen = set()
+        _seen.add(id(exc_value))
+
+        self.max_group_width = max_group_width
+        self.max_group_depth = max_group_depth
+
+        self.stack = StackSummary._extract_from_extended_frame_gen(
+            _walk_tb_with_full_positions(exc_traceback),
+            limit=limit, lookup_lines=lookup_lines,
+            capture_locals=capture_locals)
+        self.exc_type = exc_type
+        # Capture now to permit freeing resources: only complication is in the
+        # unofficial API _format_final_exc_line
+        self._str = _safe_string(exc_value, 'exception')
+        try:
+            self.__notes__ = getattr(exc_value, '__notes__', None)
+        except Exception as e:
+            self.__notes__ = [
+                f'Ignored error getting __notes__: {_safe_string(e, '__notes__', repr)}']
+
+        if exc_type and issubclass(exc_type, SyntaxError):
+            # Handle SyntaxError's specially
+            self.filename = exc_value.filename
+            lno = exc_value.lineno
+            self.lineno = str(lno) if lno is not None else None
+            end_lno = exc_value.end_lineno
+            self.end_lineno = str(end_lno) if end_lno is not None else None
+            self.text = exc_value.text
+            self.offset = exc_value.offset
+            self.end_offset = exc_value.end_offset
+            self.msg = exc_value.msg
+        elif exc_type and issubclass(exc_type, ImportError) and \
+                getattr(exc_value, "name_from", None) is not None:
+            wrong_name = getattr(exc_value, "name_from", None)
+            suggestion = _compute_suggestion_error(exc_value, exc_traceback, wrong_name)
+            if suggestion:
+                self._str += f". Did you mean: '{suggestion}'?"
+        elif exc_type and issubclass(exc_type, (NameError, AttributeError)) and \
+                getattr(exc_value, "name", None) is not None:
+            wrong_name = getattr(exc_value, "name", None)
+            suggestion = _compute_suggestion_error(exc_value, exc_traceback, wrong_name)
+            if suggestion:
+                self._str += f". Did you mean: '{suggestion}'?"
+            if issubclass(exc_type, NameError):
+                wrong_name = getattr(exc_value, "name", None)
+                if wrong_name is not None and wrong_name in sys.stdlib_module_names:
+                    if suggestion:
+                        self._str += f" Or did you forget to import '{wrong_name}'"
+                    else:
+                        self._str += f". Did you forget to import '{wrong_name}'"
+        if lookup_lines:
+            self._load_lines()
+        self.__suppress_context__ = \
+            exc_value.__suppress_context__ if exc_value is not None else False
+
+        # Convert __cause__ and __context__ to `TracebackExceptions`s, use a
+        # queue to avoid recursion (only the top-level call gets _seen == None)
+        if not is_recursive_call:
+            queue = [(self, exc_value)]
+            while queue:
+                te, e = queue.pop()
+                if (e and e.__cause__ is not None
+                    and id(e.__cause__) not in _seen):
+                    cause = TracebackException(
+                        type(e.__cause__),
+                        e.__cause__,
+                        e.__cause__.__traceback__,
+                        limit=limit,
+                        lookup_lines=lookup_lines,
+                        capture_locals=capture_locals,
+                        max_group_width=max_group_width,
+                        max_group_depth=max_group_depth,
+                        _seen=_seen)
+                else:
+                    cause = None
+
+                if compact:
+                    need_context = (cause is None and
+                                    e is not None and
+                                    not e.__suppress_context__)
+                else:
+                    need_context = True
+                if (e and e.__context__ is not None
+                    and need_context and id(e.__context__) not in _seen):
+                    context = TracebackException(
+                        type(e.__context__),
+                        e.__context__,
+                        e.__context__.__traceback__,
+                        limit=limit,
+                        lookup_lines=lookup_lines,
+                        capture_locals=capture_locals,
+                        max_group_width=max_group_width,
+                        max_group_depth=max_group_depth,
+                        _seen=_seen)
+                else:
+                    context = None
+
+                if e and isinstance(e, BaseExceptionGroup):
+                    exceptions = []
+                    for exc in e.exceptions:
+                        texc = TracebackException(
+                            type(exc),
+                            exc,
+                            exc.__traceback__,
+                            limit=limit,
+                            lookup_lines=lookup_lines,
+                            capture_locals=capture_locals,
+                            max_group_width=max_group_width,
+                            max_group_depth=max_group_depth,
+                            _seen=_seen)
+                        exceptions.append(texc)
+                else:
+                    exceptions = None
+
+                te.__cause__ = cause
+                te.__context__ = context
+                te.exceptions = exceptions
+                if cause:
+                    queue.append((te.__cause__, e.__cause__))
+                if context:
+                    queue.append((te.__context__, e.__context__))
+                if exceptions:
+                    queue.extend(zip(te.exceptions, e.exceptions))
+
+    @classmethod
+    def from_exception(cls, exc, *args, **kwargs):
+        """Create a TracebackException from an exception."""
+        return cls(type(exc), exc, exc.__traceback__, *args, **kwargs)
+
+    def _load_lines(self):
+        """Private API. force all lines in the stack to be loaded."""
+        for frame in self.stack:
+            frame.line
+
+    def __eq__(self, other):
+        if isinstance(other, TracebackException):
+            return self.__dict__ == other.__dict__
+        return NotImplemented
+
+    def __str__(self):
+        return self._str
+
+    def format_exception_only(self):
+        """Format the exception part of the traceback.
+
+        The return value is a generator of strings, each ending in a newline.
+
+        Generator yields the exception message.
+        For :exc:`SyntaxError` exceptions, it
+        also yields (before the exception message)
+        several lines that (when printed)
+        display detailed information about where the syntax error occurred.
+        Following the message, generator also yields
+        all the exception's ``__notes__``.
+        """
+        if self.exc_type is None:
+            yield _format_final_exc_line(None, self._str)
+            return
+
+        stype = self.exc_type.__qualname__
+        smod = self.exc_type.__module__
+        if smod not in ("__main__", "builtins"):
+            if not isinstance(smod, str):
+                smod = "<unknown>"
+            stype = smod + '.' + stype
+
+        if not issubclass(self.exc_type, SyntaxError):
+            yield _format_final_exc_line(stype, self._str)
+        else:
+            yield from self._format_syntax_error(stype)
+
+        if (
+            isinstance(self.__notes__, collections.abc.Sequence)
+            and not isinstance(self.__notes__, (str, bytes))
+        ):
+            for note in self.__notes__:
+                note = _safe_string(note, 'note')
+                yield from [l + '\n' for l in note.split('\n')]
+        elif self.__notes__ is not None:
+            yield "{}\n".format(_safe_string(self.__notes__, '__notes__', func=repr))
+
+    def _format_syntax_error(self, stype):
+        """Format SyntaxError exceptions (internal helper)."""
+        # Show exactly where the problem was found.
+        filename_suffix = ''
+        if self.lineno is not None:
+            yield '  File "{}", line {}\n'.format(
+                self.filename or "<string>", self.lineno)
+        elif self.filename is not None:
+            filename_suffix = ' ({})'.format(self.filename)
+
+        text = self.text
+        if text is not None:
+            # text  = "   foo\n"
+            # rtext = "   foo"
+            # ltext =    "foo"
+            rtext = text.rstrip('\n')
+            ltext = rtext.lstrip(' \n\f')
+            spaces = len(rtext) - len(ltext)
+            yield '    {}\n'.format(ltext)
+
+            if self.offset is not None:
+                offset = self.offset
+                end_offset = self.end_offset if self.end_offset not in {None, 0} else offset
+                if offset == end_offset or end_offset == -1:
+                    end_offset = offset + 1
+
+                # Convert 1-based column offset to 0-based index into stripped text
+                colno = offset - 1 - spaces
+                end_colno = end_offset - 1 - spaces
+                if colno >= 0:
+                    # non-space whitespace (likes tabs) must be kept for alignment
+                    caretspace = ((c if c.isspace() else ' ') for c in ltext[:colno])
+                    yield '    {}{}'.format("".join(caretspace), ('^' * (end_colno - colno) + "\n"))
+        msg = self.msg or "<no detail available>"
+        yield "{}: {}{}\n".format(stype, msg, filename_suffix)
+
+    def format(self, *, chain=True, _ctx=None):
+        """Format the exception.
+
+        If chain is not *True*, *__cause__* and *__context__* will not be formatted.
+
+        The return value is a generator of strings, each ending in a newline and
+        some containing internal newlines. `print_exception` is a wrapper around
+        this method which just prints the lines to a file.
+
+        The message indicating which exception occurred is always the last
+        string in the output.
+        """
+
+        if _ctx is None:
+            _ctx = _ExceptionPrintContext()
+
+        output = []
+        exc = self
+        if chain:
+            while exc:
+                if exc.__cause__ is not None:
+                    chained_msg = _cause_message
+                    chained_exc = exc.__cause__
+                elif (exc.__context__  is not None and
+                      not exc.__suppress_context__):
+                    chained_msg = _context_message
+                    chained_exc = exc.__context__
+                else:
+                    chained_msg = None
+                    chained_exc = None
+
+                output.append((chained_msg, exc))
+                exc = chained_exc
+        else:
+            output.append((None, exc))
+
+        for msg, exc in reversed(output):
+            if msg is not None:
+                yield from _ctx.emit(msg)
+            if exc.exceptions is None:
+                if exc.stack:
+                    yield from _ctx.emit('Traceback (most recent call last):\n')
+                    yield from _ctx.emit(exc.stack.format())
+                yield from _ctx.emit(exc.format_exception_only())
+            elif _ctx.exception_group_depth > self.max_group_depth:
+                # exception group, but depth exceeds limit
+                yield from _ctx.emit(
+                    f"... (max_group_depth is {self.max_group_depth})\n")
+            else:
+                # format exception group
+                is_toplevel = (_ctx.exception_group_depth == 0)
+                if is_toplevel:
+                    _ctx.exception_group_depth += 1
+
+                if exc.stack:
+                    yield from _ctx.emit(
+                        'Exception Group Traceback (most recent call last):\n',
+                        margin_char = '+' if is_toplevel else None)
+                    yield from _ctx.emit(exc.stack.format())
+
+                yield from _ctx.emit(exc.format_exception_only())
+                num_excs = len(exc.exceptions)
+                if num_excs <= self.max_group_width:
+                    n = num_excs
+                else:
+                    n = self.max_group_width + 1
+                _ctx.need_close = False
+                for i in range(n):
+                    last_exc = (i == n-1)
+                    if last_exc:
+                        # The closing frame may be added by a recursive call
+                        _ctx.need_close = True
+
+                    if self.max_group_width is not None:
+                        truncated = (i >= self.max_group_width)
+                    else:
+                        truncated = False
+                    title = f'{i+1}' if not truncated else '...'
+                    yield (_ctx.indent() +
+                           ('+-' if i==0 else '  ') +
+                           f'+---------------- {title} ----------------\n')
+                    _ctx.exception_group_depth += 1
+                    if not truncated:
+                        yield from exc.exceptions[i].format(chain=chain, _ctx=_ctx)
+                    else:
+                        remaining = num_excs - self.max_group_width
+                        plural = 's' if remaining > 1 else ''
+                        yield from _ctx.emit(
+                            f"and {remaining} more exception{plural}\n")
+
+                    if last_exc and _ctx.need_close:
+                        yield (_ctx.indent() +
+                               "+------------------------------------\n")
+                        _ctx.need_close = False
+                    _ctx.exception_group_depth -= 1
+
+                if is_toplevel:
+                    assert _ctx.exception_group_depth == 1
+                    _ctx.exception_group_depth = 0
+
+
+    def print(self, *, file=None, chain=True):
+        """Print the result of self.format(chain=chain) to 'file'."""
+        if file is None:
+            file = sys.stderr
+        for line in self.format(chain=chain):
+            print(line, file=file, end="")
+
+
+_MAX_CANDIDATE_ITEMS = 750
+_MAX_STRING_SIZE = 40
+_MOVE_COST = 2
+_CASE_COST = 1
+
+
+def _substitution_cost(ch_a, ch_b):
+    if ch_a == ch_b:
+        return 0
+    if ch_a.lower() == ch_b.lower():
+        return _CASE_COST
+    return _MOVE_COST
+
+
+def _compute_suggestion_error(exc_value, tb, wrong_name):
+    if wrong_name is None or not isinstance(wrong_name, str):
+        return None
+    if isinstance(exc_value, AttributeError):
+        obj = exc_value.obj
+        try:
+            d = dir(obj)
+        except Exception:
+            return None
+    elif isinstance(exc_value, ImportError):
+        try:
+            mod = __import__(exc_value.name)
+            d = dir(mod)
+        except Exception:
+            return None
+    else:
+        assert isinstance(exc_value, NameError)
+        # find most recent frame
+        if tb is None:
+            return None
+        while tb.tb_next is not None:
+            tb = tb.tb_next
+        frame = tb.tb_frame
+        d = (
+            list(frame.f_locals)
+            + list(frame.f_globals)
+            + list(frame.f_builtins)
+        )
+
+        # Check first if we are in a method and the instance
+        # has the wrong name as attribute
+        if 'self' in frame.f_locals:
+            self = frame.f_locals['self']
+            if hasattr(self, wrong_name):
+                return f"self.{wrong_name}"
+
+    # Compute closest match
+
+    if len(d) > _MAX_CANDIDATE_ITEMS:
+        return None
+    wrong_name_len = len(wrong_name)
+    if wrong_name_len > _MAX_STRING_SIZE:
+        return None
+    best_distance = wrong_name_len
+    suggestion = None
+    for possible_name in d:
+        if possible_name == wrong_name:
+            # A missing attribute is "found". Don't suggest it (see GH-88821).
+            continue
+        # No more than 1/3 of the involved characters should need changed.
+        max_distance = (len(possible_name) + wrong_name_len + 3) * _MOVE_COST // 6
+        # Don't take matches we've already beaten.
+        max_distance = min(max_distance, best_distance - 1)
+        current_distance = _levenshtein_distance(wrong_name, possible_name, max_distance)
+        if current_distance > max_distance:
+            continue
+        if not suggestion or current_distance < best_distance:
+            suggestion = possible_name
+            best_distance = current_distance
+    return suggestion
+
+
+def _levenshtein_distance(a, b, max_cost):
+    # A Python implementation of Python/suggestions.c:levenshtein_distance.
+
+    # Both strings are the same
+    if a == b:
+        return 0
+
+    # Trim away common affixes
+    pre = 0
+    while a[pre:] and b[pre:] and a[pre] == b[pre]:
+        pre += 1
+    a = a[pre:]
+    b = b[pre:]
+    post = 0
+    while a[:post or None] and b[:post or None] and a[post-1] == b[post-1]:
+        post -= 1
+    a = a[:post or None]
+    b = b[:post or None]
+    if not a or not b:
+        return _MOVE_COST * (len(a) + len(b))
+    if len(a) > _MAX_STRING_SIZE or len(b) > _MAX_STRING_SIZE:
+        return max_cost + 1
+
+    # Prefer shorter buffer
+    if len(b) < len(a):
+        a, b = b, a
+
+    # Quick fail when a match is impossible
+    if (len(b) - len(a)) * _MOVE_COST > max_cost:
+        return max_cost + 1
+
+    # Instead of producing the whole traditional len(a)-by-len(b)
+    # matrix, we can update just one row in place.
+    # Initialize the buffer row
+    row = list(range(_MOVE_COST, _MOVE_COST * (len(a) + 1), _MOVE_COST))
+
+    result = 0
+    for bindex in range(len(b)):
+        bchar = b[bindex]
+        distance = result = bindex * _MOVE_COST
+        minimum = sys.maxsize
+        for index in range(len(a)):
+            # 1) Previous distance in this row is cost(b[:b_index], a[:index])
+            substitute = distance + _substitution_cost(bchar, a[index])
+            # 2) cost(b[:b_index], a[:index+1]) from previous row
+            distance = row[index]
+            # 3) existing result is cost(b[:b_index+1], a[index])
+
+            insert_delete = min(result, distance) + _MOVE_COST
+            result = min(insert_delete, substitute)
+
+            # cost(b[:b_index+1], a[:index+1])
+            row[index] = result
+            if result < minimum:
+                minimum = result
+        if minimum > max_cost:
+            # Everything in this row is too big, so bail early.
+            return max_cost + 1
+    return result