# mlflow
pip install git+https://github.com/mlflow/mlflow.git@refs/pull/19110/merge
# mlflow-skinny
pip install git+https://github.com/mlflow/mlflow.git@refs/pull/19110/merge#subdirectory=libs/skinny

%sh curl -LsSf https://raw.githubusercontent.com/mlflow/mlflow/HEAD/dev/install-skinny.sh | sh -s pull/19110/merge

What changes are proposed in this pull request?

Implements a new clint linting rule UseWalrusOperator (MLF0046) that detects patterns where a variable is assigned and immediately tested for truthiness in the following if statement, suggesting the use of Python's walrus operator (:=) instead.

Pattern detected:

# Before (flagged)
result = func()
if result:
    use(result)

# After (suggested)
if result := func():
    use(result)

Also supports if/elif/else - flags when the variable is only used in the if body:

# Flagged (var not used in else)
if result := func():
    use(result)
else:
    do_other()

Implementation:

• use_walrus_operator.py: Rule class with AST-based pattern detection
  • Skips comparisons, tuple unpacking, multi-line assignments
  • Skips if variable is used in elif/else branches or after the if statement
  • Respects 100-char line limit
  • Only checks inside functions (not module-level) for performance
• linter.py: Added _check_stmts_for_walrus() method, integrated into visit_FunctionDef, visit_AsyncFunctionDef
• rules/__init__.py: Registered new rule
• Applied walrus operator pattern to 67 locations across the codebase

How is this PR tested?

• Existing unit/integration tests
• New unit/integration tests

25 test cases covering positive matches and edge cases (elif/else with/without var usage, variable reuse, line length, etc.)

Does this PR require documentation update?

• No. You can skip the rest of this section.

Release Notes

Is this a user-facing change?

• No. You can skip the rest of this section.

How should the PR be classified in the release notes? Choose one:

• rn/none - No description will be included. The PR will be mentioned only by the PR number in the "Small Bugfixes and Documentation Updates" section

Should this PR be included in the next patch release?

• Yes (this PR will be cherry-picked and included in the next patch release)
• No (this PR will be included in the next minor release)