Converting generator expression to list comprehension in Python

[q0w]

Hi, I have a following rule:

id: join-generator
message: placeholder
severity: error
language: Python
rule:
  pattern: $GEN
  kind: generator_expression
  follows:
    kind: attribute
    has:
      kind: identifier
      pattern: join
fix: "([$GEN])"

The rule fix converts "".join(i for i in ["1"]) to "".join([(i for i in ["1"])]. (should be "".join([i for i in ["1"]])
Is it possible to get a generator expression without parentheses?

[HerringtonDarkholme]

Looks like it is impossible to do it here...
Python generator is very unique in that parentheses are shared by the generator_expression and call expression.
And it is impossible to make a contextual pattern because ($$$A) is not interpreted as a generator expression.

I think it might need string manipulation to make it work.

Reference: #315

[HerringtonDarkholme]

Reference: semgrep also has a hard time about Python comprehension semgrep/semgrep#4499

[HerringtonDarkholme]

Comby cannot get it right as well

https://comby.live/index.html#{%22source%22:%22if%20(width%20%3C=%201280%20&&%20height%20%3C=%20800)%20{\n%20%20%20%20return%201;\n}%22,%22match%22:%22if%20(:[var]%20%3C=%20:[rest])%22,%22rule%22:%22where%20true%22,%22rewrite%22:%22var%20matched:%20:[var]\nrest%20matched:%20:[rest]%22,%22language%22:%22.generic%22,%22substitution_kind%22:%22newline_separated%22,%22id%22:0}

[HerringtonDarkholme]

[q0w]

It works for sg scan, but not for sg test -> generated snapshot is wrong

[HerringtonDarkholme]

Thanks for reporting! That's why it's still an experimental feature...

[q0w]

Anyway, thanks for the feature

[HerringtonDarkholme]

Supported in 0.6.5!

[q0w]

Thanks!