Favor modifier if
usage when having a single-line body. Another good alternative is the usage of control flow &&
/||
. Open
if filename.to_s.length > 0
- Read upRead up
- Exclude checks
Checks for if and unless statements that would fit on one line
if written as a modifier if/unless. The maximum line length is
configured in the Metrics/LineLength
cop.
Example:
# bad
if condition
do_stuff(bar)
end
unless qux.empty?
Foo.do_something
end
# good
do_stuff(bar) if condition
Foo.do_something unless qux.empty?
Favor a normal if-statement over a modifier clause in a multiline statement. Open
@mime.headers.set(
'Content-Disposition',
get_attachment_content_disposition(filepath)
) if is_attachment
- Read upRead up
- Exclude checks
Checks for uses of if/unless modifiers with multiple-lines bodies.
Example:
# bad
{
result: 'this should not happen'
} unless cond
# good
{ result: 'ok' } if cond
Use the return of the conditional for variable assignment and comparison. Open
if opts.key?(:base64_encode) && opts[:base64_encode]
@base64_encode = true
else
@base64_encode = false
end
- Exclude checks
Use !empty?
instead of length > 0
. Open
if filename.to_s.length > 0
- Read upRead up
- Exclude checks
This cop checks for numeric comparisons that can be replaced by a predicate method, such as receiver.length == 0, receiver.length > 0, receiver.length != 0, receiver.length < 1 and receiver.size == 0 that can be replaced by receiver.empty? and !receiver.empty.
Example:
# bad
[1, 2, 3].length == 0
0 == "foobar".length
array.length < 1
{a: 1, b: 2}.length != 0
string.length > 0
hash.size > 0
# good
[1, 2, 3].empty?
"foobar".empty?
array.empty?
!{a: 1, b: 2}.empty?
!string.empty?
!hash.empty?
Missing top-level class documentation comment. Open
class Filepath
- Read upRead up
- Exclude checks
This cop checks for missing top-level documentation of classes and modules. Classes with no body are exempt from the check and so are namespace modules - modules that have nothing in their bodies except classes, other modules, or constant definitions.
The documentation requirement is annulled if the class or module has a "#:nodoc:" comment next to it. Likewise, "#:nodoc: all" does the same for all its children.
Example:
# bad
class Person
# ...
end
# good
# Description/Explanation of Person class
class Person
# ...
end
Closing method call brace must be on the line after the last argument when opening brace is on a separate line from the first argument. Open
get_file_content_type(filepath, opts[:content_type]))
- Read upRead up
- Exclude checks
This cop checks that the closing brace in a method call is either on the same line as the last method argument, or a new line.
When using the symmetrical
(default) style:
If a method call's opening brace is on the same line as the first argument of the call, then the closing brace should be on the same line as the last argument of the call.
If an method call's opening brace is on the line above the first argument of the call, then the closing brace should be on the line below the last argument of the call.
When using the new_line
style:
The closing brace of a multi-line method call must be on the line after the last argument of the call.
When using the same_line
style:
The closing brace of a multi-line method call must be on the same line as the last argument of the call.
Example:
# symmetrical: bad
# new_line: good
# same_line: bad
foo(a,
b
)
# symmetrical: bad
# new_line: bad
# same_line: good
foo(
a,
b)
# symmetrical: good
# new_line: bad
# same_line: good
foo(a,
b)
# symmetrical: good
# new_line: good
# same_line: bad
foo(
a,
b
)
Always use raise
to signal exceptions. Open
fail "File \"#{filepath}\" does not exist or cannot be read"
- Read upRead up
- Exclude checks
This cop checks for uses of fail
and raise
.
Example: EnforcedStyle: only_raise (default)
# The `only_raise` style enforces the sole use of `raise`.
# bad
begin
fail
rescue Exception
# handle it
end
def watch_out
fail
rescue Exception
# handle it
end
Kernel.fail
# good
begin
raise
rescue Exception
# handle it
end
def watch_out
raise
rescue Exception
# handle it
end
Kernel.raise
Example: EnforcedStyle: only_fail
# The `only_fail` style enforces the sole use of `fail`.
# bad
begin
raise
rescue Exception
# handle it
end
def watch_out
raise
rescue Exception
# handle it
end
Kernel.raise
# good
begin
fail
rescue Exception
# handle it
end
def watch_out
fail
rescue Exception
# handle it
end
Kernel.fail
Example: EnforcedStyle: semantic
# The `semantic` style enforces the use of `fail` to signal an
# exception, then will use `raise` to trigger an offense after
# it has been rescued.
# bad
begin
raise
rescue Exception
# handle it
end
def watch_out
# Error thrown
rescue Exception
fail
end
Kernel.fail
Kernel.raise
# good
begin
fail
rescue Exception
# handle it
end
def watch_out
fail
rescue Exception
raise 'Preferably with descriptive message'
end
explicit_receiver.fail
explicit_receiver.raise