Skip to content
This repository was archived by the owner on Apr 14, 2022. It is now read-only.
This repository was archived by the owner on Apr 14, 2022. It is now read-only.

PLS incorrectly reports error for self-assignment to local variable #513

Description

@erictraut

The analyzer incorrectly flags the following (admittedly strange) code with a use-before-def error/warning.

screen shot 2018-12-26 at 10 45 46 am

The problem is due to a somewhat hacky piece of code in DDG.Walk(AssignmentStatement node) that attempts to detect the case "fob = fob" and temporarily manipulate the scope before evaluating the RHS of the assignment. This hack is problematic for a number of reasons. For example, it doesn't properly handle other more complex expressions like "fob = fob + 1".

I think the preferable solution is to remove the hack but modify the logic to allow reading of symbols in outer scopes even if VisibleToChildren is false. This property should probably be renamed WritableByChildren since Python allows reading of symbols from outer scopes.

See the following documentation in section 2.1 of the official Python docs.

screen shot 2018-12-26 at 10 59 02 am

Activity

  1. changed the title [-]PLS incorrectly reports error for self-assignment to input parameters[/-] [+]PLS incorrectly reports error for self-assignment to local variable[/+] on Dec 26, 2018
  2. MikhailArkhipov commented on Dec 27, 2018

    @MikhailArkhipov

    We are not actively developing current analysis code as per #425 we are replacing DDG analysis (user files) and AST analysis (libraries) by a combination. The new analysis code base is in development, partial is here #465. It is a separate code, we just keep existing code around so we can check behavior and port tests.

    If you install ZenHub in Chrome, you will be able to better see epics and the milestone board.

  3. erictraut commented on Dec 27, 2018

    @erictraut
    Author

    I confirmed that this same problem exists in #465.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Labels

No labels
No labels

Type

No type

Projects

No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions