gh-97008: Add a Python implementation of AttributeError and NameError suggestions (#97022)

Relevant tests moved from test_exceptions to test_traceback to be able to
compare both implementations.

Co-authored-by: Carl Friedrich Bolz-Tereick <cfbolz@gmx.de>
This commit is contained in:
Łukasz Langa 2022-10-04 15:31:16 -07:00 committed by GitHub
parent 7acb93f0d4
commit bbc7cd649a
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GPG Key ID: 4AEE18F83AFDEB23
8 changed files with 50707 additions and 520 deletions

1
.gitattributes vendored
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@ -73,6 +73,7 @@ Include/internal/pycore_runtime_init_generated.h generated
Include/opcode.h generated
Include/token.h generated
Lib/keyword.py generated
Lib/test/levenshtein_examples.json generated
Lib/test/test_stable_abi_ctypes.py generated
Lib/token.py generated
Objects/typeslots.inc generated

50002
Lib/test/levenshtein_examples.json generated Normal file

File diff suppressed because it is too large Load Diff

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@ -1770,7 +1770,6 @@ class ExceptionTests(unittest.TestCase):
gc_collect()
global_for_suggestions = None
class NameErrorTests(unittest.TestCase):
def test_name_error_has_name(self):
@ -1779,272 +1778,6 @@ class NameErrorTests(unittest.TestCase):
except NameError as exc:
self.assertEqual("bluch", exc.name)
def test_name_error_suggestions(self):
def Substitution():
noise = more_noise = a = bc = None
blech = None
print(bluch)
def Elimination():
noise = more_noise = a = bc = None
blch = None
print(bluch)
def Addition():
noise = more_noise = a = bc = None
bluchin = None
print(bluch)
def SubstitutionOverElimination():
blach = None
bluc = None
print(bluch)
def SubstitutionOverAddition():
blach = None
bluchi = None
print(bluch)
def EliminationOverAddition():
blucha = None
bluc = None
print(bluch)
for func, suggestion in [(Substitution, "'blech'?"),
(Elimination, "'blch'?"),
(Addition, "'bluchin'?"),
(EliminationOverAddition, "'blucha'?"),
(SubstitutionOverElimination, "'blach'?"),
(SubstitutionOverAddition, "'blach'?")]:
err = None
try:
func()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn(suggestion, err.getvalue())
def test_name_error_suggestions_from_globals(self):
def func():
print(global_for_suggestio)
try:
func()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn("'global_for_suggestions'?", err.getvalue())
def test_name_error_suggestions_from_builtins(self):
def func():
print(ZeroDivisionErrrrr)
try:
func()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn("'ZeroDivisionError'?", err.getvalue())
def test_name_error_suggestions_do_not_trigger_for_long_names(self):
def f():
somethingverywronghehehehehehe = None
print(somethingverywronghe)
try:
f()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("somethingverywronghehe", err.getvalue())
def test_name_error_bad_suggestions_do_not_trigger_for_small_names(self):
vvv = mom = w = id = pytho = None
with self.subTest(name="b"):
try:
b
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
with self.subTest(name="v"):
try:
v
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
with self.subTest(name="m"):
try:
m
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
with self.subTest(name="py"):
try:
py
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
def test_name_error_suggestions_do_not_trigger_for_too_many_locals(self):
def f():
# Mutating locals() is unreliable, so we need to do it by hand
a1 = a2 = a3 = a4 = a5 = a6 = a7 = a8 = a9 = a10 = \
a11 = a12 = a13 = a14 = a15 = a16 = a17 = a18 = a19 = a20 = \
a21 = a22 = a23 = a24 = a25 = a26 = a27 = a28 = a29 = a30 = \
a31 = a32 = a33 = a34 = a35 = a36 = a37 = a38 = a39 = a40 = \
a41 = a42 = a43 = a44 = a45 = a46 = a47 = a48 = a49 = a50 = \
a51 = a52 = a53 = a54 = a55 = a56 = a57 = a58 = a59 = a60 = \
a61 = a62 = a63 = a64 = a65 = a66 = a67 = a68 = a69 = a70 = \
a71 = a72 = a73 = a74 = a75 = a76 = a77 = a78 = a79 = a80 = \
a81 = a82 = a83 = a84 = a85 = a86 = a87 = a88 = a89 = a90 = \
a91 = a92 = a93 = a94 = a95 = a96 = a97 = a98 = a99 = a100 = \
a101 = a102 = a103 = a104 = a105 = a106 = a107 = a108 = a109 = a110 = \
a111 = a112 = a113 = a114 = a115 = a116 = a117 = a118 = a119 = a120 = \
a121 = a122 = a123 = a124 = a125 = a126 = a127 = a128 = a129 = a130 = \
a131 = a132 = a133 = a134 = a135 = a136 = a137 = a138 = a139 = a140 = \
a141 = a142 = a143 = a144 = a145 = a146 = a147 = a148 = a149 = a150 = \
a151 = a152 = a153 = a154 = a155 = a156 = a157 = a158 = a159 = a160 = \
a161 = a162 = a163 = a164 = a165 = a166 = a167 = a168 = a169 = a170 = \
a171 = a172 = a173 = a174 = a175 = a176 = a177 = a178 = a179 = a180 = \
a181 = a182 = a183 = a184 = a185 = a186 = a187 = a188 = a189 = a190 = \
a191 = a192 = a193 = a194 = a195 = a196 = a197 = a198 = a199 = a200 = \
a201 = a202 = a203 = a204 = a205 = a206 = a207 = a208 = a209 = a210 = \
a211 = a212 = a213 = a214 = a215 = a216 = a217 = a218 = a219 = a220 = \
a221 = a222 = a223 = a224 = a225 = a226 = a227 = a228 = a229 = a230 = \
a231 = a232 = a233 = a234 = a235 = a236 = a237 = a238 = a239 = a240 = \
a241 = a242 = a243 = a244 = a245 = a246 = a247 = a248 = a249 = a250 = \
a251 = a252 = a253 = a254 = a255 = a256 = a257 = a258 = a259 = a260 = \
a261 = a262 = a263 = a264 = a265 = a266 = a267 = a268 = a269 = a270 = \
a271 = a272 = a273 = a274 = a275 = a276 = a277 = a278 = a279 = a280 = \
a281 = a282 = a283 = a284 = a285 = a286 = a287 = a288 = a289 = a290 = \
a291 = a292 = a293 = a294 = a295 = a296 = a297 = a298 = a299 = a300 = \
a301 = a302 = a303 = a304 = a305 = a306 = a307 = a308 = a309 = a310 = \
a311 = a312 = a313 = a314 = a315 = a316 = a317 = a318 = a319 = a320 = \
a321 = a322 = a323 = a324 = a325 = a326 = a327 = a328 = a329 = a330 = \
a331 = a332 = a333 = a334 = a335 = a336 = a337 = a338 = a339 = a340 = \
a341 = a342 = a343 = a344 = a345 = a346 = a347 = a348 = a349 = a350 = \
a351 = a352 = a353 = a354 = a355 = a356 = a357 = a358 = a359 = a360 = \
a361 = a362 = a363 = a364 = a365 = a366 = a367 = a368 = a369 = a370 = \
a371 = a372 = a373 = a374 = a375 = a376 = a377 = a378 = a379 = a380 = \
a381 = a382 = a383 = a384 = a385 = a386 = a387 = a388 = a389 = a390 = \
a391 = a392 = a393 = a394 = a395 = a396 = a397 = a398 = a399 = a400 = \
a401 = a402 = a403 = a404 = a405 = a406 = a407 = a408 = a409 = a410 = \
a411 = a412 = a413 = a414 = a415 = a416 = a417 = a418 = a419 = a420 = \
a421 = a422 = a423 = a424 = a425 = a426 = a427 = a428 = a429 = a430 = \
a431 = a432 = a433 = a434 = a435 = a436 = a437 = a438 = a439 = a440 = \
a441 = a442 = a443 = a444 = a445 = a446 = a447 = a448 = a449 = a450 = \
a451 = a452 = a453 = a454 = a455 = a456 = a457 = a458 = a459 = a460 = \
a461 = a462 = a463 = a464 = a465 = a466 = a467 = a468 = a469 = a470 = \
a471 = a472 = a473 = a474 = a475 = a476 = a477 = a478 = a479 = a480 = \
a481 = a482 = a483 = a484 = a485 = a486 = a487 = a488 = a489 = a490 = \
a491 = a492 = a493 = a494 = a495 = a496 = a497 = a498 = a499 = a500 = \
a501 = a502 = a503 = a504 = a505 = a506 = a507 = a508 = a509 = a510 = \
a511 = a512 = a513 = a514 = a515 = a516 = a517 = a518 = a519 = a520 = \
a521 = a522 = a523 = a524 = a525 = a526 = a527 = a528 = a529 = a530 = \
a531 = a532 = a533 = a534 = a535 = a536 = a537 = a538 = a539 = a540 = \
a541 = a542 = a543 = a544 = a545 = a546 = a547 = a548 = a549 = a550 = \
a551 = a552 = a553 = a554 = a555 = a556 = a557 = a558 = a559 = a560 = \
a561 = a562 = a563 = a564 = a565 = a566 = a567 = a568 = a569 = a570 = \
a571 = a572 = a573 = a574 = a575 = a576 = a577 = a578 = a579 = a580 = \
a581 = a582 = a583 = a584 = a585 = a586 = a587 = a588 = a589 = a590 = \
a591 = a592 = a593 = a594 = a595 = a596 = a597 = a598 = a599 = a600 = \
a601 = a602 = a603 = a604 = a605 = a606 = a607 = a608 = a609 = a610 = \
a611 = a612 = a613 = a614 = a615 = a616 = a617 = a618 = a619 = a620 = \
a621 = a622 = a623 = a624 = a625 = a626 = a627 = a628 = a629 = a630 = \
a631 = a632 = a633 = a634 = a635 = a636 = a637 = a638 = a639 = a640 = \
a641 = a642 = a643 = a644 = a645 = a646 = a647 = a648 = a649 = a650 = \
a651 = a652 = a653 = a654 = a655 = a656 = a657 = a658 = a659 = a660 = \
a661 = a662 = a663 = a664 = a665 = a666 = a667 = a668 = a669 = a670 = \
a671 = a672 = a673 = a674 = a675 = a676 = a677 = a678 = a679 = a680 = \
a681 = a682 = a683 = a684 = a685 = a686 = a687 = a688 = a689 = a690 = \
a691 = a692 = a693 = a694 = a695 = a696 = a697 = a698 = a699 = a700 = \
a701 = a702 = a703 = a704 = a705 = a706 = a707 = a708 = a709 = a710 = \
a711 = a712 = a713 = a714 = a715 = a716 = a717 = a718 = a719 = a720 = \
a721 = a722 = a723 = a724 = a725 = a726 = a727 = a728 = a729 = a730 = \
a731 = a732 = a733 = a734 = a735 = a736 = a737 = a738 = a739 = a740 = \
a741 = a742 = a743 = a744 = a745 = a746 = a747 = a748 = a749 = a750 = \
a751 = a752 = a753 = a754 = a755 = a756 = a757 = a758 = a759 = a760 = \
a761 = a762 = a763 = a764 = a765 = a766 = a767 = a768 = a769 = a770 = \
a771 = a772 = a773 = a774 = a775 = a776 = a777 = a778 = a779 = a780 = \
a781 = a782 = a783 = a784 = a785 = a786 = a787 = a788 = a789 = a790 = \
a791 = a792 = a793 = a794 = a795 = a796 = a797 = a798 = a799 = a800 \
= None
print(a0)
try:
f()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotRegex(err.getvalue(), r"NameError.*a1")
def test_name_error_with_custom_exceptions(self):
def f():
blech = None
raise NameError()
try:
f()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("blech", err.getvalue())
def f():
blech = None
raise NameError
try:
f()
except NameError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("blech", err.getvalue())
def test_unbound_local_error_doesn_not_match(self):
def foo():
something = 3
print(somethong)
somethong = 3
try:
foo()
except UnboundLocalError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("something", err.getvalue())
def test_issue45826(self):
# regression test for bpo-45826
def f():
@ -2076,6 +1809,8 @@ class NameErrorTests(unittest.TestCase):
self.assertIn("nonsense", err.getvalue())
self.assertIn("ZeroDivisionError", err.getvalue())
# Note: name suggestion tests live in `test_traceback`.
class AttributeErrorTests(unittest.TestCase):
def test_attributes(self):
@ -2117,239 +1852,7 @@ class AttributeErrorTests(unittest.TestCase):
self.assertEqual("bluch", exc.name)
self.assertEqual(obj, exc.obj)
def test_getattr_suggestions(self):
class Substitution:
noise = more_noise = a = bc = None
blech = None
class Elimination:
noise = more_noise = a = bc = None
blch = None
class Addition:
noise = more_noise = a = bc = None
bluchin = None
class SubstitutionOverElimination:
blach = None
bluc = None
class SubstitutionOverAddition:
blach = None
bluchi = None
class EliminationOverAddition:
blucha = None
bluc = None
for cls, suggestion in [(Substitution, "'blech'?"),
(Elimination, "'blch'?"),
(Addition, "'bluchin'?"),
(EliminationOverAddition, "'bluc'?"),
(SubstitutionOverElimination, "'blach'?"),
(SubstitutionOverAddition, "'blach'?")]:
try:
cls().bluch
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn(suggestion, err.getvalue())
def test_getattr_suggestions_do_not_trigger_for_long_attributes(self):
class A:
blech = None
try:
A().somethingverywrong
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("blech", err.getvalue())
def test_getattr_error_bad_suggestions_do_not_trigger_for_small_names(self):
class MyClass:
vvv = mom = w = id = pytho = None
with self.subTest(name="b"):
try:
MyClass.b
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
with self.subTest(name="v"):
try:
MyClass.v
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
with self.subTest(name="m"):
try:
MyClass.m
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
with self.subTest(name="py"):
try:
MyClass.py
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("you mean", err.getvalue())
self.assertNotIn("vvv", err.getvalue())
self.assertNotIn("mom", err.getvalue())
self.assertNotIn("'id'", err.getvalue())
self.assertNotIn("'w'", err.getvalue())
self.assertNotIn("'pytho'", err.getvalue())
def test_getattr_suggestions_do_not_trigger_for_big_dicts(self):
class A:
blech = None
# A class with a very big __dict__ will not be consider
# for suggestions.
for index in range(2000):
setattr(A, f"index_{index}", None)
try:
A().bluch
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("blech", err.getvalue())
def test_getattr_suggestions_no_args(self):
class A:
blech = None
def __getattr__(self, attr):
raise AttributeError()
try:
A().bluch
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn("blech", err.getvalue())
class A:
blech = None
def __getattr__(self, attr):
raise AttributeError
try:
A().bluch
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn("blech", err.getvalue())
def test_getattr_suggestions_invalid_args(self):
class NonStringifyClass:
__str__ = None
__repr__ = None
class A:
blech = None
def __getattr__(self, attr):
raise AttributeError(NonStringifyClass())
class B:
blech = None
def __getattr__(self, attr):
raise AttributeError("Error", 23)
class C:
blech = None
def __getattr__(self, attr):
raise AttributeError(23)
for cls in [A, B, C]:
try:
cls().bluch
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn("blech", err.getvalue())
def test_getattr_suggestions_for_same_name(self):
class A:
def __dir__(self):
return ['blech']
try:
A().blech
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("Did you mean", err.getvalue())
def test_attribute_error_with_failing_dict(self):
class T:
bluch = 1
def __dir__(self):
raise AttributeError("oh no!")
try:
T().blich
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("blech", err.getvalue())
self.assertNotIn("oh no!", err.getvalue())
def test_attribute_error_with_bad_name(self):
try:
raise AttributeError(name=12, obj=23)
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertNotIn("?", err.getvalue())
def test_attribute_error_inside_nested_getattr(self):
class A:
bluch = 1
class B:
def __getattribute__(self, attr):
a = A()
return a.blich
try:
B().something
except AttributeError as exc:
with support.captured_stderr() as err:
sys.__excepthook__(*sys.exc_info())
self.assertIn("Did you mean", err.getvalue())
self.assertIn("bluch", err.getvalue())
# Note: name suggestion tests live in `test_traceback`.
class ImportErrorTests(unittest.TestCase):

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@ -15,9 +15,11 @@ from test.support import (Error, captured_output, cpython_only, ALWAYS_EQ,
from test.support.os_helper import TESTFN, unlink
from test.support.script_helper import assert_python_ok, assert_python_failure
import json
import textwrap
import traceback
from functools import partial
from pathlib import Path
MODULE_PREFIX = f'{__name__}.' if __name__ == '__main__' else ''
@ -27,6 +29,9 @@ test_frame = namedtuple('frame', ['f_code', 'f_globals', 'f_locals'])
test_tb = namedtuple('tb', ['tb_frame', 'tb_lineno', 'tb_next', 'tb_lasti'])
LEVENSHTEIN_DATA_FILE = Path(__file__).parent / 'levenshtein_examples.json'
class TracebackCases(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.
@ -371,20 +376,36 @@ class TracebackCases(unittest.TestCase):
'(exc, /, value=<implicit>)')
@requires_debug_ranges()
class TracebackErrorLocationCaretTests(unittest.TestCase):
"""
Tests for printing code error expressions as part of PEP 657
"""
def get_exception(self, callable):
class PurePythonExceptionFormattingMixin:
def get_exception(self, callable, slice_start=0, slice_end=-1):
try:
callable()
self.fail("No exception thrown.")
except:
return traceback.format_exc().splitlines()[:-1]
return traceback.format_exc().splitlines()[slice_start:slice_end]
callable_line = get_exception.__code__.co_firstlineno + 2
class CAPIExceptionFormattingMixin:
def get_exception(self, callable, slice_start=0, slice_end=-1):
from _testcapi import exception_print
try:
callable()
self.fail("No exception thrown.")
except Exception as e:
with captured_output("stderr") as tbstderr:
exception_print(e)
return tbstderr.getvalue().splitlines()[slice_start:slice_end]
callable_line = get_exception.__code__.co_firstlineno + 3
@requires_debug_ranges()
class TracebackErrorLocationCaretTestBase:
"""
Tests for printing code error expressions as part of PEP 657
"""
def test_basic_caret(self):
# NOTE: In caret tests, "if True:" is used as a way to force indicator
# display, since the raising expression spans only part of the line.
@ -777,23 +798,29 @@ class TracebackErrorLocationCaretTests(unittest.TestCase):
]
self.assertEqual(actual, expected)
@requires_debug_ranges()
class PurePythonTracebackErrorCaretTests(
PurePythonExceptionFormattingMixin,
TracebackErrorLocationCaretTestBase,
unittest.TestCase,
):
"""
Same set of tests as above using the pure Python implementation of
traceback printing in traceback.py.
"""
@cpython_only
@requires_debug_ranges()
class CPythonTracebackErrorCaretTests(TracebackErrorLocationCaretTests):
class CPythonTracebackErrorCaretTests(
CAPIExceptionFormattingMixin,
TracebackErrorLocationCaretTestBase,
unittest.TestCase,
):
"""
Same set of tests as above but with Python's internal traceback printing.
"""
def get_exception(self, callable):
from _testcapi import exception_print
try:
callable()
self.fail("No exception thrown.")
except Exception as e:
with captured_output("stderr") as tbstderr:
exception_print(e)
return tbstderr.getvalue().splitlines()[:-1]
callable_line = get_exception.__code__.co_firstlineno + 3
class TracebackFormatTests(unittest.TestCase):
@ -2787,6 +2814,400 @@ class TestTracebackException_ExceptionGroups(unittest.TestCase):
self.assertEqual(exc, ALWAYS_EQ)
global_for_suggestions = None
class SuggestionFormattingTestBase:
def get_suggestion(self, obj, attr_name=None):
if attr_name is not None:
def callable():
getattr(obj, attr_name)
else:
callable = obj
result_lines = self.get_exception(
callable, slice_start=-1, slice_end=None
)
return result_lines[0]
def test_getattr_suggestions(self):
class Substitution:
noise = more_noise = a = bc = None
blech = None
class Elimination:
noise = more_noise = a = bc = None
blch = None
class Addition:
noise = more_noise = a = bc = None
bluchin = None
class SubstitutionOverElimination:
blach = None
bluc = None
class SubstitutionOverAddition:
blach = None
bluchi = None
class EliminationOverAddition:
blucha = None
bluc = None
class CaseChangeOverSubstitution:
Luch = None
fluch = None
BLuch = None
for cls, suggestion in [
(Addition, "'bluchin'?"),
(Substitution, "'blech'?"),
(Elimination, "'blch'?"),
(Addition, "'bluchin'?"),
(SubstitutionOverElimination, "'blach'?"),
(SubstitutionOverAddition, "'blach'?"),
(EliminationOverAddition, "'bluc'?"),
(CaseChangeOverSubstitution, "'BLuch'?"),
]:
actual = self.get_suggestion(cls(), 'bluch')
self.assertIn(suggestion, actual)
def test_getattr_suggestions_do_not_trigger_for_long_attributes(self):
class A:
blech = None
actual = self.get_suggestion(A(), 'somethingverywrong')
self.assertNotIn("blech", actual)
def test_getattr_error_bad_suggestions_do_not_trigger_for_small_names(self):
class MyClass:
vvv = mom = w = id = pytho = None
for name in ("b", "v", "m", "py"):
with self.subTest(name=name):
actual = self.get_suggestion(MyClass, name)
self.assertNotIn("you mean", actual)
self.assertNotIn("vvv", actual)
self.assertNotIn("mom", actual)
self.assertNotIn("'id'", actual)
self.assertNotIn("'w'", actual)
self.assertNotIn("'pytho'", actual)
def test_getattr_suggestions_do_not_trigger_for_big_dicts(self):
class A:
blech = None
# A class with a very big __dict__ will not be consider
# for suggestions.
for index in range(2000):
setattr(A, f"index_{index}", None)
actual = self.get_suggestion(A(), 'bluch')
self.assertNotIn("blech", actual)
def test_getattr_suggestions_no_args(self):
class A:
blech = None
def __getattr__(self, attr):
raise AttributeError()
actual = self.get_suggestion(A(), 'bluch')
self.assertIn("blech", actual)
class A:
blech = None
def __getattr__(self, attr):
raise AttributeError
actual = self.get_suggestion(A(), 'bluch')
self.assertIn("blech", actual)
def test_getattr_suggestions_invalid_args(self):
class NonStringifyClass:
__str__ = None
__repr__ = None
class A:
blech = None
def __getattr__(self, attr):
raise AttributeError(NonStringifyClass())
class B:
blech = None
def __getattr__(self, attr):
raise AttributeError("Error", 23)
class C:
blech = None
def __getattr__(self, attr):
raise AttributeError(23)
for cls in [A, B, C]:
actual = self.get_suggestion(cls(), 'bluch')
self.assertIn("blech", actual)
def test_getattr_suggestions_for_same_name(self):
class A:
def __dir__(self):
return ['blech']
actual = self.get_suggestion(A(), 'blech')
self.assertNotIn("Did you mean", actual)
def test_attribute_error_with_failing_dict(self):
class T:
bluch = 1
def __dir__(self):
raise AttributeError("oh no!")
actual = self.get_suggestion(T(), 'blich')
self.assertNotIn("blech", actual)
self.assertNotIn("oh no!", actual)
def test_attribute_error_with_bad_name(self):
def raise_attribute_error_with_bad_name():
raise AttributeError(name=12, obj=23)
result_lines = self.get_exception(
raise_attribute_error_with_bad_name, slice_start=-1, slice_end=None
)
self.assertNotIn("?", result_lines[-1])
def test_attribute_error_inside_nested_getattr(self):
class A:
bluch = 1
class B:
def __getattribute__(self, attr):
a = A()
return a.blich
actual = self.get_suggestion(B(), 'something')
self.assertIn("Did you mean", actual)
self.assertIn("bluch", actual)
def test_name_error_suggestions(self):
def Substitution():
noise = more_noise = a = bc = None
blech = None
print(bluch)
def Elimination():
noise = more_noise = a = bc = None
blch = None
print(bluch)
def Addition():
noise = more_noise = a = bc = None
bluchin = None
print(bluch)
def SubstitutionOverElimination():
blach = None
bluc = None
print(bluch)
def SubstitutionOverAddition():
blach = None
bluchi = None
print(bluch)
def EliminationOverAddition():
blucha = None
bluc = None
print(bluch)
for func, suggestion in [(Substitution, "'blech'?"),
(Elimination, "'blch'?"),
(Addition, "'bluchin'?"),
(EliminationOverAddition, "'blucha'?"),
(SubstitutionOverElimination, "'blach'?"),
(SubstitutionOverAddition, "'blach'?")]:
actual = self.get_suggestion(func)
self.assertIn(suggestion, actual)
def test_name_error_suggestions_from_globals(self):
def func():
print(global_for_suggestio)
actual = self.get_suggestion(func)
self.assertIn("'global_for_suggestions'?", actual)
def test_name_error_suggestions_from_builtins(self):
def func():
print(ZeroDivisionErrrrr)
actual = self.get_suggestion(func)
self.assertIn("'ZeroDivisionError'?", actual)
def test_name_error_suggestions_do_not_trigger_for_long_names(self):
def func():
somethingverywronghehehehehehe = None
print(somethingverywronghe)
actual = self.get_suggestion(func)
self.assertNotIn("somethingverywronghehe", actual)
def test_name_error_bad_suggestions_do_not_trigger_for_small_names(self):
def f_b():
vvv = mom = w = id = pytho = None
b
def f_v():
vvv = mom = w = id = pytho = None
v
def f_m():
vvv = mom = w = id = pytho = None
m
def f_py():
vvv = mom = w = id = pytho = None
py
for name, func in (("b", f_b), ("v", f_v), ("m", f_m), ("py", f_py)):
with self.subTest(name=name):
actual = self.get_suggestion(func)
self.assertNotIn("you mean", actual)
self.assertNotIn("vvv", actual)
self.assertNotIn("mom", actual)
self.assertNotIn("'id'", actual)
self.assertNotIn("'w'", actual)
self.assertNotIn("'pytho'", actual)
def test_name_error_suggestions_do_not_trigger_for_too_many_locals(self):
def func():
# Mutating locals() is unreliable, so we need to do it by hand
a1 = a2 = a3 = a4 = a5 = a6 = a7 = a8 = a9 = a10 = \
a11 = a12 = a13 = a14 = a15 = a16 = a17 = a18 = a19 = a20 = \
a21 = a22 = a23 = a24 = a25 = a26 = a27 = a28 = a29 = a30 = \
a31 = a32 = a33 = a34 = a35 = a36 = a37 = a38 = a39 = a40 = \
a41 = a42 = a43 = a44 = a45 = a46 = a47 = a48 = a49 = a50 = \
a51 = a52 = a53 = a54 = a55 = a56 = a57 = a58 = a59 = a60 = \
a61 = a62 = a63 = a64 = a65 = a66 = a67 = a68 = a69 = a70 = \
a71 = a72 = a73 = a74 = a75 = a76 = a77 = a78 = a79 = a80 = \
a81 = a82 = a83 = a84 = a85 = a86 = a87 = a88 = a89 = a90 = \
a91 = a92 = a93 = a94 = a95 = a96 = a97 = a98 = a99 = a100 = \
a101 = a102 = a103 = a104 = a105 = a106 = a107 = a108 = a109 = a110 = \
a111 = a112 = a113 = a114 = a115 = a116 = a117 = a118 = a119 = a120 = \
a121 = a122 = a123 = a124 = a125 = a126 = a127 = a128 = a129 = a130 = \
a131 = a132 = a133 = a134 = a135 = a136 = a137 = a138 = a139 = a140 = \
a141 = a142 = a143 = a144 = a145 = a146 = a147 = a148 = a149 = a150 = \
a151 = a152 = a153 = a154 = a155 = a156 = a157 = a158 = a159 = a160 = \
a161 = a162 = a163 = a164 = a165 = a166 = a167 = a168 = a169 = a170 = \
a171 = a172 = a173 = a174 = a175 = a176 = a177 = a178 = a179 = a180 = \
a181 = a182 = a183 = a184 = a185 = a186 = a187 = a188 = a189 = a190 = \
a191 = a192 = a193 = a194 = a195 = a196 = a197 = a198 = a199 = a200 = \
a201 = a202 = a203 = a204 = a205 = a206 = a207 = a208 = a209 = a210 = \
a211 = a212 = a213 = a214 = a215 = a216 = a217 = a218 = a219 = a220 = \
a221 = a222 = a223 = a224 = a225 = a226 = a227 = a228 = a229 = a230 = \
a231 = a232 = a233 = a234 = a235 = a236 = a237 = a238 = a239 = a240 = \
a241 = a242 = a243 = a244 = a245 = a246 = a247 = a248 = a249 = a250 = \
a251 = a252 = a253 = a254 = a255 = a256 = a257 = a258 = a259 = a260 = \
a261 = a262 = a263 = a264 = a265 = a266 = a267 = a268 = a269 = a270 = \
a271 = a272 = a273 = a274 = a275 = a276 = a277 = a278 = a279 = a280 = \
a281 = a282 = a283 = a284 = a285 = a286 = a287 = a288 = a289 = a290 = \
a291 = a292 = a293 = a294 = a295 = a296 = a297 = a298 = a299 = a300 = \
a301 = a302 = a303 = a304 = a305 = a306 = a307 = a308 = a309 = a310 = \
a311 = a312 = a313 = a314 = a315 = a316 = a317 = a318 = a319 = a320 = \
a321 = a322 = a323 = a324 = a325 = a326 = a327 = a328 = a329 = a330 = \
a331 = a332 = a333 = a334 = a335 = a336 = a337 = a338 = a339 = a340 = \
a341 = a342 = a343 = a344 = a345 = a346 = a347 = a348 = a349 = a350 = \
a351 = a352 = a353 = a354 = a355 = a356 = a357 = a358 = a359 = a360 = \
a361 = a362 = a363 = a364 = a365 = a366 = a367 = a368 = a369 = a370 = \
a371 = a372 = a373 = a374 = a375 = a376 = a377 = a378 = a379 = a380 = \
a381 = a382 = a383 = a384 = a385 = a386 = a387 = a388 = a389 = a390 = \
a391 = a392 = a393 = a394 = a395 = a396 = a397 = a398 = a399 = a400 = \
a401 = a402 = a403 = a404 = a405 = a406 = a407 = a408 = a409 = a410 = \
a411 = a412 = a413 = a414 = a415 = a416 = a417 = a418 = a419 = a420 = \
a421 = a422 = a423 = a424 = a425 = a426 = a427 = a428 = a429 = a430 = \
a431 = a432 = a433 = a434 = a435 = a436 = a437 = a438 = a439 = a440 = \
a441 = a442 = a443 = a444 = a445 = a446 = a447 = a448 = a449 = a450 = \
a451 = a452 = a453 = a454 = a455 = a456 = a457 = a458 = a459 = a460 = \
a461 = a462 = a463 = a464 = a465 = a466 = a467 = a468 = a469 = a470 = \
a471 = a472 = a473 = a474 = a475 = a476 = a477 = a478 = a479 = a480 = \
a481 = a482 = a483 = a484 = a485 = a486 = a487 = a488 = a489 = a490 = \
a491 = a492 = a493 = a494 = a495 = a496 = a497 = a498 = a499 = a500 = \
a501 = a502 = a503 = a504 = a505 = a506 = a507 = a508 = a509 = a510 = \
a511 = a512 = a513 = a514 = a515 = a516 = a517 = a518 = a519 = a520 = \
a521 = a522 = a523 = a524 = a525 = a526 = a527 = a528 = a529 = a530 = \
a531 = a532 = a533 = a534 = a535 = a536 = a537 = a538 = a539 = a540 = \
a541 = a542 = a543 = a544 = a545 = a546 = a547 = a548 = a549 = a550 = \
a551 = a552 = a553 = a554 = a555 = a556 = a557 = a558 = a559 = a560 = \
a561 = a562 = a563 = a564 = a565 = a566 = a567 = a568 = a569 = a570 = \
a571 = a572 = a573 = a574 = a575 = a576 = a577 = a578 = a579 = a580 = \
a581 = a582 = a583 = a584 = a585 = a586 = a587 = a588 = a589 = a590 = \
a591 = a592 = a593 = a594 = a595 = a596 = a597 = a598 = a599 = a600 = \
a601 = a602 = a603 = a604 = a605 = a606 = a607 = a608 = a609 = a610 = \
a611 = a612 = a613 = a614 = a615 = a616 = a617 = a618 = a619 = a620 = \
a621 = a622 = a623 = a624 = a625 = a626 = a627 = a628 = a629 = a630 = \
a631 = a632 = a633 = a634 = a635 = a636 = a637 = a638 = a639 = a640 = \
a641 = a642 = a643 = a644 = a645 = a646 = a647 = a648 = a649 = a650 = \
a651 = a652 = a653 = a654 = a655 = a656 = a657 = a658 = a659 = a660 = \
a661 = a662 = a663 = a664 = a665 = a666 = a667 = a668 = a669 = a670 = \
a671 = a672 = a673 = a674 = a675 = a676 = a677 = a678 = a679 = a680 = \
a681 = a682 = a683 = a684 = a685 = a686 = a687 = a688 = a689 = a690 = \
a691 = a692 = a693 = a694 = a695 = a696 = a697 = a698 = a699 = a700 = \
a701 = a702 = a703 = a704 = a705 = a706 = a707 = a708 = a709 = a710 = \
a711 = a712 = a713 = a714 = a715 = a716 = a717 = a718 = a719 = a720 = \
a721 = a722 = a723 = a724 = a725 = a726 = a727 = a728 = a729 = a730 = \
a731 = a732 = a733 = a734 = a735 = a736 = a737 = a738 = a739 = a740 = \
a741 = a742 = a743 = a744 = a745 = a746 = a747 = a748 = a749 = a750 = \
a751 = a752 = a753 = a754 = a755 = a756 = a757 = a758 = a759 = a760 = \
a761 = a762 = a763 = a764 = a765 = a766 = a767 = a768 = a769 = a770 = \
a771 = a772 = a773 = a774 = a775 = a776 = a777 = a778 = a779 = a780 = \
a781 = a782 = a783 = a784 = a785 = a786 = a787 = a788 = a789 = a790 = \
a791 = a792 = a793 = a794 = a795 = a796 = a797 = a798 = a799 = a800 \
= None
print(a0)
actual = self.get_suggestion(func)
self.assertNotRegex(actual, r"NameError.*a1")
def test_name_error_with_custom_exceptions(self):
def func():
blech = None
raise NameError()
actual = self.get_suggestion(func)
self.assertNotIn("blech", actual)
def func():
blech = None
raise NameError
actual = self.get_suggestion(func)
self.assertNotIn("blech", actual)
def test_unbound_local_error_does_not_match(self):
def func():
something = 3
print(somethong)
somethong = 3
actual = self.get_suggestion(func)
self.assertNotIn("something", actual)
class PurePythonSuggestionFormattingTests(
PurePythonExceptionFormattingMixin,
SuggestionFormattingTestBase,
unittest.TestCase,
):
"""
Same set of tests as above using the pure Python implementation of
traceback printing in traceback.py.
"""
@cpython_only
class CPythonSuggestionFormattingTests(
CAPIExceptionFormattingMixin,
SuggestionFormattingTestBase,
unittest.TestCase,
):
"""
Same set of tests as above but with Python's internal traceback printing.
"""
class MiscTest(unittest.TestCase):
def test_all(self):
@ -2800,6 +3221,59 @@ class MiscTest(unittest.TestCase):
expected.add(name)
self.assertCountEqual(traceback.__all__, expected)
def test_levenshtein_distance(self):
# copied from _testinternalcapi.test_edit_cost
# to also exercise the Python implementation
def CHECK(a, b, expected):
actual = traceback._levenshtein_distance(a, b, 4044)
self.assertEqual(actual, expected)
CHECK("", "", 0)
CHECK("", "a", 2)
CHECK("a", "A", 1)
CHECK("Apple", "Aple", 2)
CHECK("Banana", "B@n@n@", 6)
CHECK("Cherry", "Cherry!", 2)
CHECK("---0---", "------", 2)
CHECK("abc", "y", 6)
CHECK("aa", "bb", 4)
CHECK("aaaaa", "AAAAA", 5)
CHECK("wxyz", "wXyZ", 2)
CHECK("wxyz", "wXyZ123", 8)
CHECK("Python", "Java", 12)
CHECK("Java", "C#", 8)
CHECK("AbstractFoobarManager", "abstract_foobar_manager", 3+2*2)
CHECK("CPython", "PyPy", 10)
CHECK("CPython", "pypy", 11)
CHECK("AttributeError", "AttributeErrop", 2)
CHECK("AttributeError", "AttributeErrorTests", 10)
CHECK("ABA", "AAB", 4)
def test_levenshtein_distance_short_circuit(self):
if not LEVENSHTEIN_DATA_FILE.is_file():
self.fail(
f"{LEVENSHTEIN_DATA_FILE} is missing."
f" Run `make regen-test-levenshtein`"
)
with LEVENSHTEIN_DATA_FILE.open("r") as f:
examples = json.load(f)
for a, b, expected in examples:
res1 = traceback._levenshtein_distance(a, b, 1000)
self.assertEqual(res1, expected, msg=(a, b))
for threshold in [expected, expected + 1, expected + 2]:
# big enough thresholds shouldn't change the result
res2 = traceback._levenshtein_distance(a, b, threshold)
self.assertEqual(res2, expected, msg=(a, b, threshold))
for threshold in range(expected):
# for small thresholds, the only piece of information
# we receive is "strings not close enough".
res3 = traceback._levenshtein_distance(a, b, threshold)
self.assertGreater(res3, threshold, msg=(a, b, threshold))
if __name__ == "__main__":
unittest.main()

View File

@ -707,6 +707,11 @@ class TracebackException:
self.offset = exc_value.offset
self.end_offset = exc_value.end_offset
self.msg = exc_value.msg
elif exc_type and issubclass(exc_type, (NameError, AttributeError)) and \
getattr(exc_value, "name", None) is not None:
suggestion = _compute_suggestion_error(exc_value, exc_traceback)
if suggestion:
self._str += f". Did you mean: '{suggestion}'?"
if lookup_lines:
self._load_lines()
self.__suppress_context__ = \
@ -977,3 +982,125 @@ class TracebackException:
file = sys.stderr
for line in self.format(chain=chain):
print(line, file=file, end="")
_MAX_CANDIDATE_ITEMS = 750
_MAX_STRING_SIZE = 40
_MOVE_COST = 2
_CASE_COST = 1
def _substitution_cost(ch_a, ch_b):
if ch_a == ch_b:
return 0
if ch_a.lower() == ch_b.lower():
return _CASE_COST
return _MOVE_COST
def _compute_suggestion_error(exc_value, tb):
wrong_name = getattr(exc_value, "name", None)
if wrong_name is None or not isinstance(wrong_name, str):
return None
if isinstance(exc_value, AttributeError):
obj = exc_value.obj
try:
d = dir(obj)
except Exception:
return None
else:
assert isinstance(exc_value, NameError)
# find most recent frame
if tb is None:
return None
while tb.tb_next is not None:
tb = tb.tb_next
frame = tb.tb_frame
d = (
list(frame.f_locals)
+ list(frame.f_globals)
+ list(frame.f_globals['__builtins__'])
)
if len(d) > _MAX_CANDIDATE_ITEMS:
return None
wrong_name_len = len(wrong_name)
if wrong_name_len > _MAX_STRING_SIZE:
return None
best_distance = wrong_name_len
suggestion = None
for possible_name in d:
if possible_name == wrong_name:
# A missing attribute is "found". Don't suggest it (see GH-88821).
continue
# No more than 1/3 of the involved characters should need changed.
max_distance = (len(possible_name) + wrong_name_len + 3) * _MOVE_COST // 6
# Don't take matches we've already beaten.
max_distance = min(max_distance, best_distance - 1)
current_distance = _levenshtein_distance(wrong_name, possible_name, max_distance)
if current_distance > max_distance:
continue
if not suggestion or current_distance < best_distance:
suggestion = possible_name
best_distance = current_distance
return suggestion
def _levenshtein_distance(a, b, max_cost):
# A Python implementation of Python/suggestions.c:levenshtein_distance.
# Both strings are the same
if a == b:
return 0
# Trim away common affixes
pre = 0
while a[pre:] and b[pre:] and a[pre] == b[pre]:
pre += 1
a = a[pre:]
b = b[pre:]
post = 0
while a[:post or None] and b[:post or None] and a[post-1] == b[post-1]:
post -= 1
a = a[:post or None]
b = b[:post or None]
if not a or not b:
return _MOVE_COST * (len(a) + len(b))
if len(a) > _MAX_STRING_SIZE or len(b) > _MAX_STRING_SIZE:
return max_cost + 1
# Prefer shorter buffer
if len(b) < len(a):
a, b = b, a
# Quick fail when a match is impossible
if (len(b) - len(a)) * _MOVE_COST > max_cost:
return max_cost + 1
# Instead of producing the whole traditional len(a)-by-len(b)
# matrix, we can update just one row in place.
# Initialize the buffer row
row = list(range(_MOVE_COST, _MOVE_COST * (len(a) + 1), _MOVE_COST))
result = 0
for bindex in range(len(b)):
bchar = b[bindex]
distance = result = bindex * _MOVE_COST
minimum = sys.maxsize
for index in range(len(a)):
# 1) Previous distance in this row is cost(b[:b_index], a[:index])
substitute = distance + _substitution_cost(bchar, a[index])
# 2) cost(b[:b_index], a[:index+1]) from previous row
distance = row[index]
# 3) existing result is cost(b[:b_index+1], a[index])
insert_delete = min(result, distance) + _MOVE_COST
result = min(insert_delete, substitute)
# cost(b[:b_index+1], a[:index+1])
row[index] = result
if result < minimum:
minimum = result
if minimum > max_cost:
# Everything in this row is too big, so bail early.
return max_cost + 1
return result

View File

@ -958,6 +958,11 @@ regen-test-frozenmain: $(BUILDPYTHON)
# using Programs/freeze_test_frozenmain.py
$(RUNSHARED) ./$(BUILDPYTHON) $(srcdir)/Programs/freeze_test_frozenmain.py Programs/test_frozenmain.h
.PHONY: regen-test-levenshtein
regen-test-levenshtein:
# Regenerate Lib/test/levenshtein_examples.json
$(PYTHON_FOR_REGEN) $(srcdir)/Tools/scripts/generate_levenshtein_examples.py Lib/test/levenshtein_examples.json
.PHONY: regen-re
regen-re: $(BUILDPYTHON)
# Regenerate Lib/re/_casefix.py
@ -1223,7 +1228,7 @@ regen-limited-abi: all
regen-all: regen-opcode regen-opcode-targets regen-typeslots \
regen-token regen-ast regen-keyword regen-sre regen-frozen clinic \
regen-pegen-metaparser regen-pegen regen-test-frozenmain \
regen-global-objects
regen-test-levenshtein regen-global-objects
@echo
@echo "Note: make regen-stdlib-module-names and make regen-configure should be run manually"

View File

@ -0,0 +1,5 @@
:exc:`NameError` and :exc:`AttributeError` spelling suggestions provided
since :gh:`82711` are now also emitted by the pure Python
:mod:`traceback` module. Tests for those suggestions now exercise both
implementations to ensure they are equivalent. Patch by Carl Friedrich
Bolz-Tereick and Łukasz Langa.

View File

@ -0,0 +1,70 @@
"""Generate 10,000 unique examples for the Levenshtein short-circuit tests."""
import argparse
from functools import cache
import json
import os.path
from random import choices, randrange
# This should be in sync with Lib/traceback.py. It's not importing those values
# because this script is being executed by PYTHON_FOR_REGEN and not by the in-tree
# build of Python.
_MOVE_COST = 2
_CASE_COST = 1
def _substitution_cost(ch_a, ch_b):
if ch_a == ch_b:
return 0
if ch_a.lower() == ch_b.lower():
return _CASE_COST
return _MOVE_COST
@cache
def levenshtein(a, b):
if not a or not b:
return (len(a) + len(b)) * _MOVE_COST
option1 = levenshtein(a[:-1], b[:-1]) + _substitution_cost(a[-1], b[-1])
option2 = levenshtein(a[:-1], b) + _MOVE_COST
option3 = levenshtein(a, b[:-1]) + _MOVE_COST
return min(option1, option2, option3)
def main():
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument('output_path', metavar='FILE', type=str)
parser.add_argument('--overwrite', dest='overwrite', action='store_const',
const=True, default=False,
help='overwrite an existing test file')
args = parser.parse_args()
output_path = os.path.realpath(args.output_path)
if not args.overwrite and os.path.isfile(output_path):
print(f"{output_path} already exists, skipping regeneration.")
print(
"To force, add --overwrite to the invocation of this tool or"
" delete the existing file."
)
return
examples = set()
# Create a lot of non-empty examples, which should end up with a Gauss-like
# distribution for even costs (moves) and odd costs (case substitutions).
while len(examples) < 9990:
a = ''.join(choices("abcABC", k=randrange(1, 10)))
b = ''.join(choices("abcABC", k=randrange(1, 10)))
expected = levenshtein(a, b)
examples.add((a, b, expected))
# Create one empty case each for strings between 0 and 9 in length.
for i in range(10):
b = ''.join(choices("abcABC", k=i))
expected = levenshtein("", b)
examples.add(("", b, expected))
with open(output_path, "w") as f:
json.dump(sorted(examples), f, indent=2)
if __name__ == "__main__":
main()