Ameba 1.3.0 has been released

This release adds 3 new lint rules, enables Lint/EmptyExpression by default, and brings several bug fixes and quality-of-life improvements. Check out the release notes to see a full scope of changes.

New rules

Lint/LiteralsComparison

A rule that detects comparisons between literal values — comparisons that always produce the same result and are likely unintended.

"foo" == "foo"   # => always true
"foo" != "foo"   # => always false
"foo" === "foo"  # => always the same
"foo" == 42      # => always false

Lint/NotNil

A rule that flags usages of not_nil! calls. The not_nil! method raises when the value is nil, so it’s safer to use pattern matching or a conditional instead.

# Bad
alice = names.find { |name| name == "Alice" }.not_nil!

# Good
if alice = names.find { |name| name == "Alice" }
  # ...
end

Note: calls with an explicit argument (e.g. not_nil!("foo")) are not affected.

Lint/NotNilAfterNoBang

A rule that detects index or find calls chained with not_nil!, and autocorrects them to use the bang variant (index! / find!).

(1..3).index(1).not_nil!
(1..3).find { |i| i > 2 }.not_nil!

(1..3).index!(1)
(1..3).find! { |i| i > 2 }

The autocorrection is safe since index! and find! already raise on no match, making the subsequent not_nil! redundant.

Notable changes

Lint/EmptyExpression enabled by default

The Lint/EmptyExpression rule was previously disabled due to a false positive in Crystal’s parser (crystal#9857). That issue has since been fixed, so the rule is now enabled by default.

# Bad
foo = ()

if ()
  bar
end

Bug fixes & improvements

• Source::Corrector#remove_leading and #remove_trailing — fixed a compile error that occurred when using these methods (#289).
• Rule::Base+.parsed_doc — now populated at compile time, fixing a runtime issue where rule docs could be missing (#282).
• Performance — replaced Digest::SHA1.hexdigest with String#hash for internal hashing (#286).
• Internal refactoring — reduced usage of Object#not_nil! throughout Ameba’s own codebase, aligning with the new Lint/NotNil rule (#281).
• Cosmetic — removed trailing dots from rule descriptions for consistency (#290).