[flake8-implicit-str-concat] Avoid invalid fix generated by autofix (ISC003)

[prakhar1144]

Summary

As reported in #19757:
While attempting ISC003 autofix for an expression with explicit string concatenation, with either operand being a string literal that wraps across multiple lines (in parentheses) - it resulted in generating a fix which caused runtime error.

Example:

_ = "abc" + (
    "def"
    "ghi"
)

was being auto-fixed to:

_ = "abc" (
    "def"
    "ghi"
)

which raised TypeError: 'str' object is not callable

This commit makes changes to just report diagnostic - no autofix in such cases.

Fixes #19757.

Test Plan

Added example scenarios in crates/ruff_linter/resources/test/fixtures/flake8_implicit_str_concat/ISC.py.

[prakhar1144]

As per suggestion in #19778 (comment):

I think we can probably just use this helper function to check if left and right are parenthesized and avoid the fix if either of them is

We can also still report a diagnostic in this case, we just can't autofix it. Another option would be to try to move one of the expressions into the existing parentheses from the other expression, but that might be too involved. I'd be happy with just offering a diagnostic but no fix if one of them is parenthesized to avoid causing the runtime error.

[astral-sh-bot]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[prakhar1144]

This is ready to review.