`end_offset` is ignored in subclasses of SyntaxError (3.12-only)

[stbech]

Bug report

Bug description:

When I tried to implement a subclass of SyntaxError, the exception details ignored the end_offset-variable and just showed one caret at the position of offset.

raise SyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    a = sin(3)
        ^^^^
SyntaxError: Error message

class CustomSyntaxError(SyntaxError):
    pass
raise CustomSyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 1
    a = sin(3)
        ^
CustomSyntaxError: Error message

CPython versions tested on:

3.11, 3.12

Operating systems tested on:

Windows

Linked PRs

• [3.12] gh-111609: end_offset is ignored in subclasses of SyntaxError #127554
• gh-111609: Test end_offset in SyntaxError subclass #127830
• [3.13] gh-111609: Test end_offset in SyntaxError subclass (GH-127830) #130407

[sobolevn]

It works correctly for me on 3.13a1:

>>> class CustomSyntaxError(SyntaxError):
...     pass
... 
>>> raise CustomSyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    raise CustomSyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))
  File "<string>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message

[harshitrathor3]

Also worked correctly for me on 3.10.10

raise SyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    raise SyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))
  File "<string>", line 1
    a = sin(3)
        ^^^^
SyntaxError: Error message


class CustomSyntaxError(SyntaxError):
    pass
raise CustomSyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))
Traceback (most recent call last):
  File "<pyshell#4>", line 1, in <module>
    raise CustomSyntaxError("Error message", (None, 1, 5, 'a = sin(3)', 1, 9))
  File "<string>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message

[stbech]

For me (Python 3.11.6 on Windows 10) the console does not print the carets in the original error message, only when using the traceback package:

Python 3.11.6 (tags/v3.11.6:8b6ee5b, Oct  2 2023, 14:57:12) [MSC v.1935 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import traceback
>>> class CustomSyntaxError(SyntaxError):
...     pass
...
>>> try:
...     raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
... except Exception as e:
...     traceback.print_exc()
...     print('-'*20)
...     raise e
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
  File "<stdin>", line 2, in <module>
  File "<py>", line 1
    a = sin(3)
        ^
CustomSyntaxError: Error message
>>> raise SyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<py>", line 1
    a = sin(3)
        ^^^^
SyntaxError: Error message

See also this gist for the behavior in a Ipython console or Jupyter Notebook. There neither SyntaxError nor its subclass showed the desired result.
Maybe it has something to do with the error handling in the console, e.g. the console in PyCharm Community Edition works fine for me.

[zedzhen]

Python 3.11.1, 3.12.2 (Windows 10)
IDLE

import sys
import traceback
class CustomSyntaxError(SyntaxError):
    pass

try:
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
except Exception as e:
    traceback.print_exc()
    print('-' * 20, file=sys.stderr)
    raise e from None

Traceback (most recent call last):
  File "<pyshell#4>", line 2, in <module>
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "<pyshell#4>", line 6, in <module>
    raise e from None
  File "<pyshell#4>", line 2, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message

========= RESTART: D:\path\test.py =========
Traceback (most recent call last):
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "D:\path\test.py", line 14, in <module>
    raise e from None
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message

cmd

C:\path\Python312>python
Python 3.12.2 (tags/v3.12.2:6abddd9, Feb  6 2024, 21:26:36) [MSC v.1937 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
random, math imported
>>> import sys
>>> import traceback
>>>
>>>
>>> class CustomSyntaxError(SyntaxError):
...     pass
...
>>>
>>> try:
...     raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
... except Exception as e:
...     traceback.print_exc()
...     print('-' * 20, file=sys.stderr)
...     raise e from None
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
  File "<stdin>", line 2, in <module>
  File "<py>", line 1
    a = sin(3)
        ^
CustomSyntaxError: Error message
>>> ^Z


C:\path\Python312>python D:\path\test.py
Traceback (most recent call last):
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "D:\path\test.py", line 14, in <module>
    raise e from None
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^
CustomSyntaxError: Error message

PyCharm 2023.3.5 (Professional Edition)

Traceback (most recent call last):
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "D:\path\test.py", line 14, in <module>
    raise e from None
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^
CustomSyntaxError: Error message

test.py

import sys
import traceback


class CustomSyntaxError(SyntaxError):
    pass


try:
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
except Exception as e:
    traceback.print_exc()
    print('-' * 20, file=sys.stderr)
    raise e from None

[zedzhen]

Python 3.13.0a5 (windows 10) correct print

C:\path\Python313>python
Python 3.13.0a5 (tags/v3.13.0a5:076d169, Mar 12 2024, 21:29:03) [MSC v.1938 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
random, math imported
>>> import sys
>>> import traceback
>>>
>>>
>>> class CustomSyntaxError(SyntaxError):
...     pass
...
>>>
>>> try:
...     raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
... except Exception as e:
...     traceback.print_exc()
...     print('-' * 20, file=sys.stderr)
...     raise e from None
...
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "<stdin>", line 6, in <module>
    raise e from None
  File "<stdin>", line 2, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
>>> ^Z


C:\path\Python313>python D:\path\test.py
Traceback (most recent call last):
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message
--------------------
Traceback (most recent call last):
  File "D:\path\test.py", line 14, in <module>
    raise e from None
  File "D:\path\test.py", line 10, in <module>
    raise CustomSyntaxError("Error message", ('<py>', 1, 5, 'a = sin(3)', 1, 9))
  File "<py>", line 1
    a = sin(3)
        ^^^^
CustomSyntaxError: Error message

[nineteendo]

Can confirm on 3.12.4:

Python 3.12.4 (main, Jun  6 2024, 18:26:44) [Clang 15.0.0 (clang-1500.1.0.2.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from jsonyx import loads
>>> loads("NaN")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/wannes/Library/CloudStorage/OneDrive-Personal/Personal/GitHub/pyvz2/alpha/src/jsonyx/__init__.py", line 248, in loads
    return JSONDecoder(allow=allow).loads(s, filename=filename)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/wannes/Library/CloudStorage/OneDrive-Personal/Personal/GitHub/pyvz2/alpha/src/jsonyx/__init__.py", line 123, in loads
    return self._scanner(filename, s)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 1
    NaN
    ^
jsonyx._decoder.JSONSyntaxError: NaN is not allowed

It works correctly on 3.13.0b4:

Python 3.13.0b4 (v3.13.0b4:567c38b4eb, Jul 18 2024, 07:28:29) [Clang 15.0.0 (clang-1500.3.9.4)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from jsonyx import loads
>>> loads("NaN")
Traceback (most recent call last):
  File "<python-input-1>", line 1, in <module>
    loads("NaN")
    ~~~~~^^^^^^^
  File "/Users/wannes/Library/CloudStorage/OneDrive-Personal/Personal/GitHub/pyvz2/alpha/src/jsonyx/__init__.py", line 248, in loads
    return JSONDecoder(allow=allow).loads(s, filename=filename)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/wannes/Library/CloudStorage/OneDrive-Personal/Personal/GitHub/pyvz2/alpha/src/jsonyx/__init__.py", line 123, in loads
    return self._scanner(filename, s)
           ~~~~~~~~~~~~~^^^^^^^^^^^^^
  File "/Users/wannes/Library/CloudStorage/OneDrive-Personal/Personal/GitHub/pyvz2/alpha/src/jsonyx/_decoder.py", line 398, in scanner
    raise exc.with_traceback(None) from None
  File "<string>", line 1
    NaN
    ^^^
jsonyx._decoder.JSONSyntaxError: NaN is not allowed

[picnixz]

The bug is affecting 3.12.6 (haven't tested on 3.12.7) so I'll mark it as 3.12-only.

[nineteendo]

Could you do a bisect?