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1 1 # -*- coding: utf-8 -*-
2 2 """
3 3 Verbose and colourful traceback formatting.
4 4
5 5 **ColorTB**
6 6
7 7 I've always found it a bit hard to visually parse tracebacks in Python. The
8 8 ColorTB class is a solution to that problem. It colors the different parts of a
9 9 traceback in a manner similar to what you would expect from a syntax-highlighting
10 10 text editor.
11 11
12 12 Installation instructions for ColorTB::
13 13
14 14 import sys,ultratb
15 15 sys.excepthook = ultratb.ColorTB()
16 16
17 17 **VerboseTB**
18 18
19 19 I've also included a port of Ka-Ping Yee's "cgitb.py" that produces all kinds
20 20 of useful info when a traceback occurs. Ping originally had it spit out HTML
21 21 and intended it for CGI programmers, but why should they have all the fun? I
22 22 altered it to spit out colored text to the terminal. It's a bit overwhelming,
23 23 but kind of neat, and maybe useful for long-running programs that you believe
24 24 are bug-free. If a crash *does* occur in that type of program you want details.
25 25 Give it a shot--you'll love it or you'll hate it.
26 26
27 27 .. note::
28 28
29 29 The Verbose mode prints the variables currently visible where the exception
30 30 happened (shortening their strings if too long). This can potentially be
31 31 very slow, if you happen to have a huge data structure whose string
32 32 representation is complex to compute. Your computer may appear to freeze for
33 33 a while with cpu usage at 100%. If this occurs, you can cancel the traceback
34 34 with Ctrl-C (maybe hitting it more than once).
35 35
36 36 If you encounter this kind of situation often, you may want to use the
37 37 Verbose_novars mode instead of the regular Verbose, which avoids formatting
38 38 variables (but otherwise includes the information and context given by
39 39 Verbose).
40 40
41 41 .. note::
42 42
43 43 The verbose mode print all variables in the stack, which means it can
44 44 potentially leak sensitive information like access keys, or unencrypted
45 45 password.
46 46
47 47 Installation instructions for VerboseTB::
48 48
49 49 import sys,ultratb
50 50 sys.excepthook = ultratb.VerboseTB()
51 51
52 52 Note: Much of the code in this module was lifted verbatim from the standard
53 53 library module 'traceback.py' and Ka-Ping Yee's 'cgitb.py'.
54 54
55 55 Color schemes
56 56 -------------
57 57
58 58 The colors are defined in the class TBTools through the use of the
59 59 ColorSchemeTable class. Currently the following exist:
60 60
61 61 - NoColor: allows all of this module to be used in any terminal (the color
62 62 escapes are just dummy blank strings).
63 63
64 64 - Linux: is meant to look good in a terminal like the Linux console (black
65 65 or very dark background).
66 66
67 67 - LightBG: similar to Linux but swaps dark/light colors to be more readable
68 68 in light background terminals.
69 69
70 70 - Neutral: a neutral color scheme that should be readable on both light and
71 71 dark background
72 72
73 73 You can implement other color schemes easily, the syntax is fairly
74 74 self-explanatory. Please send back new schemes you develop to the author for
75 75 possible inclusion in future releases.
76 76
77 77 Inheritance diagram:
78 78
79 79 .. inheritance-diagram:: IPython.core.ultratb
80 80 :parts: 3
81 81 """
82 82
83 83 #*****************************************************************************
84 84 # Copyright (C) 2001 Nathaniel Gray <n8gray@caltech.edu>
85 85 # Copyright (C) 2001-2004 Fernando Perez <fperez@colorado.edu>
86 86 #
87 87 # Distributed under the terms of the BSD License. The full license is in
88 88 # the file COPYING, distributed as part of this software.
89 89 #*****************************************************************************
90 90
91 91
92 92 import inspect
93 93 import linecache
94 94 import pydoc
95 95 import sys
96 96 import time
97 97 import traceback
98 98
99 99 import stack_data
100 100 from pygments.formatters.terminal256 import Terminal256Formatter
101 101 from pygments.styles import get_style_by_name
102 102
103 103 # IPython's own modules
104 104 from IPython import get_ipython
105 105 from IPython.core import debugger
106 106 from IPython.core.display_trap import DisplayTrap
107 107 from IPython.core.excolors import exception_colors
108 108 from IPython.utils import path as util_path
109 109 from IPython.utils import py3compat
110 110 from IPython.utils.terminal import get_terminal_size
111 111
112 112 import IPython.utils.colorable as colorable
113 113
114 114 # Globals
115 115 # amount of space to put line numbers before verbose tracebacks
116 116 INDENT_SIZE = 8
117 117
118 118 # Default color scheme. This is used, for example, by the traceback
119 119 # formatter. When running in an actual IPython instance, the user's rc.colors
120 120 # value is used, but having a module global makes this functionality available
121 121 # to users of ultratb who are NOT running inside ipython.
122 122 DEFAULT_SCHEME = 'NoColor'
123 123
124 124 # ---------------------------------------------------------------------------
125 125 # Code begins
126 126
127 127 # Helper function -- largely belongs to VerboseTB, but we need the same
128 128 # functionality to produce a pseudo verbose TB for SyntaxErrors, so that they
129 129 # can be recognized properly by ipython.el's py-traceback-line-re
130 130 # (SyntaxErrors have to be treated specially because they have no traceback)
131 131
132 132
133 133 def _format_traceback_lines(lines, Colors, has_colors, lvals):
134 134 """
135 135 Format tracebacks lines with pointing arrow, leading numbers...
136 136
137 137 Parameters
138 138 ==========
139 139
140 140 lines: list[Line]
141 141 Colors:
142 142 ColorScheme used.
143 143 lvals: str
144 144 Values of local variables, already colored, to inject just after the error line.
145 145 """
146 146 numbers_width = INDENT_SIZE - 1
147 147 res = []
148 148
149 149 for stack_line in lines:
150 150 if stack_line is stack_data.LINE_GAP:
151 151 res.append('%s (...)%s\n' % (Colors.linenoEm, Colors.Normal))
152 152 continue
153 153
154 154 line = stack_line.render(pygmented=has_colors).rstrip('\n') + '\n'
155 155 lineno = stack_line.lineno
156 156 if stack_line.is_current:
157 157 # This is the line with the error
158 158 pad = numbers_width - len(str(lineno))
159 159 num = '%s%s' % (debugger.make_arrow(pad), str(lineno))
160 160 start_color = Colors.linenoEm
161 161 else:
162 162 num = '%*s' % (numbers_width, lineno)
163 163 start_color = Colors.lineno
164 164
165 165 line = '%s%s%s %s' % (start_color, num, Colors.Normal, line)
166 166
167 167 res.append(line)
168 168 if lvals and stack_line.is_current:
169 169 res.append(lvals + '\n')
170 170 return res
171 171
172 172
173 173 #---------------------------------------------------------------------------
174 174 # Module classes
175 175 class TBTools(colorable.Colorable):
176 176 """Basic tools used by all traceback printer classes."""
177 177
178 178 # Number of frames to skip when reporting tracebacks
179 179 tb_offset = 0
180 180
181 181 def __init__(self, color_scheme='NoColor', call_pdb=False, ostream=None, parent=None, config=None):
182 182 # Whether to call the interactive pdb debugger after printing
183 183 # tracebacks or not
184 184 super(TBTools, self).__init__(parent=parent, config=config)
185 185 self.call_pdb = call_pdb
186 186
187 187 # Output stream to write to. Note that we store the original value in
188 188 # a private attribute and then make the public ostream a property, so
189 189 # that we can delay accessing sys.stdout until runtime. The way
190 190 # things are written now, the sys.stdout object is dynamically managed
191 191 # so a reference to it should NEVER be stored statically. This
192 192 # property approach confines this detail to a single location, and all
193 193 # subclasses can simply access self.ostream for writing.
194 194 self._ostream = ostream
195 195
196 196 # Create color table
197 197 self.color_scheme_table = exception_colors()
198 198
199 199 self.set_colors(color_scheme)
200 200 self.old_scheme = color_scheme # save initial value for toggles
201 201
202 202 if call_pdb:
203 203 self.pdb = debugger.Pdb()
204 204 else:
205 205 self.pdb = None
206 206
207 207 def _get_ostream(self):
208 208 """Output stream that exceptions are written to.
209 209
210 210 Valid values are:
211 211
212 212 - None: the default, which means that IPython will dynamically resolve
213 213 to sys.stdout. This ensures compatibility with most tools, including
214 214 Windows (where plain stdout doesn't recognize ANSI escapes).
215 215
216 216 - Any object with 'write' and 'flush' attributes.
217 217 """
218 218 return sys.stdout if self._ostream is None else self._ostream
219 219
220 220 def _set_ostream(self, val):
221 221 assert val is None or (hasattr(val, 'write') and hasattr(val, 'flush'))
222 222 self._ostream = val
223 223
224 224 ostream = property(_get_ostream, _set_ostream)
225 225
226 226 def get_parts_of_chained_exception(self, evalue):
227 227 def get_chained_exception(exception_value):
228 228 cause = getattr(exception_value, '__cause__', None)
229 229 if cause:
230 230 return cause
231 231 if getattr(exception_value, '__suppress_context__', False):
232 232 return None
233 233 return getattr(exception_value, '__context__', None)
234 234
235 235 chained_evalue = get_chained_exception(evalue)
236 236
237 237 if chained_evalue:
238 238 return chained_evalue.__class__, chained_evalue, chained_evalue.__traceback__
239 239
240 240 def prepare_chained_exception_message(self, cause):
241 241 direct_cause = "\nThe above exception was the direct cause of the following exception:\n"
242 242 exception_during_handling = "\nDuring handling of the above exception, another exception occurred:\n"
243 243
244 244 if cause:
245 245 message = [[direct_cause]]
246 246 else:
247 247 message = [[exception_during_handling]]
248 248 return message
249 249
250 250 @property
251 251 def has_colors(self):
252 252 return self.color_scheme_table.active_scheme_name.lower() != "nocolor"
253 253
254 254 def set_colors(self, *args, **kw):
255 255 """Shorthand access to the color table scheme selector method."""
256 256
257 257 # Set own color table
258 258 self.color_scheme_table.set_active_scheme(*args, **kw)
259 259 # for convenience, set Colors to the active scheme
260 260 self.Colors = self.color_scheme_table.active_colors
261 261 # Also set colors of debugger
262 262 if hasattr(self, 'pdb') and self.pdb is not None:
263 263 self.pdb.set_colors(*args, **kw)
264 264
265 265 def color_toggle(self):
266 266 """Toggle between the currently active color scheme and NoColor."""
267 267
268 268 if self.color_scheme_table.active_scheme_name == 'NoColor':
269 269 self.color_scheme_table.set_active_scheme(self.old_scheme)
270 270 self.Colors = self.color_scheme_table.active_colors
271 271 else:
272 272 self.old_scheme = self.color_scheme_table.active_scheme_name
273 273 self.color_scheme_table.set_active_scheme('NoColor')
274 274 self.Colors = self.color_scheme_table.active_colors
275 275
276 276 def stb2text(self, stb):
277 277 """Convert a structured traceback (a list) to a string."""
278 278 return '\n'.join(stb)
279 279
280 280 def text(self, etype, value, tb, tb_offset=None, context=5):
281 281 """Return formatted traceback.
282 282
283 283 Subclasses may override this if they add extra arguments.
284 284 """
285 285 tb_list = self.structured_traceback(etype, value, tb,
286 286 tb_offset, context)
287 287 return self.stb2text(tb_list)
288 288
289 289 def structured_traceback(self, etype, evalue, tb, tb_offset=None,
290 290 context=5, mode=None):
291 291 """Return a list of traceback frames.
292 292
293 293 Must be implemented by each class.
294 294 """
295 295 raise NotImplementedError()
296 296
297 297
298 298 #---------------------------------------------------------------------------
299 299 class ListTB(TBTools):
300 300 """Print traceback information from a traceback list, with optional color.
301 301
302 302 Calling requires 3 arguments: (etype, evalue, elist)
303 303 as would be obtained by::
304 304
305 305 etype, evalue, tb = sys.exc_info()
306 306 if tb:
307 307 elist = traceback.extract_tb(tb)
308 308 else:
309 309 elist = None
310 310
311 311 It can thus be used by programs which need to process the traceback before
312 312 printing (such as console replacements based on the code module from the
313 313 standard library).
314 314
315 315 Because they are meant to be called without a full traceback (only a
316 316 list), instances of this class can't call the interactive pdb debugger."""
317 317
318 318 def __init__(self, color_scheme='NoColor', call_pdb=False, ostream=None, parent=None, config=None):
319 319 TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
320 320 ostream=ostream, parent=parent,config=config)
321 321
322 322 def __call__(self, etype, value, elist):
323 323 self.ostream.flush()
324 324 self.ostream.write(self.text(etype, value, elist))
325 325 self.ostream.write('\n')
326 326
327 327 def _extract_tb(self, tb):
328 328 if tb:
329 329 return traceback.extract_tb(tb)
330 330 else:
331 331 return None
332 332
333 333 def structured_traceback(self, etype, evalue, etb=None, tb_offset=None,
334 334 context=5):
335 335 """Return a color formatted string with the traceback info.
336 336
337 337 Parameters
338 338 ----------
339 339 etype : exception type
340 340 Type of the exception raised.
341 341
342 342 evalue : object
343 343 Data stored in the exception
344 344
345 345 etb : object
346 346 If list: List of frames, see class docstring for details.
347 347 If Traceback: Traceback of the exception.
348 348
349 349 tb_offset : int, optional
350 350 Number of frames in the traceback to skip. If not given, the
351 351 instance evalue is used (set in constructor).
352 352
353 353 context : int, optional
354 354 Number of lines of context information to print.
355 355
356 356 Returns
357 357 -------
358 358 String with formatted exception.
359 359 """
360 360 # This is a workaround to get chained_exc_ids in recursive calls
361 361 # etb should not be a tuple if structured_traceback is not recursive
362 362 if isinstance(etb, tuple):
363 363 etb, chained_exc_ids = etb
364 364 else:
365 365 chained_exc_ids = set()
366 366
367 367 if isinstance(etb, list):
368 368 elist = etb
369 369 elif etb is not None:
370 370 elist = self._extract_tb(etb)
371 371 else:
372 372 elist = []
373 373 tb_offset = self.tb_offset if tb_offset is None else tb_offset
374 374 Colors = self.Colors
375 375 out_list = []
376 376 if elist:
377 377
378 378 if tb_offset and len(elist) > tb_offset:
379 379 elist = elist[tb_offset:]
380 380
381 381 out_list.append('Traceback %s(most recent call last)%s:' %
382 382 (Colors.normalEm, Colors.Normal) + '\n')
383 383 out_list.extend(self._format_list(elist))
384 384 # The exception info should be a single entry in the list.
385 385 lines = ''.join(self._format_exception_only(etype, evalue))
386 386 out_list.append(lines)
387 387
388 388 exception = self.get_parts_of_chained_exception(evalue)
389 389
390 390 if exception and not id(exception[1]) in chained_exc_ids:
391 391 chained_exception_message = self.prepare_chained_exception_message(
392 392 evalue.__cause__)[0]
393 393 etype, evalue, etb = exception
394 394 # Trace exception to avoid infinite 'cause' loop
395 395 chained_exc_ids.add(id(exception[1]))
396 396 chained_exceptions_tb_offset = 0
397 397 out_list = (
398 398 self.structured_traceback(
399 399 etype, evalue, (etb, chained_exc_ids),
400 400 chained_exceptions_tb_offset, context)
401 401 + chained_exception_message
402 402 + out_list)
403 403
404 404 return out_list
405 405
406 406 def _format_list(self, extracted_list):
407 407 """Format a list of traceback entry tuples for printing.
408 408
409 409 Given a list of tuples as returned by extract_tb() or
410 410 extract_stack(), return a list of strings ready for printing.
411 411 Each string in the resulting list corresponds to the item with the
412 412 same index in the argument list. Each string ends in a newline;
413 413 the strings may contain internal newlines as well, for those items
414 414 whose source text line is not None.
415 415
416 416 Lifted almost verbatim from traceback.py
417 417 """
418 418
419 419 Colors = self.Colors
420 420 list = []
421 421 for filename, lineno, name, line in extracted_list[:-1]:
422 422 item = ' File %s"%s"%s, line %s%d%s, in %s%s%s\n' % \
423 423 (Colors.filename, filename, Colors.Normal,
424 424 Colors.lineno, lineno, Colors.Normal,
425 425 Colors.name, name, Colors.Normal)
426 426 if line:
427 427 item += ' %s\n' % line.strip()
428 428 list.append(item)
429 429 # Emphasize the last entry
430 430 filename, lineno, name, line = extracted_list[-1]
431 431 item = '%s File %s"%s"%s, line %s%d%s, in %s%s%s%s\n' % \
432 432 (Colors.normalEm,
433 433 Colors.filenameEm, filename, Colors.normalEm,
434 434 Colors.linenoEm, lineno, Colors.normalEm,
435 435 Colors.nameEm, name, Colors.normalEm,
436 436 Colors.Normal)
437 437 if line:
438 438 item += '%s %s%s\n' % (Colors.line, line.strip(),
439 439 Colors.Normal)
440 440 list.append(item)
441 441 return list
442 442
443 443 def _format_exception_only(self, etype, value):
444 444 """Format the exception part of a traceback.
445 445
446 446 The arguments are the exception type and value such as given by
447 447 sys.exc_info()[:2]. The return value is a list of strings, each ending
448 448 in a newline. Normally, the list contains a single string; however,
449 449 for SyntaxError exceptions, it contains several lines that (when
450 450 printed) display detailed information about where the syntax error
451 451 occurred. The message indicating which exception occurred is the
452 452 always last string in the list.
453 453
454 454 Also lifted nearly verbatim from traceback.py
455 455 """
456 456 have_filedata = False
457 457 Colors = self.Colors
458 458 list = []
459 459 stype = py3compat.cast_unicode(Colors.excName + etype.__name__ + Colors.Normal)
460 460 if value is None:
461 461 # Not sure if this can still happen in Python 2.6 and above
462 462 list.append(stype + '\n')
463 463 else:
464 464 if issubclass(etype, SyntaxError):
465 465 have_filedata = True
466 466 if not value.filename: value.filename = "<string>"
467 467 if value.lineno:
468 468 lineno = value.lineno
469 469 textline = linecache.getline(value.filename, value.lineno)
470 470 else:
471 471 lineno = 'unknown'
472 472 textline = ''
473 473 list.append('%s File %s"%s"%s, line %s%s%s\n' % \
474 474 (Colors.normalEm,
475 475 Colors.filenameEm, py3compat.cast_unicode(value.filename), Colors.normalEm,
476 476 Colors.linenoEm, lineno, Colors.Normal ))
477 477 if textline == '':
478 478 textline = py3compat.cast_unicode(value.text, "utf-8")
479 479
480 480 if textline is not None:
481 481 i = 0
482 482 while i < len(textline) and textline[i].isspace():
483 483 i += 1
484 484 list.append('%s %s%s\n' % (Colors.line,
485 485 textline.strip(),
486 486 Colors.Normal))
487 487 if value.offset is not None:
488 488 s = ' '
489 489 for c in textline[i:value.offset - 1]:
490 490 if c.isspace():
491 491 s += c
492 492 else:
493 493 s += ' '
494 494 list.append('%s%s^%s\n' % (Colors.caret, s,
495 495 Colors.Normal))
496 496
497 497 try:
498 498 s = value.msg
499 499 except Exception:
500 500 s = self._some_str(value)
501 501 if s:
502 502 list.append('%s%s:%s %s\n' % (stype, Colors.excName,
503 503 Colors.Normal, s))
504 504 else:
505 505 list.append('%s\n' % stype)
506 506
507 507 # sync with user hooks
508 508 if have_filedata:
509 509 ipinst = get_ipython()
510 510 if ipinst is not None:
511 511 ipinst.hooks.synchronize_with_editor(value.filename, value.lineno, 0)
512 512
513 513 return list
514 514
515 515 def get_exception_only(self, etype, value):
516 516 """Only print the exception type and message, without a traceback.
517 517
518 518 Parameters
519 519 ----------
520 520 etype : exception type
521 521 value : exception value
522 522 """
523 523 return ListTB.structured_traceback(self, etype, value)
524 524
525 525 def show_exception_only(self, etype, evalue):
526 526 """Only print the exception type and message, without a traceback.
527 527
528 528 Parameters
529 529 ----------
530 530 etype : exception type
531 531 value : exception value
532 532 """
533 533 # This method needs to use __call__ from *this* class, not the one from
534 534 # a subclass whose signature or behavior may be different
535 535 ostream = self.ostream
536 536 ostream.flush()
537 537 ostream.write('\n'.join(self.get_exception_only(etype, evalue)))
538 538 ostream.flush()
539 539
540 540 def _some_str(self, value):
541 541 # Lifted from traceback.py
542 542 try:
543 543 return py3compat.cast_unicode(str(value))
544 544 except:
545 545 return u'<unprintable %s object>' % type(value).__name__
546 546
547 547
548 548 #----------------------------------------------------------------------------
549 549 class VerboseTB(TBTools):
550 550 """A port of Ka-Ping Yee's cgitb.py module that outputs color text instead
551 551 of HTML. Requires inspect and pydoc. Crazy, man.
552 552
553 553 Modified version which optionally strips the topmost entries from the
554 554 traceback, to be used with alternate interpreters (because their own code
555 555 would appear in the traceback)."""
556 556
557 557 def __init__(self, color_scheme='Linux', call_pdb=False, ostream=None,
558 558 tb_offset=0, long_header=False, include_vars=True,
559 559 check_cache=None, debugger_cls = None,
560 560 parent=None, config=None):
561 561 """Specify traceback offset, headers and color scheme.
562 562
563 563 Define how many frames to drop from the tracebacks. Calling it with
564 564 tb_offset=1 allows use of this handler in interpreters which will have
565 565 their own code at the top of the traceback (VerboseTB will first
566 566 remove that frame before printing the traceback info)."""
567 567 TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
568 568 ostream=ostream, parent=parent, config=config)
569 569 self.tb_offset = tb_offset
570 570 self.long_header = long_header
571 571 self.include_vars = include_vars
572 572 # By default we use linecache.checkcache, but the user can provide a
573 573 # different check_cache implementation. This is used by the IPython
574 574 # kernel to provide tracebacks for interactive code that is cached,
575 575 # by a compiler instance that flushes the linecache but preserves its
576 576 # own code cache.
577 577 if check_cache is None:
578 578 check_cache = linecache.checkcache
579 579 self.check_cache = check_cache
580 580
581 581 self.debugger_cls = debugger_cls or debugger.Pdb
582 582 self.skip_hidden = True
583 583
584 584 def format_record(self, frame_info):
585 585 """Format a single stack frame"""
586 586 Colors = self.Colors # just a shorthand + quicker name lookup
587 587 ColorsNormal = Colors.Normal # used a lot
588 588
589 589
590 590
591 591 if isinstance(frame_info, stack_data.RepeatedFrames):
592 592 return ' %s[... skipping similar frames: %s]%s\n' % (
593 593 Colors.excName, frame_info.description, ColorsNormal)
594 594
595 595 indent = ' ' * INDENT_SIZE
596 596 em_normal = '%s\n%s%s' % (Colors.valEm, indent, ColorsNormal)
597 597 tpl_link = '%s%%s%s' % (Colors.filenameEm, ColorsNormal)
598 598 tpl_call = 'in %s%%s%s%%s%s' % (Colors.vName, Colors.valEm,
599 599 ColorsNormal)
600 600 tpl_call_fail = 'in %s%%s%s(***failed resolving arguments***)%s' % \
601 601 (Colors.vName, Colors.valEm, ColorsNormal)
602 602 tpl_local_var = '%s%%s%s' % (Colors.vName, ColorsNormal)
603 603 tpl_name_val = '%%s %s= %%s%s' % (Colors.valEm, ColorsNormal)
604 604
605 605 file = frame_info.filename
606 606 file = py3compat.cast_unicode(file, util_path.fs_encoding)
607 607 link = tpl_link % util_path.compress_user(file)
608 608 args, varargs, varkw, locals_ = inspect.getargvalues(frame_info.frame)
609 609
610 610 func = frame_info.executing.code_qualname()
611 611 if func == '<module>':
612 612 call = tpl_call % (func, '')
613 613 else:
614 614 # Decide whether to include variable details or not
615 615 var_repr = eqrepr if self.include_vars else nullrepr
616 616 try:
617 617 call = tpl_call % (func, inspect.formatargvalues(args,
618 618 varargs, varkw,
619 619 locals_, formatvalue=var_repr))
620 620 except KeyError:
621 621 # This happens in situations like errors inside generator
622 622 # expressions, where local variables are listed in the
623 623 # line, but can't be extracted from the frame. I'm not
624 624 # 100% sure this isn't actually a bug in inspect itself,
625 625 # but since there's no info for us to compute with, the
626 626 # best we can do is report the failure and move on. Here
627 627 # we must *not* call any traceback construction again,
628 628 # because that would mess up use of %debug later on. So we
629 629 # simply report the failure and move on. The only
630 630 # limitation will be that this frame won't have locals
631 631 # listed in the call signature. Quite subtle problem...
632 632 # I can't think of a good way to validate this in a unit
633 633 # test, but running a script consisting of:
634 634 # dict( (k,v.strip()) for (k,v) in range(10) )
635 635 # will illustrate the error, if this exception catch is
636 636 # disabled.
637 637 call = tpl_call_fail % func
638 638
639 639 lvals = ''
640 640 lvals_list = []
641 641 if self.include_vars:
642 642 for var in frame_info.variables_in_executing_piece:
643 643 lvals_list.append(tpl_name_val % (var.name, repr(var.value)))
644 644 if lvals_list:
645 645 lvals = '%s%s' % (indent, em_normal.join(lvals_list))
646 646
647 647 result = '%s %s\n' % (link, call)
648 648
649 649 result += ''.join(_format_traceback_lines(frame_info.lines, Colors, self.has_colors, lvals))
650 650 return result
651 651
652 652 def prepare_header(self, etype, long_version=False):
653 653 colors = self.Colors # just a shorthand + quicker name lookup
654 654 colorsnormal = colors.Normal # used a lot
655 655 exc = '%s%s%s' % (colors.excName, etype, colorsnormal)
656 656 width = min(75, get_terminal_size()[0])
657 657 if long_version:
658 658 # Header with the exception type, python version, and date
659 659 pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
660 660 date = time.ctime(time.time())
661 661
662 662 head = '%s%s%s\n%s%s%s\n%s' % (colors.topline, '-' * width, colorsnormal,
663 663 exc, ' ' * (width - len(str(etype)) - len(pyver)),
664 664 pyver, date.rjust(width) )
665 665 head += "\nA problem occurred executing Python code. Here is the sequence of function" \
666 666 "\ncalls leading up to the error, with the most recent (innermost) call last."
667 667 else:
668 668 # Simplified header
669 669 head = '%s%s' % (exc, 'Traceback (most recent call last)'. \
670 670 rjust(width - len(str(etype))) )
671 671
672 672 return head
673 673
674 674 def format_exception(self, etype, evalue):
675 675 colors = self.Colors # just a shorthand + quicker name lookup
676 676 colorsnormal = colors.Normal # used a lot
677 677 # Get (safely) a string form of the exception info
678 678 try:
679 679 etype_str, evalue_str = map(str, (etype, evalue))
680 680 except:
681 681 # User exception is improperly defined.
682 682 etype, evalue = str, sys.exc_info()[:2]
683 683 etype_str, evalue_str = map(str, (etype, evalue))
684 684 # ... and format it
685 685 return ['%s%s%s: %s' % (colors.excName, etype_str,
686 686 colorsnormal, py3compat.cast_unicode(evalue_str))]
687 687
688 688 def format_exception_as_a_whole(self, etype, evalue, etb, number_of_lines_of_context, tb_offset):
689 689 """Formats the header, traceback and exception message for a single exception.
690 690
691 691 This may be called multiple times by Python 3 exception chaining
692 692 (PEP 3134).
693 693 """
694 694 # some locals
695 695 orig_etype = etype
696 696 try:
697 697 etype = etype.__name__
698 698 except AttributeError:
699 699 pass
700 700
701 701 tb_offset = self.tb_offset if tb_offset is None else tb_offset
702 702 head = self.prepare_header(etype, self.long_header)
703 703 records = self.get_records(etb, number_of_lines_of_context, tb_offset)
704 704
705 705 frames = []
706 706 skipped = 0
707 707 for r in records:
708 708 if not isinstance(r, stack_data.RepeatedFrames) and self.skip_hidden:
709 709 if r.frame.f_locals.get("__tracebackhide__", 0):
710 710 skipped += 1
711 711 continue
712 712 if skipped:
713 713 Colors = self.Colors # just a shorthand + quicker name lookup
714 714 ColorsNormal = Colors.Normal # used a lot
715 715 frames.append(
716 716 " %s[... skipping hidden %s frame]%s\n"
717 717 % (Colors.excName, skipped, ColorsNormal)
718 718 )
719 719 skipped = 0
720 720 frames.append(self.format_record(r))
721
721 if skipped:
722 Colors = self.Colors # just a shorthand + quicker name lookup
723 ColorsNormal = Colors.Normal # used a lot
724 frames.append(
725 " %s[... skipping hidden %s frame]%s\n"
726 % (Colors.excName, skipped, ColorsNormal)
727 )
722 728
723 729 formatted_exception = self.format_exception(etype, evalue)
724 730 if records:
725 731 frame_info = records[-1]
726 732 ipinst = get_ipython()
727 733 if ipinst is not None:
728 734 ipinst.hooks.synchronize_with_editor(frame_info.filename, frame_info.lineno, 0)
729 735
730 736 return [[head] + frames + [''.join(formatted_exception[0])]]
731 737
732 738 def get_records(self, etb, number_of_lines_of_context, tb_offset):
733 739 context = number_of_lines_of_context - 1
734 740 after = context // 2
735 741 before = context - after
736 742 if self.has_colors:
737 743 style = get_style_by_name('default')
738 744 style = stack_data.style_with_executing_node(style, 'bg:#00005f')
739 745 formatter = Terminal256Formatter(style=style)
740 746 else:
741 747 formatter = None
742 748 options = stack_data.Options(
743 749 before=before,
744 750 after=after,
745 751 pygments_formatter=formatter,
746 752 )
747 753 return list(stack_data.FrameInfo.stack_data(etb, options=options))[tb_offset:]
748 754
749 755 def structured_traceback(self, etype, evalue, etb, tb_offset=None,
750 756 number_of_lines_of_context=5):
751 757 """Return a nice text document describing the traceback."""
752 758
753 759 formatted_exception = self.format_exception_as_a_whole(etype, evalue, etb, number_of_lines_of_context,
754 760 tb_offset)
755 761
756 762 colors = self.Colors # just a shorthand + quicker name lookup
757 763 colorsnormal = colors.Normal # used a lot
758 764 head = '%s%s%s' % (colors.topline, '-' * min(75, get_terminal_size()[0]), colorsnormal)
759 765 structured_traceback_parts = [head]
760 766 chained_exceptions_tb_offset = 0
761 767 lines_of_context = 3
762 768 formatted_exceptions = formatted_exception
763 769 exception = self.get_parts_of_chained_exception(evalue)
764 770 if exception:
765 771 formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
766 772 etype, evalue, etb = exception
767 773 else:
768 774 evalue = None
769 775 chained_exc_ids = set()
770 776 while evalue:
771 777 formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,
772 778 chained_exceptions_tb_offset)
773 779 exception = self.get_parts_of_chained_exception(evalue)
774 780
775 781 if exception and not id(exception[1]) in chained_exc_ids:
776 782 chained_exc_ids.add(id(exception[1])) # trace exception to avoid infinite 'cause' loop
777 783 formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
778 784 etype, evalue, etb = exception
779 785 else:
780 786 evalue = None
781 787
782 788 # we want to see exceptions in a reversed order:
783 789 # the first exception should be on top
784 790 for formatted_exception in reversed(formatted_exceptions):
785 791 structured_traceback_parts += formatted_exception
786 792
787 793 return structured_traceback_parts
788 794
789 795 def debugger(self, force=False):
790 796 """Call up the pdb debugger if desired, always clean up the tb
791 797 reference.
792 798
793 799 Keywords:
794 800
795 801 - force(False): by default, this routine checks the instance call_pdb
796 802 flag and does not actually invoke the debugger if the flag is false.
797 803 The 'force' option forces the debugger to activate even if the flag
798 804 is false.
799 805
800 806 If the call_pdb flag is set, the pdb interactive debugger is
801 807 invoked. In all cases, the self.tb reference to the current traceback
802 808 is deleted to prevent lingering references which hamper memory
803 809 management.
804 810
805 811 Note that each call to pdb() does an 'import readline', so if your app
806 812 requires a special setup for the readline completers, you'll have to
807 813 fix that by hand after invoking the exception handler."""
808 814
809 815 if force or self.call_pdb:
810 816 if self.pdb is None:
811 817 self.pdb = self.debugger_cls()
812 818 # the system displayhook may have changed, restore the original
813 819 # for pdb
814 820 display_trap = DisplayTrap(hook=sys.__displayhook__)
815 821 with display_trap:
816 822 self.pdb.reset()
817 823 # Find the right frame so we don't pop up inside ipython itself
818 824 if hasattr(self, 'tb') and self.tb is not None:
819 825 etb = self.tb
820 826 else:
821 827 etb = self.tb = sys.last_traceback
822 828 while self.tb is not None and self.tb.tb_next is not None:
823 829 self.tb = self.tb.tb_next
824 830 if etb and etb.tb_next:
825 831 etb = etb.tb_next
826 832 self.pdb.botframe = etb.tb_frame
827 833 self.pdb.interaction(None, etb)
828 834
829 835 if hasattr(self, 'tb'):
830 836 del self.tb
831 837
832 838 def handler(self, info=None):
833 839 (etype, evalue, etb) = info or sys.exc_info()
834 840 self.tb = etb
835 841 ostream = self.ostream
836 842 ostream.flush()
837 843 ostream.write(self.text(etype, evalue, etb))
838 844 ostream.write('\n')
839 845 ostream.flush()
840 846
841 847 # Changed so an instance can just be called as VerboseTB_inst() and print
842 848 # out the right info on its own.
843 849 def __call__(self, etype=None, evalue=None, etb=None):
844 850 """This hook can replace sys.excepthook (for Python 2.1 or higher)."""
845 851 if etb is None:
846 852 self.handler()
847 853 else:
848 854 self.handler((etype, evalue, etb))
849 855 try:
850 856 self.debugger()
851 857 except KeyboardInterrupt:
852 858 print("\nKeyboardInterrupt")
853 859
854 860
855 861 #----------------------------------------------------------------------------
856 862 class FormattedTB(VerboseTB, ListTB):
857 863 """Subclass ListTB but allow calling with a traceback.
858 864
859 865 It can thus be used as a sys.excepthook for Python > 2.1.
860 866
861 867 Also adds 'Context' and 'Verbose' modes, not available in ListTB.
862 868
863 869 Allows a tb_offset to be specified. This is useful for situations where
864 870 one needs to remove a number of topmost frames from the traceback (such as
865 871 occurs with python programs that themselves execute other python code,
866 872 like Python shells). """
867 873
868 874 def __init__(self, mode='Plain', color_scheme='Linux', call_pdb=False,
869 875 ostream=None,
870 876 tb_offset=0, long_header=False, include_vars=False,
871 877 check_cache=None, debugger_cls=None,
872 878 parent=None, config=None):
873 879
874 880 # NEVER change the order of this list. Put new modes at the end:
875 881 self.valid_modes = ['Plain', 'Context', 'Verbose', 'Minimal']
876 882 self.verbose_modes = self.valid_modes[1:3]
877 883
878 884 VerboseTB.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
879 885 ostream=ostream, tb_offset=tb_offset,
880 886 long_header=long_header, include_vars=include_vars,
881 887 check_cache=check_cache, debugger_cls=debugger_cls,
882 888 parent=parent, config=config)
883 889
884 890 # Different types of tracebacks are joined with different separators to
885 891 # form a single string. They are taken from this dict
886 892 self._join_chars = dict(Plain='', Context='\n', Verbose='\n',
887 893 Minimal='')
888 894 # set_mode also sets the tb_join_char attribute
889 895 self.set_mode(mode)
890 896
891 897 def structured_traceback(self, etype, value, tb, tb_offset=None, number_of_lines_of_context=5):
892 898 tb_offset = self.tb_offset if tb_offset is None else tb_offset
893 899 mode = self.mode
894 900 if mode in self.verbose_modes:
895 901 # Verbose modes need a full traceback
896 902 return VerboseTB.structured_traceback(
897 903 self, etype, value, tb, tb_offset, number_of_lines_of_context
898 904 )
899 905 elif mode == 'Minimal':
900 906 return ListTB.get_exception_only(self, etype, value)
901 907 else:
902 908 # We must check the source cache because otherwise we can print
903 909 # out-of-date source code.
904 910 self.check_cache()
905 911 # Now we can extract and format the exception
906 912 return ListTB.structured_traceback(
907 913 self, etype, value, tb, tb_offset, number_of_lines_of_context
908 914 )
909 915
910 916 def stb2text(self, stb):
911 917 """Convert a structured traceback (a list) to a string."""
912 918 return self.tb_join_char.join(stb)
913 919
914 920
915 921 def set_mode(self, mode=None):
916 922 """Switch to the desired mode.
917 923
918 924 If mode is not specified, cycles through the available modes."""
919 925
920 926 if not mode:
921 927 new_idx = (self.valid_modes.index(self.mode) + 1 ) % \
922 928 len(self.valid_modes)
923 929 self.mode = self.valid_modes[new_idx]
924 930 elif mode not in self.valid_modes:
925 931 raise ValueError('Unrecognized mode in FormattedTB: <' + mode + '>\n'
926 932 'Valid modes: ' + str(self.valid_modes))
927 933 else:
928 934 self.mode = mode
929 935 # include variable details only in 'Verbose' mode
930 936 self.include_vars = (self.mode == self.valid_modes[2])
931 937 # Set the join character for generating text tracebacks
932 938 self.tb_join_char = self._join_chars[self.mode]
933 939
934 940 # some convenient shortcuts
935 941 def plain(self):
936 942 self.set_mode(self.valid_modes[0])
937 943
938 944 def context(self):
939 945 self.set_mode(self.valid_modes[1])
940 946
941 947 def verbose(self):
942 948 self.set_mode(self.valid_modes[2])
943 949
944 950 def minimal(self):
945 951 self.set_mode(self.valid_modes[3])
946 952
947 953
948 954 #----------------------------------------------------------------------------
949 955 class AutoFormattedTB(FormattedTB):
950 956 """A traceback printer which can be called on the fly.
951 957
952 958 It will find out about exceptions by itself.
953 959
954 960 A brief example::
955 961
956 962 AutoTB = AutoFormattedTB(mode = 'Verbose',color_scheme='Linux')
957 963 try:
958 964 ...
959 965 except:
960 966 AutoTB() # or AutoTB(out=logfile) where logfile is an open file object
961 967 """
962 968
963 969 def __call__(self, etype=None, evalue=None, etb=None,
964 970 out=None, tb_offset=None):
965 971 """Print out a formatted exception traceback.
966 972
967 973 Optional arguments:
968 974 - out: an open file-like object to direct output to.
969 975
970 976 - tb_offset: the number of frames to skip over in the stack, on a
971 977 per-call basis (this overrides temporarily the instance's tb_offset
972 978 given at initialization time. """
973 979
974 980 if out is None:
975 981 out = self.ostream
976 982 out.flush()
977 983 out.write(self.text(etype, evalue, etb, tb_offset))
978 984 out.write('\n')
979 985 out.flush()
980 986 # FIXME: we should remove the auto pdb behavior from here and leave
981 987 # that to the clients.
982 988 try:
983 989 self.debugger()
984 990 except KeyboardInterrupt:
985 991 print("\nKeyboardInterrupt")
986 992
987 993 def structured_traceback(self, etype=None, value=None, tb=None,
988 994 tb_offset=None, number_of_lines_of_context=5):
989 995 if etype is None:
990 996 etype, value, tb = sys.exc_info()
991 997 if isinstance(tb, tuple):
992 998 # tb is a tuple if this is a chained exception.
993 999 self.tb = tb[0]
994 1000 else:
995 1001 self.tb = tb
996 1002 return FormattedTB.structured_traceback(
997 1003 self, etype, value, tb, tb_offset, number_of_lines_of_context)
998 1004
999 1005
1000 1006 #---------------------------------------------------------------------------
1001 1007
1002 1008 # A simple class to preserve Nathan's original functionality.
1003 1009 class ColorTB(FormattedTB):
1004 1010 """Shorthand to initialize a FormattedTB in Linux colors mode."""
1005 1011
1006 1012 def __init__(self, color_scheme='Linux', call_pdb=0, **kwargs):
1007 1013 FormattedTB.__init__(self, color_scheme=color_scheme,
1008 1014 call_pdb=call_pdb, **kwargs)
1009 1015
1010 1016
1011 1017 class SyntaxTB(ListTB):
1012 1018 """Extension which holds some state: the last exception value"""
1013 1019
1014 1020 def __init__(self, color_scheme='NoColor', parent=None, config=None):
1015 1021 ListTB.__init__(self, color_scheme, parent=parent, config=config)
1016 1022 self.last_syntax_error = None
1017 1023
1018 1024 def __call__(self, etype, value, elist):
1019 1025 self.last_syntax_error = value
1020 1026
1021 1027 ListTB.__call__(self, etype, value, elist)
1022 1028
1023 1029 def structured_traceback(self, etype, value, elist, tb_offset=None,
1024 1030 context=5):
1025 1031 # If the source file has been edited, the line in the syntax error can
1026 1032 # be wrong (retrieved from an outdated cache). This replaces it with
1027 1033 # the current value.
1028 1034 if isinstance(value, SyntaxError) \
1029 1035 and isinstance(value.filename, str) \
1030 1036 and isinstance(value.lineno, int):
1031 1037 linecache.checkcache(value.filename)
1032 1038 newtext = linecache.getline(value.filename, value.lineno)
1033 1039 if newtext:
1034 1040 value.text = newtext
1035 1041 self.last_syntax_error = value
1036 1042 return super(SyntaxTB, self).structured_traceback(etype, value, elist,
1037 1043 tb_offset=tb_offset, context=context)
1038 1044
1039 1045 def clear_err_state(self):
1040 1046 """Return the current error state and clear it"""
1041 1047 e = self.last_syntax_error
1042 1048 self.last_syntax_error = None
1043 1049 return e
1044 1050
1045 1051 def stb2text(self, stb):
1046 1052 """Convert a structured traceback (a list) to a string."""
1047 1053 return ''.join(stb)
1048 1054
1049 1055
1050 1056 # some internal-use functions
1051 1057 def text_repr(value):
1052 1058 """Hopefully pretty robust repr equivalent."""
1053 1059 # this is pretty horrible but should always return *something*
1054 1060 try:
1055 1061 return pydoc.text.repr(value)
1056 1062 except KeyboardInterrupt:
1057 1063 raise
1058 1064 except:
1059 1065 try:
1060 1066 return repr(value)
1061 1067 except KeyboardInterrupt:
1062 1068 raise
1063 1069 except:
1064 1070 try:
1065 1071 # all still in an except block so we catch
1066 1072 # getattr raising
1067 1073 name = getattr(value, '__name__', None)
1068 1074 if name:
1069 1075 # ick, recursion
1070 1076 return text_repr(name)
1071 1077 klass = getattr(value, '__class__', None)
1072 1078 if klass:
1073 1079 return '%s instance' % text_repr(klass)
1074 1080 except KeyboardInterrupt:
1075 1081 raise
1076 1082 except:
1077 1083 return 'UNRECOVERABLE REPR FAILURE'
1078 1084
1079 1085
1080 1086 def eqrepr(value, repr=text_repr):
1081 1087 return '=%s' % repr(value)
1082 1088
1083 1089
1084 1090 def nullrepr(value, repr=text_repr):
1085 1091 return ''
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