jbender/motion-spec

This cop enforces the use of either #alias or #alias_method depending on configuration. It also flags uses of alias :symbol rather than alias bareword.

Example: EnforcedStyle: prefer_alias (default)

# bad
alias_method :bar, :foo
alias :bar :foo

# good
alias bar foo

Example: EnforcedStyle: preferaliasmethod

# bad
alias :bar :foo
alias bar foo

# good
alias_method :bar, :foo

This cop enforces the use of either #alias or #alias_method depending on configuration. It also flags uses of alias :symbol rather than alias bareword.

Example: EnforcedStyle: prefer_alias (default)

# bad
alias_method :bar, :foo
alias :bar :foo

# good
alias bar foo

Example: EnforcedStyle: preferaliasmethod

# bad
alias :bar :foo
alias bar foo

# good
alias_method :bar, :foo

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?

This cop checks the indentation of the first element in an array literal where the opening bracket and the first element are on separate lines. The other elements' indentations are handled by the AlignArray cop.

By default, array literals that are arguments in a method call with parentheses, and where the opening square bracket of the array is on the same line as the opening parenthesis of the method call, shall have their first element indented one step (two spaces) more than the position inside the opening parenthesis.

Other array literals shall have their first element indented one step more than the start of the line where the opening square bracket is.

This default style is called 'specialinsideparentheses'. Alternative styles are 'consistent' and 'align_brackets'. Here are examples:

Example: EnforcedStyle: specialinsideparentheses (default)

# The `special_inside_parentheses` style enforces that the first
# element in an array literal where the opening bracket and first
# element are on seprate lines is indented one step (two spaces) more
# than the position inside the opening parenthesis.

#bad
array = [
  :value
]
and_in_a_method_call([
  :no_difference
                     ])

#good
array = [
  :value
]
but_in_a_method_call([
                       :its_like_this
                     ])

Example: EnforcedStyle: consistent

# The `consistent` style enforces that the first element in an array
# literal where the opening bracket and the first element are on
# seprate lines is indented the same as an array literal which is not
# defined inside a method call.

#bad
# consistent
array = [
  :value
]
but_in_a_method_call([
                       :its_like_this
])

#good
array = [
  :value
]
and_in_a_method_call([
  :no_difference
])

Example: EnforcedStyle: align_brackets

# The `align_brackets` style enforces that the opening and closing
# brackets are indented to the same position.

#bad
# align_brackets
and_now_for_something = [
                          :completely_different
]

#good
# align_brackets
and_now_for_something = [
                          :completely_different
                        ]

This cop enforces the use of either #alias or #alias_method depending on configuration. It also flags uses of alias :symbol rather than alias bareword.

Example: EnforcedStyle: prefer_alias (default)

# bad
alias_method :bar, :foo
alias :bar :foo

# good
alias bar foo

Example: EnforcedStyle: preferaliasmethod

# bad
alias :bar :foo
alias bar foo

# good
alias_method :bar, :foo

This cop checks the indentation of the method name part in method calls that span more than one line.

Example: EnforcedStyle: aligned

# bad
while myvariable
.b
  # do something
end

# good
while myvariable
      .b
  # do something
end

# good
Thing.a
     .b
     .c

Example: EnforcedStyle: indented

# good
while myvariable
  .b

  # do something
end

Example: EnforcedStyle: indentedrelativeto_receiver

# good
while myvariable
        .a
        .b

  # do something
end

# good
myvariable = Thing
               .a
               .b
               .c

Checks for colon (:) not followed by some kind of space. N.B. this cop does not handle spaces after a ternary operator, which are instead handled by Layout/SpaceAroundOperators.

Example:

# bad
def f(a:, b:2); {a:3}; end

# good
def f(a:, b: 2); {a: 3}; end

Use a guard clause instead of wrapping the code inside a conditional expression

Example:

# bad
def test
  if something
    work
  end
end

# good
def test
  return unless something
  work
end

# also good
def test
  work if something
end

# bad
if something
  raise 'exception'
else
  ok
end

# good
raise 'exception' if something
ok

This cop checks for rescuing StandardError. There are two supported styles implicit and explicit. This cop will not register an offense if any error other than StandardError is specified.

Example: EnforcedStyle: implicit

# `implicit` will enforce using `rescue` instead of
# `rescue StandardError`.

# bad
begin
  foo
rescue StandardError
  bar
end

# good
begin
  foo
rescue
  bar
end

# good
begin
  foo
rescue OtherError
  bar
end

# good
begin
  foo
rescue StandardError, SecurityError
  bar
end

Example: EnforcedStyle: explicit (default)

# `explicit` will enforce using `rescue StandardError`
# instead of `rescue`.

# bad
begin
  foo
rescue
  bar
end

# good
begin
  foo
rescue StandardError
  bar
end

# good
begin
  foo
rescue OtherError
  bar
end

# good
begin
  foo
rescue StandardError, SecurityError
  bar
end

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

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

This cop checks the args passed to fail and raise. For exploded style (default), it recommends passing the exception class and message to raise, rather than construct an instance of the error. It will still allow passing just a message, or the construction of an error with more than one argument.

The exploded style works identically, but with the addition that it will also suggest constructing error objects when the exception is passed multiple arguments.

Example: EnforcedStyle: exploded (default)

# bad
raise StandardError.new("message")

# good
raise StandardError, "message"
fail "message"
raise MyCustomError.new(arg1, arg2, arg3)
raise MyKwArgError.new(key1: val1, key2: val2)

Example: EnforcedStyle: compact

# bad
raise StandardError, "message"
raise RuntimeError, arg1, arg2, arg3

# good
raise StandardError.new("message")
raise MyCustomError.new(arg1, arg2, arg3)
fail "message"

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

This cop checks the args passed to fail and raise. For exploded style (default), it recommends passing the exception class and message to raise, rather than construct an instance of the error. It will still allow passing just a message, or the construction of an error with more than one argument.

The exploded style works identically, but with the addition that it will also suggest constructing error objects when the exception is passed multiple arguments.

Example: EnforcedStyle: exploded (default)

# bad
raise StandardError.new("message")

# good
raise StandardError, "message"
fail "message"
raise MyCustomError.new(arg1, arg2, arg3)
raise MyKwArgError.new(key1: val1, key2: val2)

Example: EnforcedStyle: compact

# bad
raise StandardError, "message"
raise RuntimeError, arg1, arg2, arg3

# good
raise StandardError.new("message")
raise MyCustomError.new(arg1, arg2, arg3)
fail "message"

Use a consistent style for named format string tokens.

Note: unannotated style cop only works for strings which are passed as arguments to those methods: sprintf, format, %. The reason is that unannotated format is very similar to encoded URLs or Date/Time formatting strings.

Example: EnforcedStyle: annotated (default)

# bad
format('%{greeting}', greeting: 'Hello')
format('%s', 'Hello')

# good
format('%<greeting>s', greeting: 'Hello')</greeting>

Example: EnforcedStyle: template

# bad
format('%<greeting>s', greeting: 'Hello')
format('%s', 'Hello')

# good
format('%{greeting}', greeting: 'Hello')</greeting>

Example: EnforcedStyle: unannotated

# bad
format('%<greeting>s', greeting: 'Hello')
format('%{greeting}', 'Hello')

# good
format('%s', 'Hello')</greeting>

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

Use a consistent style for named format string tokens.

Note: unannotated style cop only works for strings which are passed as arguments to those methods: sprintf, format, %. The reason is that unannotated format is very similar to encoded URLs or Date/Time formatting strings.

Example: EnforcedStyle: annotated (default)

# bad
format('%{greeting}', greeting: 'Hello')
format('%s', 'Hello')

# good
format('%<greeting>s', greeting: 'Hello')</greeting>

Example: EnforcedStyle: template

# bad
format('%<greeting>s', greeting: 'Hello')
format('%s', 'Hello')

# good
format('%{greeting}', greeting: 'Hello')</greeting>

Example: EnforcedStyle: unannotated

# bad
format('%<greeting>s', greeting: 'Hello')
format('%{greeting}', 'Hello')

# good
format('%s', 'Hello')</greeting>