Add conditions to rules to precisely target them

Jul 28, 2022

Last time we introduced custom rules into Sourcery.

This time they’re becoming even more powerful as you can filter pattern matches with a condition.

Let’s say we want to stop global variables being declared. First let’s write down what a global variable is:

1. It’s declared at the top level of the module
2. It’s not a constant using uppercase like DAYS_IN_WEEK = 7
3. Let’s allow private globals starting with _

Here’s a rule to identify global variables:

rules:
    - id: no-global-variables
      pattern: ${var} = ${value}
      condition: |
          var.in_module_scope()
            and not var.is_upper_case()
            and not var.starts_with("_")
      description: Don't declare `${var}` as a global variable

Check out the conditions reference to see what conditions are available.

Added

• Custom rules can contain a condition field that means the rule only matches when the condition is satisfied
• CLI: display a progress bar showing how many files have been reviewed
• Docs: Flag Dependencies to a Library with Sourcery custom rules
• Docs: Establish Rules for Dependencies Between Your Packages with Sourcery custom rules
• use-file-iterator refactoring

Changed

• reintroduce-else will now trigger more often
• Refactorings list-literal and dict-literal will now trigger in every instance of list() and dict(), instead of only in assignments
• CLI: display rule descriptions and explanations as Markdown
• CLI docs: present the review command instead of refactor

Fixed

• dict-assign-update-to-union doesn’t trigger for global variables
• Files using tab indenting will be always be refactored with tabs
• Identical clone detection will now only trigger for functions if they have the same name
• Recover from PermissionErrors when rotating log files
• Sourcery now run refactorings on functions containing nested functions