LowFile-scopePython Plug & play

Use `is` When Comparing with `None`

Identify occurrences where == None or != None is used. Using is None and is not None is more reliable because it checks identity instead of equality, preventing potential issues with overloaded __eq__ methods.

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Why this matters

Using == to check for None can fail if an object overrides equality (__eq__). The correct way to check for None is with is, which is more reliable.

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

if value == None:

Prefer

if value is None:

Related rules

From the same buckets as this rule.

Critical
Avoid equality operators in loop termination conditions
Check if loops use equality operators (== or !=) in termination conditions. These can lead to infinite loops if the condition is never met exactly. Instead, use relational operators like < or > for safer loop termination.
error-handlingreadability-refactor
Critical
Avoid Returning Null in Non-Async Task Methods
Returning null from a Task or Task<T> method causes a NullReferenceException if awaited. Use Task.CompletedTask or Task.FromResult<T>(null) instead.
error-handlingreadability-refactor+1
Critical
Avoid Using Boolean Expressions in `except` Statements
Detect `except` clauses that use `or` or `and` to catch multiple exceptions. This does not work as intended. Recommend using a tuple of exceptions instead.
error-handlingstack-python

Why this matters

Bad vs. good

Related rules

Avoid equality operators in loop termination conditions

Avoid Returning Null in Non-Async Task Methods

Avoid Using Boolean Expressions in `except` Statements

Why this matters

Bad vs. good

Related rules

Avoid equality operators in loop termination conditions

Avoid Returning Null in Non-Async Task Methods

Avoid Using Boolean Expressions in `except` Statements