mirror of https://github.com/python/cpython
831 lines
31 KiB
Python
831 lines
31 KiB
Python
"""Extract, format and print information about Python stack traces."""
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import collections
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import itertools
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import linecache
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import sys
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from contextlib import suppress
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__all__ = ['extract_stack', 'extract_tb', 'format_exception',
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'format_exception_only', 'format_list', 'format_stack',
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'format_tb', 'print_exc', 'format_exc', 'print_exception',
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'print_last', 'print_stack', 'print_tb', 'clear_frames',
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'FrameSummary', 'StackSummary', 'TracebackException',
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'walk_stack', 'walk_tb']
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#
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# Formatting and printing lists of traceback lines.
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#
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def print_list(extracted_list, file=None):
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"""Print the list of tuples as returned by extract_tb() or
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extract_stack() as a formatted stack trace to the given file."""
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if file is None:
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file = sys.stderr
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for item in StackSummary.from_list(extracted_list).format():
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print(item, file=file, end="")
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def format_list(extracted_list):
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"""Format a list of tuples or FrameSummary objects for printing.
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Given a list of tuples or FrameSummary objects as returned by
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extract_tb() or extract_stack(), return a list of strings ready
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for printing.
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Each string in the resulting list corresponds to the item with the
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same index in the argument list. Each string ends in a newline;
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the strings may contain internal newlines as well, for those items
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whose source text line is not None.
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"""
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return StackSummary.from_list(extracted_list).format()
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#
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# Printing and Extracting Tracebacks.
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#
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def print_tb(tb, limit=None, file=None):
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"""Print up to 'limit' stack trace entries from the traceback 'tb'.
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If 'limit' is omitted or None, all entries are printed. If 'file'
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is omitted or None, the output goes to sys.stderr; otherwise
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'file' should be an open file or file-like object with a write()
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method.
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"""
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print_list(extract_tb(tb, limit=limit), file=file)
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def format_tb(tb, limit=None):
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"""A shorthand for 'format_list(extract_tb(tb, limit))'."""
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return extract_tb(tb, limit=limit).format()
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def extract_tb(tb, limit=None):
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"""
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Return a StackSummary object representing a list of
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pre-processed entries from traceback.
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This is useful for alternate formatting of stack traces. If
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'limit' is omitted or None, all entries are extracted. A
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pre-processed stack trace entry is a FrameSummary object
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containing attributes filename, lineno, name, and line
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representing the information that is usually printed for a stack
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trace. The line is a string with leading and trailing
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whitespace stripped; if the source is not available it is None.
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"""
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return StackSummary._extract_from_extended_frame_gen(
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_walk_tb_with_full_positions(tb), limit=limit)
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#
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# Exception formatting and output.
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#
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_cause_message = (
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"\nThe above exception was the direct cause "
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"of the following exception:\n\n")
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_context_message = (
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"\nDuring handling of the above exception, "
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"another exception occurred:\n\n")
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class _Sentinel:
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def __repr__(self):
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return "<implicit>"
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_sentinel = _Sentinel()
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def _parse_value_tb(exc, value, tb):
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if (value is _sentinel) != (tb is _sentinel):
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raise ValueError("Both or neither of value and tb must be given")
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if value is tb is _sentinel:
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if exc is not None:
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return exc, exc.__traceback__
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else:
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return None, None
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return value, tb
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def print_exception(exc, /, value=_sentinel, tb=_sentinel, limit=None, \
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file=None, chain=True):
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"""Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
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This differs from print_tb() in the following ways: (1) if
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traceback is not None, it prints a header "Traceback (most recent
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call last):"; (2) it prints the exception type and value after the
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stack trace; (3) if type is SyntaxError and value has the
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appropriate format, it prints the line where the syntax error
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occurred with a caret on the next line indicating the approximate
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position of the error.
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"""
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value, tb = _parse_value_tb(exc, value, tb)
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te = TracebackException(type(value), value, tb, limit=limit, compact=True)
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te.print(file=file, chain=chain)
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def format_exception(exc, /, value=_sentinel, tb=_sentinel, limit=None, \
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chain=True):
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"""Format a stack trace and the exception information.
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The arguments have the same meaning as the corresponding arguments
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to print_exception(). The return value is a list of strings, each
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ending in a newline and some containing internal newlines. When
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these lines are concatenated and printed, exactly the same text is
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printed as does print_exception().
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"""
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value, tb = _parse_value_tb(exc, value, tb)
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te = TracebackException(type(value), value, tb, limit=limit, compact=True)
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return list(te.format(chain=chain))
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def format_exception_only(exc, /, value=_sentinel):
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"""Format the exception part of a traceback.
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The return value is a list of strings, each ending in a newline.
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Normally, the list contains a single string; however, for
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SyntaxError exceptions, it contains several lines that (when
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printed) display detailed information about where the syntax
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error occurred.
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The message indicating which exception occurred is always the last
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string in the list.
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"""
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if value is _sentinel:
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value = exc
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te = TracebackException(type(value), value, None, compact=True)
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return list(te.format_exception_only())
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# -- not official API but folk probably use these two functions.
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def _format_final_exc_line(etype, value):
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valuestr = _some_str(value)
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if value is None or not valuestr:
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line = "%s\n" % etype
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else:
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line = "%s: %s\n" % (etype, valuestr)
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return line
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def _some_str(value):
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try:
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return str(value)
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except:
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return '<exception str() failed>'
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# --
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def print_exc(limit=None, file=None, chain=True):
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"""Shorthand for 'print_exception(*sys.exc_info(), limit, file)'."""
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print_exception(*sys.exc_info(), limit=limit, file=file, chain=chain)
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def format_exc(limit=None, chain=True):
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"""Like print_exc() but return a string."""
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return "".join(format_exception(*sys.exc_info(), limit=limit, chain=chain))
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def print_last(limit=None, file=None, chain=True):
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"""This is a shorthand for 'print_exception(sys.last_type,
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sys.last_value, sys.last_traceback, limit, file)'."""
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if not hasattr(sys, "last_type"):
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raise ValueError("no last exception")
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print_exception(sys.last_type, sys.last_value, sys.last_traceback,
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limit, file, chain)
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#
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# Printing and Extracting Stacks.
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#
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def print_stack(f=None, limit=None, file=None):
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"""Print a stack trace from its invocation point.
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The optional 'f' argument can be used to specify an alternate
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stack frame at which to start. The optional 'limit' and 'file'
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arguments have the same meaning as for print_exception().
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"""
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if f is None:
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f = sys._getframe().f_back
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print_list(extract_stack(f, limit=limit), file=file)
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def format_stack(f=None, limit=None):
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"""Shorthand for 'format_list(extract_stack(f, limit))'."""
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if f is None:
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f = sys._getframe().f_back
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return format_list(extract_stack(f, limit=limit))
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def extract_stack(f=None, limit=None):
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"""Extract the raw traceback from the current stack frame.
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The return value has the same format as for extract_tb(). The
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optional 'f' and 'limit' arguments have the same meaning as for
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print_stack(). Each item in the list is a quadruple (filename,
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line number, function name, text), and the entries are in order
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from oldest to newest stack frame.
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"""
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if f is None:
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f = sys._getframe().f_back
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stack = StackSummary.extract(walk_stack(f), limit=limit)
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stack.reverse()
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return stack
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def clear_frames(tb):
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"Clear all references to local variables in the frames of a traceback."
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while tb is not None:
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try:
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tb.tb_frame.clear()
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except RuntimeError:
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# Ignore the exception raised if the frame is still executing.
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pass
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tb = tb.tb_next
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class FrameSummary:
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"""Information about a single frame from a traceback.
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- :attr:`filename` The filename for the frame.
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- :attr:`lineno` The line within filename for the frame that was
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active when the frame was captured.
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- :attr:`name` The name of the function or method that was executing
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when the frame was captured.
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- :attr:`line` The text from the linecache module for the
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of code that was running when the frame was captured.
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- :attr:`locals` Either None if locals were not supplied, or a dict
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mapping the name to the repr() of the variable.
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"""
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__slots__ = ('filename', 'lineno', 'end_lineno', 'colno', 'end_colno',
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'name', '_line', 'locals')
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def __init__(self, filename, lineno, name, *, lookup_line=True,
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locals=None, line=None,
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end_lineno=None, colno=None, end_colno=None):
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"""Construct a FrameSummary.
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:param lookup_line: If True, `linecache` is consulted for the source
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code line. Otherwise, the line will be looked up when first needed.
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:param locals: If supplied the frame locals, which will be captured as
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object representations.
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:param line: If provided, use this instead of looking up the line in
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the linecache.
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"""
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self.filename = filename
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self.lineno = lineno
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self.name = name
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self._line = line
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if lookup_line:
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self.line
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self.locals = {k: repr(v) for k, v in locals.items()} if locals else None
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self.end_lineno = end_lineno
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self.colno = colno
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self.end_colno = end_colno
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def __eq__(self, other):
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if isinstance(other, FrameSummary):
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return (self.filename == other.filename and
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self.lineno == other.lineno and
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self.name == other.name and
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self.locals == other.locals)
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if isinstance(other, tuple):
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return (self.filename, self.lineno, self.name, self.line) == other
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return NotImplemented
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def __getitem__(self, pos):
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return (self.filename, self.lineno, self.name, self.line)[pos]
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def __iter__(self):
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return iter([self.filename, self.lineno, self.name, self.line])
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def __repr__(self):
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return "<FrameSummary file {filename}, line {lineno} in {name}>".format(
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filename=self.filename, lineno=self.lineno, name=self.name)
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def __len__(self):
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return 4
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@property
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def _original_line(self):
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# Returns the line as-is from the source, without modifying whitespace.
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self.line
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return self._line
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@property
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def line(self):
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if self._line is None:
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if self.lineno is None:
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return None
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self._line = linecache.getline(self.filename, self.lineno)
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return self._line.strip()
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def walk_stack(f):
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"""Walk a stack yielding the frame and line number for each frame.
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This will follow f.f_back from the given frame. If no frame is given, the
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current stack is used. Usually used with StackSummary.extract.
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"""
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if f is None:
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f = sys._getframe().f_back.f_back.f_back.f_back
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while f is not None:
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yield f, f.f_lineno
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f = f.f_back
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def walk_tb(tb):
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"""Walk a traceback yielding the frame and line number for each frame.
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This will follow tb.tb_next (and thus is in the opposite order to
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walk_stack). Usually used with StackSummary.extract.
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"""
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while tb is not None:
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yield tb.tb_frame, tb.tb_lineno
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tb = tb.tb_next
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def _walk_tb_with_full_positions(tb):
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# Internal version of walk_tb that yields full code positions including
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# end line and column information.
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while tb is not None:
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positions = _get_code_position(tb.tb_frame.f_code, tb.tb_lasti)
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# Yield tb_lineno when co_positions does not have a line number to
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# maintain behavior with walk_tb.
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if positions[0] is None:
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yield tb.tb_frame, (tb.tb_lineno, ) + positions[1:]
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else:
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yield tb.tb_frame, positions
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tb = tb.tb_next
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def _get_code_position(code, instruction_index):
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if instruction_index < 0:
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return (None, None, None, None)
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positions_gen = code.co_positions()
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return next(itertools.islice(positions_gen, instruction_index // 2, None))
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_RECURSIVE_CUTOFF = 3 # Also hardcoded in traceback.c.
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class StackSummary(list):
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"""A list of FrameSummary objects, representing a stack of frames."""
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@classmethod
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def extract(klass, frame_gen, *, limit=None, lookup_lines=True,
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capture_locals=False):
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"""Create a StackSummary from a traceback or stack object.
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:param frame_gen: A generator that yields (frame, lineno) tuples
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whose summaries are to be included in the stack.
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:param limit: None to include all frames or the number of frames to
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include.
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:param lookup_lines: If True, lookup lines for each frame immediately,
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otherwise lookup is deferred until the frame is rendered.
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:param capture_locals: If True, the local variables from each frame will
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be captured as object representations into the FrameSummary.
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"""
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def extended_frame_gen():
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for f, lineno in frame_gen:
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yield f, (lineno, None, None, None)
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return klass._extract_from_extended_frame_gen(
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extended_frame_gen(), limit=limit, lookup_lines=lookup_lines,
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capture_locals=capture_locals)
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@classmethod
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def _extract_from_extended_frame_gen(klass, frame_gen, *, limit=None,
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lookup_lines=True, capture_locals=False):
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# Same as extract but operates on a frame generator that yields
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# (frame, (lineno, end_lineno, colno, end_colno)) in the stack.
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# Only lineno is required, the remaining fields can be None if the
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# information is not available.
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if limit is None:
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limit = getattr(sys, 'tracebacklimit', None)
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if limit is not None and limit < 0:
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limit = 0
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if limit is not None:
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if limit >= 0:
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frame_gen = itertools.islice(frame_gen, limit)
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else:
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frame_gen = collections.deque(frame_gen, maxlen=-limit)
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result = klass()
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fnames = set()
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for f, (lineno, end_lineno, colno, end_colno) in frame_gen:
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co = f.f_code
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filename = co.co_filename
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name = co.co_name
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fnames.add(filename)
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linecache.lazycache(filename, f.f_globals)
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# Must defer line lookups until we have called checkcache.
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if capture_locals:
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f_locals = f.f_locals
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else:
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f_locals = None
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result.append(FrameSummary(
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filename, lineno, name, lookup_line=False, locals=f_locals,
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end_lineno=end_lineno, colno=colno, end_colno=end_colno))
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for filename in fnames:
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linecache.checkcache(filename)
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# If immediate lookup was desired, trigger lookups now.
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if lookup_lines:
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for f in result:
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f.line
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return result
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@classmethod
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def from_list(klass, a_list):
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"""
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Create a StackSummary object from a supplied list of
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FrameSummary objects or old-style list of tuples.
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"""
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# While doing a fast-path check for isinstance(a_list, StackSummary) is
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# appealing, idlelib.run.cleanup_traceback and other similar code may
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# break this by making arbitrary frames plain tuples, so we need to
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# check on a frame by frame basis.
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result = StackSummary()
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for frame in a_list:
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if isinstance(frame, FrameSummary):
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result.append(frame)
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else:
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filename, lineno, name, line = frame
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result.append(FrameSummary(filename, lineno, name, line=line))
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return result
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def format_frame_summary(self, frame_summary):
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"""Format the lines for a single FrameSummary.
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Returns a string representing one frame involved in the stack. This
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gets called for every frame to be printed in the stack summary.
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"""
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row = []
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row.append(' File "{}", line {}, in {}\n'.format(
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frame_summary.filename, frame_summary.lineno, frame_summary.name))
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if frame_summary.line:
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row.append(' {}\n'.format(frame_summary.line.strip()))
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orig_line_len = len(frame_summary._original_line)
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frame_line_len = len(frame_summary.line.lstrip())
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stripped_characters = orig_line_len - frame_line_len
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if (
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frame_summary.colno is not None
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and frame_summary.end_colno is not None
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):
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colno = _byte_offset_to_character_offset(
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frame_summary._original_line, frame_summary.colno)
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end_colno = _byte_offset_to_character_offset(
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frame_summary._original_line, frame_summary.end_colno)
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anchors = None
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if frame_summary.lineno == frame_summary.end_lineno:
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with suppress(Exception):
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anchors = _extract_caret_anchors_from_line_segment(
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frame_summary._original_line[colno - 1:end_colno - 1]
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)
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else:
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end_colno = stripped_characters + len(frame_summary.line.strip())
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row.append(' ')
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row.append(' ' * (colno - stripped_characters))
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if anchors:
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row.append(anchors.primary_char * (anchors.left_end_offset))
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row.append(anchors.secondary_char * (anchors.right_start_offset - anchors.left_end_offset))
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row.append(anchors.primary_char * (end_colno - colno - anchors.right_start_offset))
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else:
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row.append('^' * (end_colno - colno))
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row.append('\n')
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if frame_summary.locals:
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for name, value in sorted(frame_summary.locals.items()):
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row.append(' {name} = {value}\n'.format(name=name, value=value))
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|
|
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')
|
|
if offset > len(as_utf8):
|
|
offset = len(as_utf8)
|
|
|
|
return len(as_utf8[:offset + 1].decode("utf-8"))
|
|
|
|
|
|
_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
|
|
|
|
statement = tree.body[0]
|
|
match statement:
|
|
case ast.Expr(expr):
|
|
match expr:
|
|
case ast.BinOp():
|
|
operator_str = segment[expr.left.end_col_offset:expr.right.col_offset]
|
|
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
|
|
return _Anchors(left_anchor, right_anchor)
|
|
case ast.Subscript():
|
|
return _Anchors(expr.value.end_col_offset, expr.slice.end_col_offset + 1)
|
|
|
|
return None
|
|
|
|
|
|
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.
|
|
|
|
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:`__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:`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:`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,
|
|
_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))
|
|
|
|
# TODO: locals.
|
|
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 = _some_str(exc_value)
|
|
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
|
|
self.text = exc_value.text
|
|
self.offset = exc_value.offset
|
|
self.msg = exc_value.msg
|
|
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,
|
|
_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,
|
|
_seen=_seen)
|
|
else:
|
|
context = None
|
|
te.__cause__ = cause
|
|
te.__context__ = context
|
|
if cause:
|
|
queue.append((te.__cause__, e.__cause__))
|
|
if context:
|
|
queue.append((te.__context__, e.__context__))
|
|
|
|
@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.
|
|
|
|
Normally, the generator emits a single string; however, for
|
|
SyntaxError exceptions, it emits several lines that (when
|
|
printed) display detailed information about where the syntax
|
|
error occurred.
|
|
|
|
The message indicating which exception occurred is always the last
|
|
string in the output.
|
|
"""
|
|
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"):
|
|
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)
|
|
|
|
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)
|
|
# Convert 1-based column offset to 0-based index into stripped text
|
|
caret = (self.offset or 0) - 1 - spaces
|
|
if caret >= 0:
|
|
# non-space whitespace (likes tabs) must be kept for alignment
|
|
caretspace = ((c if c.isspace() else ' ') for c in ltext[:caret])
|
|
yield ' {}^\n'.format(''.join(caretspace))
|
|
msg = self.msg or "<no detail available>"
|
|
yield "{}: {}{}\n".format(stype, msg, filename_suffix)
|
|
|
|
def format(self, *, chain=True):
|
|
"""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.
|
|
"""
|
|
|
|
output = []
|
|
exc = self
|
|
while exc:
|
|
if chain:
|
|
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))
|
|
exc = None
|
|
|
|
for msg, exc in reversed(output):
|
|
if msg is not None:
|
|
yield msg
|
|
if exc.stack:
|
|
yield 'Traceback (most recent call last):\n'
|
|
yield from exc.stack.format()
|
|
yield from exc.format_exception_only()
|
|
|
|
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="")
|