Use match?
instead of =~
when MatchData
is not used. Open
hostname = nil if hostname =~ /.*localhost.*/
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- Exclude checks
In Ruby 2.4, String#match?
, Regexp#match?
and Symbol#match?
have been added. The methods are faster than match
.
Because the methods avoid creating a MatchData
object or saving
backref.
So, when MatchData
is not used, use match?
instead of match
.
Example:
# bad
def foo
if x =~ /re/
do_something
end
end
# bad
def foo
if x.match(/re/)
do_something
end
end
# bad
def foo
if /re/ === x
do_something
end
end
# good
def foo
if x.match?(/re/)
do_something
end
end
# good
def foo
if x =~ /re/
do_something(Regexp.last_match)
end
end
# good
def foo
if x.match(/re/)
do_something($~)
end
end
# good
def foo
if /re/ === x
do_something($~)
end
end
Use match?
instead of =~
when MatchData
is not used. Open
if ipaddr =~ Regexp.union(Resolv::IPv4::Regex, Resolv::IPv6::Regex).freeze
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- Create a ticketCreate a ticket
- Exclude checks
In Ruby 2.4, String#match?
, Regexp#match?
and Symbol#match?
have been added. The methods are faster than match
.
Because the methods avoid creating a MatchData
object or saving
backref.
So, when MatchData
is not used, use match?
instead of match
.
Example:
# bad
def foo
if x =~ /re/
do_something
end
end
# bad
def foo
if x.match(/re/)
do_something
end
end
# bad
def foo
if /re/ === x
do_something
end
end
# good
def foo
if x.match?(/re/)
do_something
end
end
# good
def foo
if x =~ /re/
do_something(Regexp.last_match)
end
end
# good
def foo
if x.match(/re/)
do_something($~)
end
end
# good
def foo
if /re/ === x
do_something($~)
end
end
Unused method argument - args
. If it's necessary, use _
or _args
as an argument name to indicate that it won't be used. You can also write as start(*)
if you want the method to accept any arguments but don't care about them. Open
def self.start(*args)
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This cop checks for unused method arguments.
Example:
# bad
def some_method(used, unused, _unused_but_allowed)
puts used
end
# good
def some_method(used, _unused, _unused_but_allowed)
puts used
end
Example: AllowUnusedKeywordArguments: false (default)
# bad
def do_something(used, unused: 42)
used
end
Example: AllowUnusedKeywordArguments: true
# good
def do_something(used, unused: 42)
used
end
Example: IgnoreEmptyMethods: true (default)
# good
def do_something(unused)
end
Example: IgnoreEmptyMethods: false
# bad
def do_something(unused)
end
Example: IgnoreNotImplementedMethods: true (default)
# good
def do_something(unused)
raise NotImplementedError
end
def do_something_else(unused)
fail "TODO"
end
Example: IgnoreNotImplementedMethods: false
# bad
def do_something(unused)
raise NotImplementedError
end
def do_something_else(unused)
fail "TODO"
end
Use ==
if you meant to do a comparison or wrap the expression in parentheses to indicate you meant to assign in a condition. Open
if pid = MiqServer.running?
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This cop checks for assignments in the conditions of if/while/until.
AllowSafeAssignment
option for safe assignment.
By safe assignment we mean putting parentheses around
an assignment to indicate "I know I'm using an assignment
as a condition. It's not a mistake."
Example:
# bad
if some_var = true
do_something
end
# good
if some_var == true
do_something
end
Example: AllowSafeAssignment: true (default)
# good
if (some_var = true)
do_something
end
Example: AllowSafeAssignment: false
# bad
if (some_var = true)
do_something
end