mirror of
https://github.com/python/cpython.git
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bf36409e2a
added message attribute compared to the previous version of Exception. It is also a new-style class, making all exceptions now new-style. KeyboardInterrupt and SystemExit inherit from BaseException directly. String exceptions now raise DeprecationWarning. Applies patch 1104669, and closes bugs 1012952 and 518846.
299 lines
10 KiB
Python
299 lines
10 KiB
Python
"""Extract, format and print information about Python stack traces."""
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import linecache
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import sys
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import types
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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', 'tb_lineno']
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def _print(file, str='', terminator='\n'):
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file.write(str+terminator)
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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 filename, lineno, name, line in extracted_list:
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_print(file,
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' File "%s", line %d, in %s' % (filename,lineno,name))
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if line:
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_print(file, ' %s' % line.strip())
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def format_list(extracted_list):
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"""Format a list of traceback entry tuples for printing.
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Given a list of tuples as returned by extract_tb() or
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extract_stack(), return a list of strings ready 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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list = []
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for filename, lineno, name, line in extracted_list:
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item = ' File "%s", line %d, in %s\n' % (filename,lineno,name)
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if line:
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item = item + ' %s\n' % line.strip()
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list.append(item)
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return list
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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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if file is None:
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file = sys.stderr
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if limit is None:
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if hasattr(sys, 'tracebacklimit'):
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limit = sys.tracebacklimit
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n = 0
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while tb is not None and (limit is None or n < limit):
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f = tb.tb_frame
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lineno = tb.tb_lineno
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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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_print(file,
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' File "%s", line %d, in %s' % (filename,lineno,name))
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linecache.checkcache(filename)
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line = linecache.getline(filename, lineno)
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if line: _print(file, ' ' + line.strip())
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tb = tb.tb_next
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n = n+1
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def format_tb(tb, limit = None):
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"""A shorthand for 'format_list(extract_stack(f, limit))."""
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return format_list(extract_tb(tb, limit))
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def extract_tb(tb, limit = None):
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"""Return list of up to limit 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 quadruple (filename, line
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number, function name, text) representing the information that is
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usually printed for a stack trace. The text is a string with
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leading and trailing whitespace stripped; if the source is not
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available it is None.
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"""
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if limit is None:
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if hasattr(sys, 'tracebacklimit'):
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limit = sys.tracebacklimit
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list = []
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n = 0
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while tb is not None and (limit is None or n < limit):
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f = tb.tb_frame
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lineno = tb.tb_lineno
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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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linecache.checkcache(filename)
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line = linecache.getline(filename, lineno)
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if line: line = line.strip()
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else: line = None
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list.append((filename, lineno, name, line))
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tb = tb.tb_next
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n = n+1
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return list
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def print_exception(etype, value, tb, limit=None, file=None):
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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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if file is None:
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file = sys.stderr
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if tb:
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_print(file, 'Traceback (most recent call last):')
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print_tb(tb, limit, file)
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lines = format_exception_only(etype, value)
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for line in lines[:-1]:
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_print(file, line, ' ')
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_print(file, lines[-1], '')
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def format_exception(etype, value, tb, limit = None):
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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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if tb:
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list = ['Traceback (most recent call last):\n']
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list = list + format_tb(tb, limit)
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else:
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list = []
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list = list + format_exception_only(etype, value)
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return list
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def format_exception_only(etype, value):
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"""Format the exception part of a traceback.
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The arguments are the exception type and value such as given by
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sys.last_type and sys.last_value. The return value is a list of
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strings, each ending in a newline. Normally, the list contains a
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single string; however, for SyntaxError exceptions, it contains
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several lines that (when printed) display detailed information
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about where the syntax error occurred. The message indicating
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which exception occurred is the always last string in the list.
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"""
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list = []
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if (type(etype) == types.ClassType
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or (isinstance(etype, type) and issubclass(etype, Exception))):
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stype = etype.__name__
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else:
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stype = etype
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if value is None:
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list.append(str(stype) + '\n')
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else:
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if etype is SyntaxError:
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try:
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msg, (filename, lineno, offset, line) = value
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except:
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pass
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else:
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if not filename: filename = "<string>"
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list.append(' File "%s", line %d\n' %
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(filename, lineno))
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if line is not None:
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i = 0
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while i < len(line) and line[i].isspace():
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i = i+1
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list.append(' %s\n' % line.strip())
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if offset is not None:
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s = ' '
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for c in line[i:offset-1]:
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if c.isspace():
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s = s + c
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else:
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s = s + ' '
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list.append('%s^\n' % s)
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value = msg
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s = _some_str(value)
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if s:
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list.append('%s: %s\n' % (str(stype), s))
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else:
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list.append('%s\n' % str(stype))
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return list
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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 '<unprintable %s object>' % type(value).__name__
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def print_exc(limit=None, file=None):
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"""Shorthand for 'print_exception(sys.exc_type, sys.exc_value, sys.exc_traceback, limit, file)'.
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(In fact, it uses sys.exc_info() to retrieve the same information
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in a thread-safe way.)"""
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if file is None:
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file = sys.stderr
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try:
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etype, value, tb = sys.exc_info()
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print_exception(etype, value, tb, limit, file)
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finally:
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etype = value = tb = None
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def format_exc(limit=None):
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"""Like print_exc() but return a string."""
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try:
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etype, value, tb = sys.exc_info()
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return ''.join(format_exception(etype, value, tb, limit))
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finally:
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etype = value = tb = None
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def print_last(limit=None, file=None):
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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 file is None:
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file = sys.stderr
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print_exception(sys.last_type, sys.last_value, sys.last_traceback,
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limit, file)
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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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try:
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raise ZeroDivisionError
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except ZeroDivisionError:
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f = sys.exc_info()[2].tb_frame.f_back
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print_list(extract_stack(f, limit), 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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try:
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raise ZeroDivisionError
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except ZeroDivisionError:
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f = sys.exc_info()[2].tb_frame.f_back
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return format_list(extract_stack(f, 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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try:
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raise ZeroDivisionError
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except ZeroDivisionError:
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f = sys.exc_info()[2].tb_frame.f_back
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if limit is None:
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if hasattr(sys, 'tracebacklimit'):
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limit = sys.tracebacklimit
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list = []
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n = 0
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while f is not None and (limit is None or n < limit):
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lineno = f.f_lineno
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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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linecache.checkcache(filename)
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line = linecache.getline(filename, lineno)
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if line: line = line.strip()
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else: line = None
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list.append((filename, lineno, name, line))
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f = f.f_back
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n = n+1
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list.reverse()
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return list
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def tb_lineno(tb):
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"""Calculate correct line number of traceback given in tb.
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Obsolete in 2.3.
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"""
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return tb.tb_lineno
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