Cyclomatic complexity for load is too high. [7/6] Open
def load
if @path and File.exist?(@path)
file_contents = IO.read(@path)
file_contents = ERB.new(file_contents).result if evaluate_erb
result = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(file_contents) : YAML.load(file_contents)
- Read upRead up
- Exclude checks
This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.
An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.
Method load
has a Cognitive Complexity of 12 (exceeds 5 allowed). Consider refactoring. Open
def load
if @path and File.exist?(@path)
file_contents = IO.read(@path)
file_contents = ERB.new(file_contents).result if evaluate_erb
result = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(file_contents) : YAML.load(file_contents)
- Read upRead up
Cognitive Complexity
Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.
A method's cognitive complexity is based on a few simple rules:
- Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
- Code is considered more complex for each "break in the linear flow of the code"
- Code is considered more complex when "flow breaking structures are nested"
Further reading
Config::Sources::YAMLSource#load has approx 7 statements Open
def load
- Read upRead up
- Exclude checks
A method with Too Many Statements
is any method that has a large number of lines.
Too Many Statements
warns about any method that has more than 5 statements. Reek's smell detector for Too Many Statements
counts +1 for every simple statement in a method and +1 for every statement within a control structure (if
, else
, case
, when
, for
, while
, until
, begin
, rescue
) but it doesn't count the control structure itself.
So the following method would score +6 in Reek's statement-counting algorithm:
def parse(arg, argv, &error)
if !(val = arg) and (argv.empty? or /\A-/ =~ (val = argv[0]))
return nil, block, nil # +1
end
opt = (val = parse_arg(val, &error))[1] # +2
val = conv_arg(*val) # +3
if opt and !arg
argv.shift # +4
else
val[0] = nil # +5
end
val # +6
end
(You might argue that the two assigments within the first @if@ should count as statements, and that perhaps the nested assignment should count as +2.)
Config::Sources::YAMLSource has no descriptive comment Open
class YAMLSource
- Read upRead up
- Exclude checks
Classes and modules are the units of reuse and release. It is therefore considered good practice to annotate every class and module with a brief comment outlining its responsibilities.
Example
Given
class Dummy
# Do things...
end
Reek would emit the following warning:
test.rb -- 1 warning:
[1]:Dummy has no descriptive comment (IrresponsibleModule)
Fixing this is simple - just an explaining comment:
# The Dummy class is responsible for ...
class Dummy
# Do things...
end
Config::Sources::YAMLSource#load manually dispatches method call Open
result = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(file_contents) : YAML.load(file_contents)
- Read upRead up
- Exclude checks
Reek reports a Manual Dispatch smell if it finds source code that manually checks whether an object responds to a method before that method is called. Manual dispatch is a type of Simulated Polymorphism which leads to code that is harder to reason about, debug, and refactor.
Example
class MyManualDispatcher
attr_reader :foo
def initialize(foo)
@foo = foo
end
def call
foo.bar if foo.respond_to?(:bar)
end
end
Reek would emit the following warning:
test.rb -- 1 warning:
[9]: MyManualDispatcher manually dispatches method call (ManualDispatch)
Config::Sources::YAMLSource#path is a writable attribute Open
attr_accessor :path
- Read upRead up
- Exclude checks
A class that publishes a setter for an instance variable invites client classes to become too intimate with its inner workings, and in particular with its representation of state.
The same holds to a lesser extent for getters, but Reek doesn't flag those.
Example
Given:
class Klass
attr_accessor :dummy
end
Reek would emit the following warning:
reek test.rb
test.rb -- 1 warning:
[2]:Klass declares the writable attribute dummy (Attribute)
Config::Sources::YAMLSource#load has the variable name 'e' Open
rescue Psych::SyntaxError => e
- Read upRead up
- Exclude checks
An Uncommunicative Variable Name
is a variable name that doesn't communicate its intent well enough.
Poor names make it hard for the reader to build a mental picture of what's going on in the code. They can also be mis-interpreted; and they hurt the flow of reading, because the reader must slow down to interpret the names.
Missing top-level class documentation comment. Open
class YAMLSource
- 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
Prefer using YAML.safe_load
over YAML.load
. Open
result = YAML.respond_to?(:unsafe_load) ? YAML.unsafe_load(file_contents) : YAML.load(file_contents)
- Read upRead up
- Exclude checks
This cop checks for the use of YAML class methods which have potential security issues leading to remote code execution when loading from an untrusted source.
Example:
# bad
YAML.load("--- foo")
# good
YAML.safe_load("--- foo")
YAML.dump("foo")
Avoid the use of double negation (!!
). Open
@evaluate_erb = !!evaluate_erb
- Read upRead up
- Exclude checks
This cop checks for uses of double negation (!!) to convert something to a boolean value. As this is both cryptic and usually redundant, it should be avoided.
Example:
# bad
!!something
# good
!something.nil?
Please, note that when something is a boolean value !!something and !something.nil? are not the same thing. As you're unlikely to write code that can accept values of any type this is rarely a problem in practice.
Prefer single-quoted strings when you don't need string interpolation or special symbols. Open
"Please note that YAML must be consistently indented using spaces. Tabs are not allowed. " \
- Read upRead up
- Exclude checks
Checks if uses of quotes match the configured preference.
Example: EnforcedStyle: single_quotes (default)
# bad
"No special symbols"
"No string interpolation"
"Just text"
# good
'No special symbols'
'No string interpolation'
'Just text'
"Wait! What's #{this}!"
Example: EnforcedStyle: double_quotes
# bad
'Just some text'
'No special chars or interpolation'
# good
"Just some text"
"No special chars or interpolation"
"Every string in #{project} uses double_quotes"
Use &&
instead of and
. Open
if @path and File.exist?(@path)
- Read upRead up
- Exclude checks
This cop checks for uses of and
and or
, and suggests using &&
and
|| instead
. It can be configured to check only in conditions, or in
all contexts.
Example: EnforcedStyle: always (default)
# bad
foo.save and return
# bad
if foo and bar
end
# good
foo.save && return
# good
if foo && bar
end
Example: EnforcedStyle: conditionals
# bad
if foo and bar
end
# good
foo.save && return
# good
foo.save and return
# good
if foo && bar
end
Extra empty line detected before the rescue
. Open
rescue Psych::SyntaxError => e
- Read upRead up
- Exclude checks
This cops checks if empty lines exist around the bodies of begin
sections. This cop doesn't check empty lines at begin
body
beginning/end and around method definition body.
Style/EmptyLinesAroundBeginBody
or Style/EmptyLinesAroundMethodBody
can be used for this purpose.
Example:
# good
begin
do_something
rescue
do_something2
else
do_something3
ensure
do_something4
end
# good
def foo
do_something
rescue
do_something2
end
# bad
begin
do_something
rescue
do_something2
else
do_something3
ensure
do_something4
end
# bad
def foo
do_something
rescue
do_something2
end