CriticalFile-scopeC# Plug & play

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.

Why this matters

Returning null from a Task or Task<T> method causes a NullReferenceException if awaited. Use Task.CompletedTask or Task.FromResult<T>(null) instead.

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

Avoid

public Task DoFooAsync()
{
    return null;               // Noncompliant: Causes a NullReferenceException if awaited.
}

Prefer

public Task DoFooAsync()
{
    return Task.CompletedTask; // Compliant: Method can be awaited.
}

Bad

public Task DoFooAsync()
{
    return null;               // Noncompliant: Causes a NullReferenceException if awaited.
}

Good

public Task DoFooAsync()
{
    return Task.CompletedTask; // Compliant: Method can be awaited.
}

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 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
Critical
Don’t Create Exceptions Without Raising Them
Identify instances where an exception object is created but never raised. This is likely an oversight and should either be removed or properly raised.
error-handlingstack-python