Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

gh-103895: Improve how invalid Exception.__notes__ are displayed #103897

Merged
merged 2 commits into from
May 1, 2023

Conversation

pR0Ps
Copy link
Contributor

@pR0Ps pR0Ps commented Apr 26, 2023

  • Ensure that when displayed a note fails, the failure message includes a trailing newline.
  • Improve isinstance(__notes__, Sequence) check to exclude strings and bytes to avoid exploding them into individual characters.

Potential code reviewer based on the experts index and git blame (d4c4a76): @iritkatriel

 - Ensure that when displayed a note fails, the failure message includes
   a trailing newline.
 - Improve `isinstance(__notes__, Sequence)` check to exclude strings
   and bytes to avoid exploding them into individual characters.
@iritkatriel iritkatriel added the interpreter-core (Objects, Python, Grammar, and Parser dirs) label Apr 27, 2023
@iritkatriel
Copy link
Member

@ambv any thoughts on backporting this to 3.11? It's improving the traceback display for some "invalid" values of __notes__. I don't think this is a backwards compatibility issue (people shouldn't be parsing tracebacks, right?)

@iritkatriel iritkatriel merged commit 487f55d into python:main May 1, 2023
carljm added a commit to carljm/cpython that referenced this pull request May 1, 2023
* main: (26 commits)
  pythongh-104028: Reduce object creation while calling callback function from gc (pythongh-104030)
  pythongh-104036: Fix direct invocation of test_typing (python#104037)
  pythongh-102213: Optimize the performance of `__getattr__` (pythonGH-103761)
  pythongh-103895: Improve how invalid `Exception.__notes__` are displayed (python#103897)
  Adjust expression from `==` to `!=` in alignment with the meaning of the paragraph. (pythonGH-104021)
  pythongh-88496: Fix IDLE test hang on macOS (python#104025)
  Improve int test coverage (python#104024)
  pythongh-88773: Added teleport method to Turtle library (python#103974)
  pythongh-104015: Fix direct invocation of `test_dataclasses` (python#104017)
  pythongh-104012: Ensure test_calendar.CalendarTestCase.test_deprecation_warning consistently passes (python#104014)
  pythongh-103977: compile re expressions in platform.py only if required (python#103981)
  pythongh-98003: Inline call frames for CALL_FUNCTION_EX (pythonGH-98004)
  Replace Netlify with Read the Docs build previews (python#103843)
  Update name in acknowledgements and add mailmap (python#103696)
  pythongh-82054: allow test runner to split test_asyncio to execute in parallel by sharding. (python#103927)
  Remove non-existing tools from Sundry skiplist (python#103991)
  pythongh-103793: Defer formatting task name (python#103767)
  pythongh-87092: change assembler to use instruction sequence instead of CFG (python#103933)
  pythongh-103636: issue warning for deprecated calendar constants (python#103833)
  Various small fixes to dis docs (python#103923)
  ...
carljm added a commit to carljm/cpython that referenced this pull request May 1, 2023
* main: (463 commits)
  pythongh-104057: Fix direct invocation of test_super (python#104064)
  pythongh-87092: Expose assembler to unit tests (python#103988)
  pythongh-97696: asyncio eager tasks factory (python#102853)
  pythongh-84436: Immortalize in _PyStructSequence_InitBuiltinWithFlags() (pythongh-104054)
  pythongh-104057: Fix direct invocation of test_module (pythonGH-104059)
  pythongh-100458: Clarify Enum.__format__() change of mixed-in types in the whatsnew/3.11.rst (pythonGH-100387)
  pythongh-104018: disallow "z" format specifier in %-format of byte strings (pythonGH-104033)
  pythongh-104016: Fixed off by 1 error in f string tokenizer (python#104047)
  pythonGH-103629: Update Unpack's repr in compliance with PEP 692 (python#104048)
  pythongh-102799: replace sys.exc_info by sys.exception in inspect and traceback modules (python#104032)
  Fix typo in "expected" word in few source files (python#104034)
  pythongh-103824: fix use-after-free error in Parser/tokenizer.c (python#103993)
  pythongh-104035: Do not ignore user-defined `__{get,set}state__` in slotted frozen dataclasses (python#104041)
  pythongh-104028: Reduce object creation while calling callback function from gc (pythongh-104030)
  pythongh-104036: Fix direct invocation of test_typing (python#104037)
  pythongh-102213: Optimize the performance of `__getattr__` (pythonGH-103761)
  pythongh-103895: Improve how invalid `Exception.__notes__` are displayed (python#103897)
  Adjust expression from `==` to `!=` in alignment with the meaning of the paragraph. (pythonGH-104021)
  pythongh-88496: Fix IDLE test hang on macOS (python#104025)
  Improve int test coverage (python#104024)
  ...
Carreau added a commit to ipython/ipython that referenced this pull request Jun 2, 2023
[PEP 678](https://peps.python.org/pep-0678/) introduced the ability to
add notes to exception objects. This has been [released in Python
3.11](https://docs.python.org/3/library/exceptions.html#BaseException.add_note)
and is currently not implemented in IPython. These changes are fully
compatible with older Python versions that don't include PEP 678.

Here's a sample test that shows the consistency in Python's stdlib
traceback module (test 1) and the difference between Python and
IPython's runtimes (test 2):
```python
import traceback

print('--- test 1 ---')
try:
    raise Exception('Testing notes')
except Exception as e:
    e.add_note('Does this work?')
    e.add_note('Yes!')
    traceback.print_exc()

print('\n--- test 2 ---')
try:
    raise Exception('Testing notes')
except Exception as e:
    e.add_note('Does this work?')
    e.add_note('No!')
    raise
```

When executed with Python 3.11, both notes are displayed in both
tracebacks:
```
$ python test.py 
--- test 1 ---
Traceback (most recent call last):
  File "/app/test.py", line 5, in <module>
    raise Exception('Testing notes')
Exception: Testing notes
Does this work?
Yes!

--- test 2 ---
Traceback (most recent call last):
  File "/app/test.py", line 13, in <module>
    raise Exception('Testing notes')
Exception: Testing notes
Does this work?
No!
```

In IPython's VerboseTB does not yet handle exception notes:
```
$ ipython test.py 
--- test 1 ---
Traceback (most recent call last):
  File "/app/test.py", line 5, in <module>
    raise Exception('Testing notes')
Exception: Testing notes
Does this work?
Yes!

--- test 2 ---
---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
File /app/test.py:13
     11 print('\n--- test 2 ---')
     12 try:
---> 13     raise Exception('Testing notes')
     14 except Exception as e:
     15     e.add_note('Does this work?')

Exception: Testing notes
```

The changes I am suggesting are inspired from implementation of
[Lib/traceback.py](https://github.com/python/cpython/blob/main/Lib/traceback.py)
(search for `__notes__`) and improvements for dealing with edge cases
more nicely in
[cpython#103897](python/cpython#103897).

Although notes are meant to be strings only, I kept some inspiration
from the existing exception handling to ensure that the notes are
uncolored and bytes decoded, if there are any. I am definitely open to
using a different color if deemed better. For context, `bpython` keeps
the notes uncolored, and [Python's
tutorial](https://docs.python.org/3/tutorial/errors.html#enriching-exceptions-with-notes)
puts them in light gray, like the line numbers.

Here's how the test 2 looks like after these changes:

![image](https://user-images.githubusercontent.com/16963011/234723689-6bbfe0ff-94d4-4a90-9da6-acfe1c8e5edf.png)

## 🐍 🤹‍♂️
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
interpreter-core (Objects, Python, Grammar, and Parser dirs)
Projects
None yet
Development

Successfully merging this pull request may close these issues.

3 participants