Cinch::Plugins::DevTools#variance_of refers to 'stats' more than self (maybe move it to another class?) Open
sum = stats.values.map do |value|
(value - mean) ** 2
end.reduce(0, :+)
sum / (stats.size - 1)
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Feature Envy occurs when a code fragment references another object more often than it references itself, or when several clients do the same series of manipulations on a particular type of object.
Feature Envy reduces the code's ability to communicate intent: code that "belongs" on one class but which is located in another can be hard to find, and may upset the "System of Names" in the host class.
Feature Envy also affects the design's flexibility: A code fragment that is in the wrong class creates couplings that may not be natural within the application's domain, and creates a loss of cohesion in the unwilling host class.
Feature Envy often arises because it must manipulate other objects (usually its arguments) to get them into a useful form, and one force preventing them (the arguments) doing this themselves is that the common knowledge lives outside the arguments, or the arguments are of too basic a type to justify extending that type. Therefore there must be something which 'knows' about the contents or purposes of the arguments. That thing would have to be more than just a basic type, because the basic types are either containers which don't know about their contents, or they are single objects which can't capture their relationship with their fellows of the same type. So, this thing with the extra knowledge should be reified into a class, and the utility method will most likely belong there.
Example
Running Reek on:
class Warehouse
def sale_price(item)
(item.price - item.rebate) * @vat
end
end
would report:
Warehouse#total_price refers to item more than self (FeatureEnvy)
since this:
(item.price - item.rebate)
belongs to the Item class, not the Warehouse.
Cinch::Plugins::DevTools#highlight_value refers to 'value' more than self (maybe move it to another class?) Open
if value > average + 2 * standard_deviation
Format(:red, value.to_s)
elsif value > average + standard_deviation
Format(:orange, value.to_s)
elsif value > average + standard_deviation / 2
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- Exclude checks
Feature Envy occurs when a code fragment references another object more often than it references itself, or when several clients do the same series of manipulations on a particular type of object.
Feature Envy reduces the code's ability to communicate intent: code that "belongs" on one class but which is located in another can be hard to find, and may upset the "System of Names" in the host class.
Feature Envy also affects the design's flexibility: A code fragment that is in the wrong class creates couplings that may not be natural within the application's domain, and creates a loss of cohesion in the unwilling host class.
Feature Envy often arises because it must manipulate other objects (usually its arguments) to get them into a useful form, and one force preventing them (the arguments) doing this themselves is that the common knowledge lives outside the arguments, or the arguments are of too basic a type to justify extending that type. Therefore there must be something which 'knows' about the contents or purposes of the arguments. That thing would have to be more than just a basic type, because the basic types are either containers which don't know about their contents, or they are single objects which can't capture their relationship with their fellows of the same type. So, this thing with the extra knowledge should be reified into a class, and the utility method will most likely belong there.
Example
Running Reek on:
class Warehouse
def sale_price(item)
(item.price - item.rebate) * @vat
end
end
would report:
Warehouse#total_price refers to item more than self (FeatureEnvy)
since this:
(item.price - item.rebate)
belongs to the Item class, not the Warehouse.
Cinch::Plugins::DevTools#command_resources contains iterators nested 2 deep Open
objects_in(root_object).select do |obj|
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A Nested Iterator
occurs when a block contains another block.
Example
Given
class Duck
class << self
def duck_names
%i!tick trick track!.each do |surname|
%i!duck!.each do |last_name|
puts "full name is #{surname} #{last_name}"
end
end
end
end
end
Reek would report the following warning:
test.rb -- 1 warning:
[5]:Duck#duck_names contains iterators nested 2 deep (NestedIterators)
Cinch::Plugins::DevTools#each_plugin contains iterators nested 2 deep Open
each_plugin_named(plugin_name) do |root_object, plugin_name|
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A Nested Iterator
occurs when a block contains another block.
Example
Given
class Duck
class << self
def duck_names
%i!tick trick track!.each do |surname|
%i!duck!.each do |last_name|
puts "full name is #{surname} #{last_name}"
end
end
end
end
end
Reek would report the following warning:
test.rb -- 1 warning:
[5]:Duck#duck_names contains iterators nested 2 deep (NestedIterators)
Cinch::Plugins::DevTools#command_all_resources has approx 10 statements Open
def command_all_resources(m)
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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.)
Cinch::Plugins::DevTools#command_resources calls 'obj.class.name' 2 times Open
!(['Class', 'Cinch::Bot'].include? obj.class.name)
end.each do |obj|
m.reply " #{Format(:bold, obj.class.name.to_s)}: #{total_memory_for obj}"
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Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.
Reek implements a check for Duplicate Method Call.
Example
Here's a very much simplified and contrived example. The following method will report a warning:
def double_thing()
@other.thing + @other.thing
end
One quick approach to silence Reek would be to refactor the code thus:
def double_thing()
thing = @other.thing
thing + thing
end
A slightly different approach would be to replace all calls of double_thing
by calls to @other.double_thing
:
class Other
def double_thing()
thing + thing
end
end
The approach you take will depend on balancing other factors in your code.
Cinch::Plugins::DevTools#highlight_value calls 'value.to_s' 4 times Open
Format(:red, value.to_s)
elsif value > average + standard_deviation
Format(:orange, value.to_s)
elsif value > average + standard_deviation / 2
Format(:yellow, value.to_s)
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- Exclude checks
Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.
Reek implements a check for Duplicate Method Call.
Example
Here's a very much simplified and contrived example. The following method will report a warning:
def double_thing()
@other.thing + @other.thing
end
One quick approach to silence Reek would be to refactor the code thus:
def double_thing()
thing = @other.thing
thing + thing
end
A slightly different approach would be to replace all calls of double_thing
by calls to @other.double_thing
:
class Other
def double_thing()
thing + thing
end
end
The approach you take will depend on balancing other factors in your code.
Cinch::Plugins::DevTools#command_resources calls 'obj.class' 2 times Open
!(['Class', 'Cinch::Bot'].include? obj.class.name)
end.each do |obj|
m.reply " #{Format(:bold, obj.class.name.to_s)}: #{total_memory_for obj}"
- Read upRead up
- Exclude checks
Duplication occurs when two fragments of code look nearly identical, or when two fragments of code have nearly identical effects at some conceptual level.
Reek implements a check for Duplicate Method Call.
Example
Here's a very much simplified and contrived example. The following method will report a warning:
def double_thing()
@other.thing + @other.thing
end
One quick approach to silence Reek would be to refactor the code thus:
def double_thing()
thing = @other.thing
thing + thing
end
A slightly different approach would be to replace all calls of double_thing
by calls to @other.double_thing
:
class Other
def double_thing()
thing + thing
end
end
The approach you take will depend on balancing other factors in your code.
Cinch::Plugins::DevTools has no descriptive comment Open
class DevTools
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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
Cinch::Plugins::DevTools#average_usage doesn't depend on instance state (maybe move it to another class?) Open
def average_usage(stats)
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A Utility Function is any instance method that has no dependency on the state of the instance.
Cinch::Plugins::DevTools#plugins doesn't depend on instance state (maybe move it to another class?) Open
def plugins
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A Utility Function is any instance method that has no dependency on the state of the instance.
Cinch::Plugins::DevTools#objects_in doesn't depend on instance state (maybe move it to another class?) Open
def objects_in(root_object)
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A Utility Function is any instance method that has no dependency on the state of the instance.
Cinch::Plugins::DevTools#plugin_for doesn't depend on instance state (maybe move it to another class?) Open
def plugin_for(plugin_name)
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A Utility Function is any instance method that has no dependency on the state of the instance.
Cinch::Plugins::DevTools#command_list_plugins has the parameter name 'm' Open
def command_list_plugins(m)
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An Uncommunicative Parameter Name
is a parameter 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.
Cinch::Plugins::DevTools#command_all_resources has the parameter name 'm' Open
def command_all_resources(m)
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An Uncommunicative Parameter Name
is a parameter 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.
Cinch::Plugins::DevTools#command_resources has the parameter name 'm' Open
def command_resources(m, plugin_name)
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An Uncommunicative Parameter Name
is a parameter 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.
Ambiguous regexp literal. Parenthesize the method arguments if it's surely a regexp literal, or add a whitespace to the right of the /
if it should be a division. Open
match /resources\s*$/i, :method => :command_all_resources
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- Exclude checks
This cop checks for ambiguous regexp literals in the first argument of a method invocation without parentheses.
Example:
# bad
# This is interpreted as a method invocation with a regexp literal,
# but it could possibly be `/` method invocations.
# (i.e. `do_something./(pattern)./(i)`)
do_something /pattern/i
Example:
# good
# With parentheses, there's no ambiguity.
do_something(/pattern/i)
Ambiguous regexp literal. Parenthesize the method arguments if it's surely a regexp literal, or add a whitespace to the right of the /
if it should be a division. Open
match /resources\s+(.*)\s*$/i, :method => :command_resources
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- Exclude checks
This cop checks for ambiguous regexp literals in the first argument of a method invocation without parentheses.
Example:
# bad
# This is interpreted as a method invocation with a regexp literal,
# but it could possibly be `/` method invocations.
# (i.e. `do_something./(pattern)./(i)`)
do_something /pattern/i
Example:
# good
# With parentheses, there's no ambiguity.
do_something(/pattern/i)
Shadowing outer local variable - plugin_name
. Open
each_plugin_named(plugin_name) do |root_object, plugin_name|
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This cop looks for use of the same name as outer local variables
for block arguments or block local variables.
This is a mimic of the warning
"shadowing outer local variable - foo" from ruby -cw
.
Example:
# bad
def some_method
foo = 1
2.times do |foo| # shadowing outer `foo`
do_something(foo)
end
end
Example:
# good
def some_method
foo = 1
2.times do |bar|
do_something(bar)
end
end
Ambiguous regexp literal. Parenthesize the method arguments if it's surely a regexp literal, or add a whitespace to the right of the /
if it should be a division. Open
match /plugins\s*$/i, :method => :command_list_plugins
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- Exclude checks
This cop checks for ambiguous regexp literals in the first argument of a method invocation without parentheses.
Example:
# bad
# This is interpreted as a method invocation with a regexp literal,
# but it could possibly be `/` method invocations.
# (i.e. `do_something./(pattern)./(i)`)
do_something /pattern/i
Example:
# good
# With parentheses, there's no ambiguity.
do_something(/pattern/i)
Shadowing outer local variable - plugin_name
. Open
each_plugin_named(plugin_name) do |root_object, plugin_name|
- Read upRead up
- Exclude checks
This cop looks for use of the same name as outer local variables
for block arguments or block local variables.
This is a mimic of the warning
"shadowing outer local variable - foo" from ruby -cw
.
Example:
# bad
def some_method
foo = 1
2.times do |foo| # shadowing outer `foo`
do_something(foo)
end
end
Example:
# good
def some_method
foo = 1
2.times do |bar|
do_something(bar)
end
end