ruff/crates/ruff_python_parser/resources/valid/statement/try.py
Dhruv Manilawala 13ffb5bc19
Replace LALRPOP parser with hand-written parser (#10036)
(Supersedes #9152, authored by @LaBatata101)

## Summary

This PR replaces the current parser generated from LALRPOP to a
hand-written recursive descent parser.

It also updates the grammar for [PEP
646](https://peps.python.org/pep-0646/) so that the parser outputs the
correct AST. For example, in `data[*x]`, the index expression is now a
tuple with a single starred expression instead of just a starred
expression.

Beyond the performance improvements, the parser is also error resilient
and can provide better error messages. The behavior as seen by any
downstream tools isn't changed. That is, the linter and formatter can
still assume that the parser will _stop_ at the first syntax error. This
will be updated in the following months.

For more details about the change here, refer to the PR corresponding to
the individual commits and the release blog post.

## Test Plan

Write _lots_ and _lots_ of tests for both valid and invalid syntax and
verify the output.

## Acknowledgements

- @MichaReiser for reviewing 100+ parser PRs and continuously providing
guidance throughout the project
- @LaBatata101 for initiating the transition to a hand-written parser in
#9152
- @addisoncrump for implementing the fuzzer which helped
[catch](https://github.com/astral-sh/ruff/pull/10903)
[a](https://github.com/astral-sh/ruff/pull/10910)
[lot](https://github.com/astral-sh/ruff/pull/10966)
[of](https://github.com/astral-sh/ruff/pull/10896)
[bugs](https://github.com/astral-sh/ruff/pull/10877)

---------

Co-authored-by: Victor Hugo Gomes <labatata101@linuxmail.org>
Co-authored-by: Micha Reiser <micha@reiser.io>
2024-04-18 17:57:39 +05:30

99 lines
1.2 KiB
Python

try:
...
except:
...
try:
...
except Exception1 as e:
...
except Exception2 as e:
...
try:
...
except Exception as e:
...
except:
...
finally:
...
try:
...
except:
...
else:
...
try:
...
except:
...
else:
...
finally:
...
try:
...
finally:
...
try:
...
else:
...
finally:
...
try:
...
except* GroupA as eg:
...
except* ExceptionGroup:
...
try:
raise ValueError(1)
except TypeError as e:
print(f"caught {type(e)}")
except OSError as e:
print(f"caught {type(e)}")
try:
raise ExceptionGroup("eg", [ValueError(1), TypeError(2), OSError(3), OSError(4)])
except* TypeError as e:
print(f"caught {type(e)} with nested {e.exceptions}")
except* OSError as e:
print(f"caught {type(e)} with nested {e.exceptions}")
try:
pass
except "exception":
pass
except 1:
pass
except True:
pass
except 1 + 1:
pass
except a | b:
pass
except x and y:
pass
except await x:
pass
except lambda x: x:
pass
except x if True else y:
pass
if True:
try:
pass
finally:
pass
# This `else` is not part of the `try` statement, so don't raise an error
else:
pass