summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_traceback.py
blob: c29556354ef49d1b73b6e1793cee1281f3839191 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
"""Test cases for traceback module"""

from io import StringIO
import sys
import unittest
import re
from test.support import run_unittest, Error, captured_output
from test.support import TESTFN, unlink, cpython_only

import traceback


class SyntaxTracebackCases(unittest.TestCase):
    # For now, a very minimal set of tests.  I want to be sure that
    # formatting of SyntaxErrors works based on changes for 2.1.

    def get_exception_format(self, func, exc):
        try:
            func()
        except exc as value:
            return traceback.format_exception_only(exc, value)
        else:
            raise ValueError("call did not raise exception")

    def syntax_error_with_caret(self):
        compile("def fact(x):\n\treturn x!\n", "?", "exec")

    def syntax_error_with_caret_2(self):
        compile("1 +\n", "?", "exec")

    def syntax_error_bad_indentation(self):
        compile("def spam():\n  print(1)\n print(2)", "?", "exec")

    def syntax_error_with_caret_non_ascii(self):
        compile('Python = "\u1e54\xfd\u0163\u0125\xf2\xf1" +', "?", "exec")

    def syntax_error_bad_indentation2(self):
        compile(" print(2)", "?", "exec")

    def test_caret(self):
        err = self.get_exception_format(self.syntax_error_with_caret,
                                        SyntaxError)
        self.assertEqual(len(err), 4)
        self.assertTrue(err[1].strip() == "return x!")
        self.assertIn("^", err[2]) # third line has caret
        self.assertEqual(err[1].find("!"), err[2].find("^")) # in the right place

        err = self.get_exception_format(self.syntax_error_with_caret_2,
                                        SyntaxError)
        self.assertIn("^", err[2]) # third line has caret
        self.assertEqual(err[2].count('\n'), 1)   # and no additional newline
        self.assertEqual(err[1].find("+"), err[2].find("^"))  # in the right place

        err = self.get_exception_format(self.syntax_error_with_caret_non_ascii,
                                        SyntaxError)
        self.assertIn("^", err[2]) # third line has caret
        self.assertEqual(err[2].count('\n'), 1)   # and no additional newline
        self.assertEqual(err[1].find("+"), err[2].find("^"))  # in the right place

    def test_nocaret(self):
        exc = SyntaxError("error", ("x.py", 23, None, "bad syntax"))
        err = traceback.format_exception_only(SyntaxError, exc)
        self.assertEqual(len(err), 3)
        self.assertEqual(err[1].strip(), "bad syntax")

    def test_bad_indentation(self):
        err = self.get_exception_format(self.syntax_error_bad_indentation,
                                        IndentationError)
        self.assertEqual(len(err), 4)
        self.assertEqual(err[1].strip(), "print(2)")
        self.assertIn("^", err[2])
        self.assertEqual(err[1].find(")"), err[2].find("^"))

        err = self.get_exception_format(self.syntax_error_bad_indentation2,
                                        IndentationError)
        self.assertEqual(len(err), 4)
        self.assertEqual(err[1].strip(), "print(2)")
        self.assertIn("^", err[2])
        self.assertEqual(err[1].find("p"), err[2].find("^"))

    def test_base_exception(self):
        # Test that exceptions derived from BaseException are formatted right
        e = KeyboardInterrupt()
        lst = traceback.format_exception_only(e.__class__, e)
        self.assertEqual(lst, ['KeyboardInterrupt\n'])

    def test_format_exception_only_bad__str__(self):
        class X(Exception):
            def __str__(self):
                1/0
        err = traceback.format_exception_only(X, X())
        self.assertEqual(len(err), 1)
        str_value = '<unprintable %s object>' % X.__name__
        if X.__module__ in ('__main__', 'builtins'):
            str_name = X.__name__
        else:
            str_name = '.'.join([X.__module__, X.__name__])
        self.assertEqual(err[0], "%s: %s\n" % (str_name, str_value))

    def test_without_exception(self):
        err = traceback.format_exception_only(None, None)
        self.assertEqual(err, ['None\n'])

    def test_encoded_file(self):
        # Test that tracebacks are correctly printed for encoded source files:
        # - correct line number (Issue2384)
        # - respect file encoding (Issue3975)
        import tempfile, sys, subprocess, os

        # The spawned subprocess has its stdout redirected to a PIPE, and its
        # encoding may be different from the current interpreter, on Windows
        # at least.
        process = subprocess.Popen([sys.executable, "-c",
                                    "import sys; print(sys.stdout.encoding)"],
                                   stdout=subprocess.PIPE,
                                   stderr=subprocess.STDOUT)
        stdout, stderr = process.communicate()
        output_encoding = str(stdout, 'ascii').splitlines()[0]

        def do_test(firstlines, message, charset, lineno):
            # Raise the message in a subprocess, and catch the output
            try:
                output = open(TESTFN, "w", encoding=charset)
                output.write("""{0}if 1:
                    import traceback;
                    raise RuntimeError('{1}')
                    """.format(firstlines, message))
                output.close()
                process = subprocess.Popen([sys.executable, TESTFN],
                    stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
                stdout, stderr = process.communicate()
                stdout = stdout.decode(output_encoding).splitlines()
            finally:
                unlink(TESTFN)

            # The source lines are encoded with the 'backslashreplace' handler
            encoded_message = message.encode(output_encoding,
                                             'backslashreplace')
            # and we just decoded them with the output_encoding.
            message_ascii = encoded_message.decode(output_encoding)

            err_line = "raise RuntimeError('{0}')".format(message_ascii)
            err_msg = "RuntimeError: {0}".format(message_ascii)

            self.assertIn(("line %s" % lineno), stdout[1],
                "Invalid line number: {0!r} instead of {1}".format(
                    stdout[1], lineno))
            self.assertTrue(stdout[2].endswith(err_line),
                "Invalid traceback line: {0!r} instead of {1!r}".format(
                    stdout[2], err_line))
            self.assertTrue(stdout[3] == err_msg,
                "Invalid error message: {0!r} instead of {1!r}".format(
                    stdout[3], err_msg))

        do_test("", "foo", "ascii", 3)
        for charset in ("ascii", "iso-8859-1", "utf-8", "GBK"):
            if charset == "ascii":
                text = "foo"
            elif charset == "GBK":
                text = "\u4E02\u5100"
            else:
                text = "h\xe9 ho"
            do_test("# coding: {0}\n".format(charset),
                    text, charset, 4)
            do_test("#!shebang\n# coding: {0}\n".format(charset),
                    text, charset, 5)
            do_test(" \t\f\n# coding: {0}\n".format(charset),
                    text, charset, 5)
        # Issue #18960: coding spec should has no effect
        do_test("0\n# coding: GBK\n", "h\xe9 ho", 'utf-8', 5)


class TracebackFormatTests(unittest.TestCase):

    def some_exception(self):
        raise KeyError('blah')

    @cpython_only
    def check_traceback_format(self, cleanup_func=None):
        from _testcapi import traceback_print
        try:
            self.some_exception()
        except KeyError:
            type_, value, tb = sys.exc_info()
            if cleanup_func is not None:
                # Clear the inner frames, not this one
                cleanup_func(tb.tb_next)
            traceback_fmt = 'Traceback (most recent call last):\n' + \
                            ''.join(traceback.format_tb(tb))
            file_ = StringIO()
            traceback_print(tb, file_)
            python_fmt  = file_.getvalue()
            # Call all _tb and _exc functions
            with captured_output("stderr") as tbstderr:
                traceback.print_tb(tb)
            tbfile = StringIO()
            traceback.print_tb(tb, file=tbfile)
            with captured_output("stderr") as excstderr:
                traceback.print_exc()
            excfmt = traceback.format_exc()
            excfile = StringIO()
            traceback.print_exc(file=excfile)
        else:
            raise Error("unable to create test traceback string")

        # Make sure that Python and the traceback module format the same thing
        self.assertEqual(traceback_fmt, python_fmt)
        # Now verify the _tb func output
        self.assertEqual(tbstderr.getvalue(), tbfile.getvalue())
        # Now verify the _exc func output
        self.assertEqual(excstderr.getvalue(), excfile.getvalue())
        self.assertEqual(excfmt, excfile.getvalue())

        # Make sure that the traceback is properly indented.
        tb_lines = python_fmt.splitlines()
        self.assertEqual(len(tb_lines), 5)
        banner = tb_lines[0]
        location, source_line = tb_lines[-2:]
        self.assertTrue(banner.startswith('Traceback'))
        self.assertTrue(location.startswith('  File'))
        self.assertTrue(source_line.startswith('    raise'))

    def test_traceback_format(self):
        self.check_traceback_format()

    def test_traceback_format_with_cleared_frames(self):
        # Check that traceback formatting also works with a clear()ed frame
        def cleanup_tb(tb):
            tb.tb_frame.clear()
        self.check_traceback_format(cleanup_tb)

    def test_stack_format(self):
        # Verify _stack functions. Note we have to use _getframe(1) to
        # compare them without this frame appearing in the output
        with captured_output("stderr") as ststderr:
            traceback.print_stack(sys._getframe(1))
        stfile = StringIO()
        traceback.print_stack(sys._getframe(1), file=stfile)
        self.assertEqual(ststderr.getvalue(), stfile.getvalue())

        stfmt = traceback.format_stack(sys._getframe(1))

        self.assertEqual(ststderr.getvalue(), "".join(stfmt))


cause_message = (
    "\nThe above exception was the direct cause "
    "of the following exception:\n\n")

context_message = (
    "\nDuring handling of the above exception, "
    "another exception occurred:\n\n")

boundaries = re.compile(
    '(%s|%s)' % (re.escape(cause_message), re.escape(context_message)))


class BaseExceptionReportingTests:

    def get_exception(self, exception_or_callable):
        if isinstance(exception_or_callable, Exception):
            return exception_or_callable
        try:
            exception_or_callable()
        except Exception as e:
            return e

    def zero_div(self):
        1/0 # In zero_div

    def check_zero_div(self, msg):
        lines = msg.splitlines()
        self.assertTrue(lines[-3].startswith('  File'))
        self.assertIn('1/0 # In zero_div', lines[-2])
        self.assertTrue(lines[-1].startswith('ZeroDivisionError'), lines[-1])

    def test_simple(self):
        try:
            1/0 # Marker
        except ZeroDivisionError as _:
            e = _
        lines = self.get_report(e).splitlines()
        self.assertEqual(len(lines), 4)
        self.assertTrue(lines[0].startswith('Traceback'))
        self.assertTrue(lines[1].startswith('  File'))
        self.assertIn('1/0 # Marker', lines[2])
        self.assertTrue(lines[3].startswith('ZeroDivisionError'))

    def test_cause(self):
        def inner_raise():
            try:
                self.zero_div()
            except ZeroDivisionError as e:
                raise KeyError from e
        def outer_raise():
            inner_raise() # Marker
        blocks = boundaries.split(self.get_report(outer_raise))
        self.assertEqual(len(blocks), 3)
        self.assertEqual(blocks[1], cause_message)
        self.check_zero_div(blocks[0])
        self.assertIn('inner_raise() # Marker', blocks[2])

    def test_context(self):
        def inner_raise():
            try:
                self.zero_div()
            except ZeroDivisionError:
                raise KeyError
        def outer_raise():
            inner_raise() # Marker
        blocks = boundaries.split(self.get_report(outer_raise))
        self.assertEqual(len(blocks), 3)
        self.assertEqual(blocks[1], context_message)
        self.check_zero_div(blocks[0])
        self.assertIn('inner_raise() # Marker', blocks[2])

    def test_context_suppression(self):
        try:
            try:
                raise Exception
            except:
                raise ZeroDivisionError from None
        except ZeroDivisionError as _:
            e = _
        lines = self.get_report(e).splitlines()
        self.assertEqual(len(lines), 4)
        self.assertTrue(lines[0].startswith('Traceback'))
        self.assertTrue(lines[1].startswith('  File'))
        self.assertIn('ZeroDivisionError from None', lines[2])
        self.assertTrue(lines[3].startswith('ZeroDivisionError'))

    def test_cause_and_context(self):
        # When both a cause and a context are set, only the cause should be
        # displayed and the context should be muted.
        def inner_raise():
            try:
                self.zero_div()
            except ZeroDivisionError as _e:
                e = _e
            try:
                xyzzy
            except NameError:
                raise KeyError from e
        def outer_raise():
            inner_raise() # Marker
        blocks = boundaries.split(self.get_report(outer_raise))
        self.assertEqual(len(blocks), 3)
        self.assertEqual(blocks[1], cause_message)
        self.check_zero_div(blocks[0])
        self.assertIn('inner_raise() # Marker', blocks[2])

    def test_cause_recursive(self):
        def inner_raise():
            try:
                try:
                    self.zero_div()
                except ZeroDivisionError as e:
                    z = e
                    raise KeyError from e
            except KeyError as e:
                raise z from e
        def outer_raise():
            inner_raise() # Marker
        blocks = boundaries.split(self.get_report(outer_raise))
        self.assertEqual(len(blocks), 3)
        self.assertEqual(blocks[1], cause_message)
        # The first block is the KeyError raised from the ZeroDivisionError
        self.assertIn('raise KeyError from e', blocks[0])
        self.assertNotIn('1/0', blocks[0])
        # The second block (apart from the boundary) is the ZeroDivisionError
        # re-raised from the KeyError
        self.assertIn('inner_raise() # Marker', blocks[2])
        self.check_zero_div(blocks[2])

    def test_syntax_error_offset_at_eol(self):
        # See #10186.
        def e():
            raise SyntaxError('', ('', 0, 5, 'hello'))
        msg = self.get_report(e).splitlines()
        self.assertEqual(msg[-2], "        ^")
        def e():
            exec("x = 5 | 4 |")
        msg = self.get_report(e).splitlines()
        self.assertEqual(msg[-2], '              ^')


class PyExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
    #
    # This checks reporting through the 'traceback' module, with both
    # format_exception() and print_exception().
    #

    def get_report(self, e):
        e = self.get_exception(e)
        s = ''.join(
            traceback.format_exception(type(e), e, e.__traceback__))
        with captured_output("stderr") as sio:
            traceback.print_exception(type(e), e, e.__traceback__)
        self.assertEqual(sio.getvalue(), s)
        return s


class CExcReportingTests(BaseExceptionReportingTests, unittest.TestCase):
    #
    # This checks built-in reporting by the interpreter.
    #

    @cpython_only
    def get_report(self, e):
        from _testcapi import exception_print
        e = self.get_exception(e)
        with captured_output("stderr") as s:
            exception_print(e)
        return s.getvalue()


class MiscTracebackCases(unittest.TestCase):
    #
    # Check non-printing functions in traceback module
    #

    def test_clear(self):
        def outer():
            middle()
        def middle():
            inner()
        def inner():
            i = 1
            1/0

        try:
            outer()
        except:
            type_, value, tb = sys.exc_info()

        # Initial assertion: there's one local in the inner frame.
        inner_frame = tb.tb_next.tb_next.tb_next.tb_frame
        self.assertEqual(len(inner_frame.f_locals), 1)

        # Clear traceback frames
        traceback.clear_frames(tb)

        # Local variable dict should now be empty.
        self.assertEqual(len(inner_frame.f_locals), 0)


def test_main():
    run_unittest(__name__)

if __name__ == "__main__":
    test_main()