LowFile-scopeRuby Plug & play

Provide Meaningful Default Values for Hash Keys

Check for hash key lookups without default values. If a missing key is accessed, suggest using `fetch` with a default value.

Why this matters

Using meaningful default values prevents errors caused by uninitialized keys, improving code robustness and reducing unexpected `nil` values.

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

Avoid

options = {}
puts options[:timeout] || 5

Prefer

options = { timeout: 5 }
puts options.fetch(:timeout)

Bad

options = {}
puts options[:timeout] || 5

Good

options = { timeout: 5 }
puts options.fetch(:timeout)

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