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Guido van Rossume7b146f2000-02-04 15:28:42 +00001"""Extract, format and print information about Python stack traces."""
Guido van Rossum526beed1994-07-01 15:36:46 +00002
3import linecache
Guido van Rossum526beed1994-07-01 15:36:46 +00004import sys
Guido van Rossumc7acf2a1995-02-27 13:15:45 +00005import types
Guido van Rossum526beed1994-07-01 15:36:46 +00006
Skip Montanaro40fc1602001-03-01 04:27:19 +00007__all__ = ['extract_stack', 'extract_tb', 'format_exception',
8 'format_exception_only', 'format_list', 'format_stack',
9 'format_tb', 'print_exc', 'print_exception', 'print_last',
10 'print_stack', 'print_tb', 'tb_lineno']
11
Guido van Rossum194e20a1995-09-20 20:31:51 +000012def _print(file, str='', terminator='\n'):
Tim Petersb90f89a2001-01-15 03:26:36 +000013 file.write(str+terminator)
Guido van Rossumdcc057a1996-08-12 23:18:13 +000014
15
16def print_list(extracted_list, file=None):
Tim Petersb90f89a2001-01-15 03:26:36 +000017 """Print the list of tuples as returned by extract_tb() or
18 extract_stack() as a formatted stack trace to the given file."""
19 if not file:
20 file = sys.stderr
21 for filename, lineno, name, line in extracted_list:
22 _print(file,
23 ' File "%s", line %d, in %s' % (filename,lineno,name))
24 if line:
Eric S. Raymondec3bbde2001-02-09 09:39:08 +000025 _print(file, ' %s' % line.strip())
Guido van Rossumdcc057a1996-08-12 23:18:13 +000026
27def format_list(extracted_list):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +000028 """Format a list of traceback entry tuples for printing.
29
30 Given a list of tuples as returned by extract_tb() or
Tim Petersb90f89a2001-01-15 03:26:36 +000031 extract_stack(), return a list of strings ready for printing.
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +000032 Each string in the resulting list corresponds to the item with the
33 same index in the argument list. Each string ends in a newline;
34 the strings may contain internal newlines as well, for those items
35 whose source text line is not None.
36 """
Tim Petersb90f89a2001-01-15 03:26:36 +000037 list = []
38 for filename, lineno, name, line in extracted_list:
39 item = ' File "%s", line %d, in %s\n' % (filename,lineno,name)
40 if line:
Eric S. Raymondec3bbde2001-02-09 09:39:08 +000041 item = item + ' %s\n' % line.strip()
Tim Petersb90f89a2001-01-15 03:26:36 +000042 list.append(item)
43 return list
44
Guido van Rossum194e20a1995-09-20 20:31:51 +000045
46def print_tb(tb, limit=None, file=None):
Tim Petersb90f89a2001-01-15 03:26:36 +000047 """Print up to 'limit' stack trace entries from the traceback 'tb'.
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +000048
49 If 'limit' is omitted or None, all entries are printed. If 'file'
50 is omitted or None, the output goes to sys.stderr; otherwise
51 'file' should be an open file or file-like object with a write()
52 method.
53 """
Tim Petersb90f89a2001-01-15 03:26:36 +000054 if not file:
55 file = sys.stderr
56 if limit is None:
57 if hasattr(sys, 'tracebacklimit'):
58 limit = sys.tracebacklimit
59 n = 0
60 while tb is not None and (limit is None or n < limit):
61 f = tb.tb_frame
62 lineno = tb_lineno(tb)
63 co = f.f_code
64 filename = co.co_filename
65 name = co.co_name
66 _print(file,
67 ' File "%s", line %d, in %s' % (filename,lineno,name))
68 line = linecache.getline(filename, lineno)
Eric S. Raymondec3bbde2001-02-09 09:39:08 +000069 if line: _print(file, ' ' + line.strip())
Tim Petersb90f89a2001-01-15 03:26:36 +000070 tb = tb.tb_next
71 n = n+1
Guido van Rossum526beed1994-07-01 15:36:46 +000072
Guido van Rossum28e99fe1995-08-04 04:30:30 +000073def format_tb(tb, limit = None):
Tim Petersb90f89a2001-01-15 03:26:36 +000074 """A shorthand for 'format_list(extract_stack(f, limit))."""
75 return format_list(extract_tb(tb, limit))
Guido van Rossum28e99fe1995-08-04 04:30:30 +000076
Guido van Rossum526beed1994-07-01 15:36:46 +000077def extract_tb(tb, limit = None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +000078 """Return list of up to limit pre-processed entries from traceback.
79
80 This is useful for alternate formatting of stack traces. If
81 'limit' is omitted or None, all entries are extracted. A
82 pre-processed stack trace entry is a quadruple (filename, line
83 number, function name, text) representing the information that is
84 usually printed for a stack trace. The text is a string with
85 leading and trailing whitespace stripped; if the source is not
86 available it is None.
87 """
Tim Petersb90f89a2001-01-15 03:26:36 +000088 if limit is None:
89 if hasattr(sys, 'tracebacklimit'):
90 limit = sys.tracebacklimit
91 list = []
92 n = 0
93 while tb is not None and (limit is None or n < limit):
94 f = tb.tb_frame
95 lineno = tb_lineno(tb)
96 co = f.f_code
97 filename = co.co_filename
98 name = co.co_name
99 line = linecache.getline(filename, lineno)
Eric S. Raymondec3bbde2001-02-09 09:39:08 +0000100 if line: line = line.strip()
Tim Petersb90f89a2001-01-15 03:26:36 +0000101 else: line = None
102 list.append((filename, lineno, name, line))
103 tb = tb.tb_next
104 n = n+1
105 return list
Guido van Rossum526beed1994-07-01 15:36:46 +0000106
Guido van Rossum28e99fe1995-08-04 04:30:30 +0000107
Guido van Rossum194e20a1995-09-20 20:31:51 +0000108def print_exception(etype, value, tb, limit=None, file=None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000109 """Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
110
111 This differs from print_tb() in the following ways: (1) if
112 traceback is not None, it prints a header "Traceback (most recent
113 call last):"; (2) it prints the exception type and value after the
114 stack trace; (3) if type is SyntaxError and value has the
115 appropriate format, it prints the line where the syntax error
Tim Petersb90f89a2001-01-15 03:26:36 +0000116 occurred with a caret on the next line indicating the approximate
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000117 position of the error.
118 """
Tim Petersb90f89a2001-01-15 03:26:36 +0000119 if not file:
120 file = sys.stderr
121 if tb:
122 _print(file, 'Traceback (most recent call last):')
123 print_tb(tb, limit, file)
124 lines = format_exception_only(etype, value)
125 for line in lines[:-1]:
126 _print(file, line, ' ')
127 _print(file, lines[-1], '')
Guido van Rossum28e99fe1995-08-04 04:30:30 +0000128
129def format_exception(etype, value, tb, limit = None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000130 """Format a stack trace and the exception information.
131
132 The arguments have the same meaning as the corresponding arguments
133 to print_exception(). The return value is a list of strings, each
Tim Petersb90f89a2001-01-15 03:26:36 +0000134 ending in a newline and some containing internal newlines. When
135 these lines are concatenated and printed, exactly the same text is
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000136 printed as does print_exception().
137 """
Tim Petersb90f89a2001-01-15 03:26:36 +0000138 if tb:
139 list = ['Traceback (most recent call last):\n']
140 list = list + format_tb(tb, limit)
141 else:
142 list = []
143 list = list + format_exception_only(etype, value)
144 return list
Guido van Rossum28e99fe1995-08-04 04:30:30 +0000145
146def format_exception_only(etype, value):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000147 """Format the exception part of a traceback.
148
149 The arguments are the exception type and value such as given by
150 sys.last_type and sys.last_value. The return value is a list of
151 strings, each ending in a newline. Normally, the list contains a
152 single string; however, for SyntaxError exceptions, it contains
153 several lines that (when printed) display detailed information
154 about where the syntax error occurred. The message indicating
155 which exception occurred is the always last string in the list.
156 """
Tim Petersb90f89a2001-01-15 03:26:36 +0000157 list = []
158 if type(etype) == types.ClassType:
159 stype = etype.__name__
160 else:
161 stype = etype
162 if value is None:
163 list.append(str(stype) + '\n')
164 else:
165 if etype is SyntaxError:
166 try:
167 msg, (filename, lineno, offset, line) = value
168 except:
169 pass
170 else:
171 if not filename: filename = "<string>"
172 list.append(' File "%s", line %d\n' %
173 (filename, lineno))
Tim Peters0bb580d2001-06-10 18:58:26 +0000174 if line is not None:
175 i = 0
176 while i < len(line) and line[i].isspace():
177 i = i+1
178 list.append(' %s\n' % line.strip())
179 if offset is not None:
180 s = ' '
181 for c in line[i:offset-1]:
182 if c.isspace():
183 s = s + c
184 else:
185 s = s + ' '
186 list.append('%s^\n' % s)
187 value = msg
Tim Petersb90f89a2001-01-15 03:26:36 +0000188 s = _some_str(value)
189 if s:
190 list.append('%s: %s\n' % (str(stype), s))
191 else:
192 list.append('%s\n' % str(stype))
193 return list
Guido van Rossum28e99fe1995-08-04 04:30:30 +0000194
Guido van Rossum2823f032000-08-22 02:04:46 +0000195def _some_str(value):
Tim Petersb90f89a2001-01-15 03:26:36 +0000196 try:
197 return str(value)
198 except:
199 return '<unprintable %s object>' % type(value).__name__
Guido van Rossum2823f032000-08-22 02:04:46 +0000200
Guido van Rossum526beed1994-07-01 15:36:46 +0000201
Guido van Rossum194e20a1995-09-20 20:31:51 +0000202def print_exc(limit=None, file=None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000203 """Shorthand for 'print_exception(sys.exc_type, sys.exc_value, sys.exc_traceback, limit, file)'.
Tim Petersb90f89a2001-01-15 03:26:36 +0000204 (In fact, it uses sys.exc_info() to retrieve the same information
205 in a thread-safe way.)"""
206 if not file:
207 file = sys.stderr
208 try:
209 etype, value, tb = sys.exc_info()
210 print_exception(etype, value, tb, limit, file)
211 finally:
212 etype = value = tb = None
Guido van Rossum526beed1994-07-01 15:36:46 +0000213
Guido van Rossum194e20a1995-09-20 20:31:51 +0000214def print_last(limit=None, file=None):
Tim Petersb90f89a2001-01-15 03:26:36 +0000215 """This is a shorthand for 'print_exception(sys.last_type,
216 sys.last_value, sys.last_traceback, limit, file)'."""
217 if not file:
218 file = sys.stderr
219 print_exception(sys.last_type, sys.last_value, sys.last_traceback,
220 limit, file)
Guido van Rossumdcc057a1996-08-12 23:18:13 +0000221
222
223def print_stack(f=None, limit=None, file=None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000224 """Print a stack trace from its invocation point.
Tim Petersa19a1682001-03-29 04:36:09 +0000225
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000226 The optional 'f' argument can be used to specify an alternate
227 stack frame at which to start. The optional 'limit' and 'file'
228 arguments have the same meaning as for print_exception().
229 """
Tim Petersb90f89a2001-01-15 03:26:36 +0000230 if f is None:
231 try:
232 raise ZeroDivisionError
233 except ZeroDivisionError:
234 f = sys.exc_info()[2].tb_frame.f_back
235 print_list(extract_stack(f, limit), file)
Guido van Rossumdcc057a1996-08-12 23:18:13 +0000236
237def format_stack(f=None, limit=None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000238 """Shorthand for 'format_list(extract_stack(f, limit))'."""
Tim Petersb90f89a2001-01-15 03:26:36 +0000239 if f is None:
240 try:
241 raise ZeroDivisionError
242 except ZeroDivisionError:
243 f = sys.exc_info()[2].tb_frame.f_back
244 return format_list(extract_stack(f, limit))
Guido van Rossumdcc057a1996-08-12 23:18:13 +0000245
246def extract_stack(f=None, limit = None):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000247 """Extract the raw traceback from the current stack frame.
248
249 The return value has the same format as for extract_tb(). The
250 optional 'f' and 'limit' arguments have the same meaning as for
251 print_stack(). Each item in the list is a quadruple (filename,
252 line number, function name, text), and the entries are in order
253 from oldest to newest stack frame.
254 """
Tim Petersb90f89a2001-01-15 03:26:36 +0000255 if f is None:
256 try:
257 raise ZeroDivisionError
258 except ZeroDivisionError:
259 f = sys.exc_info()[2].tb_frame.f_back
260 if limit is None:
261 if hasattr(sys, 'tracebacklimit'):
262 limit = sys.tracebacklimit
263 list = []
264 n = 0
265 while f is not None and (limit is None or n < limit):
266 lineno = f.f_lineno # XXX Too bad if -O is used
267 co = f.f_code
268 filename = co.co_filename
269 name = co.co_name
270 line = linecache.getline(filename, lineno)
Eric S. Raymondec3bbde2001-02-09 09:39:08 +0000271 if line: line = line.strip()
Tim Petersb90f89a2001-01-15 03:26:36 +0000272 else: line = None
273 list.append((filename, lineno, name, line))
274 f = f.f_back
275 n = n+1
276 list.reverse()
277 return list
Guido van Rossum47529661997-09-26 22:43:02 +0000278
Guido van Rossum47529661997-09-26 22:43:02 +0000279def tb_lineno(tb):
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000280 """Calculate correct line number of traceback given in tb.
Guido van Rossume7b146f2000-02-04 15:28:42 +0000281
Jeremy Hylton69e9e8b2001-03-21 19:09:31 +0000282 Even works with -O on.
283 """
Tim Petersb90f89a2001-01-15 03:26:36 +0000284 # Coded by Marc-Andre Lemburg from the example of PyCode_Addr2Line()
285 # in compile.c.
286 # Revised version by Jim Hugunin to work with JPython too.
Guido van Rossume7b146f2000-02-04 15:28:42 +0000287
Tim Petersb90f89a2001-01-15 03:26:36 +0000288 c = tb.tb_frame.f_code
289 if not hasattr(c, 'co_lnotab'):
290 return tb.tb_lineno
Guido van Rossum6e73af71998-02-26 17:25:02 +0000291
Tim Petersb90f89a2001-01-15 03:26:36 +0000292 tab = c.co_lnotab
293 line = c.co_firstlineno
294 stopat = tb.tb_lasti
295 addr = 0
296 for i in range(0, len(tab), 2):
297 addr = addr + ord(tab[i])
298 if addr > stopat:
299 break
300 line = line + ord(tab[i+1])
301 return line