Analisando Complexidade de Código Ruby

Analisando Complexidade de Código Ruby Utilizando Métricas para Encontrar Código que Fede Cássio Marques RubyMasters Conf 2011Saturday, February 26, 2011

Cássio Marques • código + comida vegan + livros + skate + música • Taoweb • Lime • http://cassiomarques.wordpress.com • @cassiomarquesSaturday, February 26, 2011

Porque analisar o código?Saturday, February 26, 2011

http://www.ﬂickr.com/photos/rovingi/312078231/Saturday, February 26, 2011

Como analisar o código?Saturday, February 26, 2011

EstéticaSaturday, February 26, 2011

Diﬁculdade de ManutençãoSaturday, February 26, 2011

ChuteSaturday, February 26, 2011

AbstraçõesSaturday, February 26, 2011

MétricasSaturday, February 26, 2011

Medir alguma propriedade especíﬁca do códigoSaturday, February 26, 2011

Objetivo: Quantiﬁcar o que antes era abstratoSaturday, February 26, 2011

Métrica ABCSaturday, February 26, 2011

Analisa ComplexidadeSaturday, February 26, 2011

ﬂog github.com/seattlerb/ﬂogSaturday, February 26, 2011

Assignement Deﬁnir o valor de uma variável explicitamenteSaturday, February 26, 2011

= += *= << /= etc... -=Saturday, February 26, 2011

Branching Criar um novo ﬂuxo de execuçãoSaturday, February 26, 2011

if or else rescue elsif (argh!) until case while andSaturday, February 26, 2011

Calls Chamadas a métodosSaturday, February 26, 2011

(Outras implementações usam Condition)Saturday, February 26, 2011

|ABC| = sqrt((A*A)+(B*B)+(C*C))Saturday, February 26, 2011

Mas em Ruby temos mais do que isso!Saturday, February 26, 2011

eval & cia (pontuação alta!!!) deﬁne_method eval module_eval class_eval instance_evalSaturday, February 26, 2011

blocos/yieldSaturday, February 26, 2011

Introspecção instance_method method_deﬁned? private_instance_method privante_class_method public_instance_method etc...Saturday, February 26, 2011

Hooks Module#included Module#extended Class#inherited method_deﬁned etc...Saturday, February 26, 2011

Ou seja...Saturday, February 26, 2011

Ou seja... METAPROGRAMAÇÃO É COMPLEXO E DIFICULTA A MANUTENÇÃO DO CÓDIGOSaturday, February 26, 2011

Quando veriﬁcar isso no seu código?Saturday, February 26, 2011

FrequentementeSaturday, February 26, 2011

(já deixei para a fase ﬁnal de um projeto e o resultado foi traumático)Saturday, February 26, 2011

Complexidade CiclomáticaSaturday, February 26, 2011

saikuro http://saikuro.rubyforge.org/Saturday, February 26, 2011

Mede o número de segmentos linearmente independentes na execução do códigoSaturday, February 26, 2011

Grafo direcionado para representar os caminhos de execuçãoSaturday, February 26, 2011

1 def some_method(value) 2 if value % 2 == 0 3 value.times { |i| puts i } 4 else 5 while value >= 0 6 puts value 7 value -= 1 8 end 9 end 10 endSaturday, February 26, 2011

Início value % 2 == 0 value.times { |i| ... while value >= 0 puts value puts i puts value -= 1 FimSaturday, February 26, 2011

C = A - V + 2P C => Complexidade ciclomática A => Número de arestas V => Número de vértices P => Número de componentes conectadosSaturday, February 26, 2011

Pode ser utilizada para deﬁnir o número de casos de teste necessários para ter total cobertura do códigoSaturday, February 26, 2011

Métrica procedural, mas pode ser usada em código OO no escopo de métodosSaturday, February 26, 2011

Duplicação de códigoSaturday, February 26, 2011

ﬂay http://ruby.sadi.st/Flay.htmlSaturday, February 26, 2011

Pesquisa por códigos SEMELHANTESSaturday, February 26, 2011

Resultados são bons candidatos para refactoringSaturday, February 26, 2011

Código que muda com muita frequênciaSaturday, February 26, 2011

churn github.com/danmayer/churnSaturday, February 26, 2011

Código que muda muito == problemasSaturday, February 26, 2011

Indica quantidade de alterações ao longo do tempoSaturday, February 26, 2011

Métodos Classes ArquivosSaturday, February 26, 2011

git/mercurialSaturday, February 26, 2011

Code SmellsSaturday, February 26, 2011

Sintoma que indica algum problema mais sérioSaturday, February 26, 2011

O código pode feder por vários motivosSaturday, February 26, 2011

reek github.com/kevinrutherford/reekSaturday, February 26, 2011

Aceita opções sobre quais smells identiﬁcar/ ignorarSaturday, February 26, 2011

AtributosSaturday, February 26, 2011

readers/writers (ou getters/setters) podem expor demais seus objetosSaturday, February 26, 2011

Variáveis de ClasseSaturday, February 26, 2011

1 class MyClass 2 @@my_class_variable = 1 3 4 class << self 5 attr_accessor :my_other_class_variable 6 end 7 endSaturday, February 26, 2011

Aumenta o escopo globalSaturday, February 26, 2011

Classe LongaSaturday, February 26, 2011

Muitas linhasSaturday, February 26, 2011

Muitas variáveis de instânciaSaturday, February 26, 2011

Muitos métodosSaturday, February 26, 2011

*provavelmente* fazendo coisa demais!Saturday, February 26, 2011

Método LongoSaturday, February 26, 2011

Lista de Parâmetros LongaSaturday, February 26, 2011

1 def pay_with_credit_card(number, security_code, holder_name, expiration, value) 2 # ... 3 endSaturday, February 26, 2011

Possíveis soluçõesSaturday, February 26, 2011

Passar um hashSaturday, February 26, 2011

Encapsular em um objetoSaturday, February 26, 2011

Baixa Coesão Feature EnvySaturday, February 26, 2011

1 class Cart 2 def price 3 @item.price + @item.tax 4 end 5 endSaturday, February 26, 2011

Baixa Coesão Utility FunctionSaturday, February 26, 2011

Método que não depende do estado do objetoSaturday, February 26, 2011

1 class Oven 2 def formatted_temperature(sensor) 3 "#{sensor.temperature} #{sensor.unit}" 4 end 5 endSaturday, February 26, 2011

Polimorﬁsmo SimuladoSaturday, February 26, 2011

1 def some_method(value) 2 if value > 10 3 if value < 20 4 if value != 15 5 puts "duh" 6 else 7 puts "meh" 8 end 9 end 10 end 11 endSaturday, February 26, 2011

switch também :) (o reek ainda não identiﬁca)Saturday, February 26, 2011

Uncommunicative NamesSaturday, February 26, 2011

Nomes não reﬂetem a intenção do códigoSaturday, February 26, 2011

1 class SomeClass 2 def some_method 3 # ... 4 end 5 6 def some_method_2 7 # ... 8 end 9 10 def another_method 11 a = 10 12 aLocalVariable = 25 13 end 14 endSaturday, February 26, 2011

Pode ser conﬁgurado com uma lista de regexps default [/^.[0-9]*$/]Saturday, February 26, 2011

Cobertura de TesteSaturday, February 26, 2011

!= “bem testado”Saturday, February 26, 2011

rcov http://eigenclass.org/hiki.rb?rcovSaturday, February 26, 2011

Pode indicar trechos do código que foram negligenciadosSaturday, February 26, 2011

Too Simple To BreakSaturday, February 26, 2011

Novas funcionalidades são adicionadas, mas continua sem testesSaturday, February 26, 2011

Saturday, February 26, 2011

Outros smells e erros de estiloSaturday, February 26, 2011

roodi github.com/martinjandrews/roodiSaturday, February 26, 2011

Atribuição de valor dentro de uma estrutura condicionalSaturday, February 26, 2011

1 # Deveria ser foo == 100 2 if foo = 100 3 # ... 4 endSaturday, February 26, 2011

1 # Falso positivo... 2 def some_method(value) 3 if @value = value 4 # ... 5 end 6 endSaturday, February 26, 2011

case sem cláusula elseSaturday, February 26, 2011

1 def some_method(value) 2 case value 3 when 1..10 4 puts "Entre 1 e 10" 5 when 11..20 6 puts "Entre 11 e 20" 7 end 8 endSaturday, February 26, 2011

Classes com muitas linhas de código (por padrão limita em 300)Saturday, February 26, 2011

Padrão para nome de classes e módulos (veriﬁca se o nome das classes e módulos está em CamelCase)Saturday, February 26, 2011

cláusulas rescue vaziasSaturday, February 26, 2011

1 def calculate_factor(number) 2 begin 3 SOME_CONSTANT / number 4 rescue 5 6 end 7 endSaturday, February 26, 2011

1 def calculate_factor(number) 2 begin 3 SOME_CONSTANT / number 4 rescue => e 5 # Tratar a exceção de alguma forma... 6 end 7 endSaturday, February 26, 2011

Uso de loops com forSaturday, February 26, 2011

1 def print_list(list) 2 for value in list do 3 puts value 4 end 5 endSaturday, February 26, 2011

1 def print_list(list) 2 list.each {|value| puts value } 3 endSaturday, February 26, 2011

Métodos com muitas linhas de código (por padrão limita em 20)Saturday, February 26, 2011

Padrão para nomes de métodos (veriﬁca se os nomes dos métodos estão snake_case)Saturday, February 26, 2011

rails_best_practices github.com/ﬂyerhzm/rails_best_practicesSaturday, February 26, 2011

Ok...Saturday, February 26, 2011

Mas é muita coisa para gerenciar!Saturday, February 26, 2011

metric_fu http://metric-fu.rubyforge.org/Saturday, February 26, 2011

saikuro + ﬂog + ﬂay + rcov + reek + roodi + churn + rails_best_practicesSaturday, February 26, 2011

rake metrics:allSaturday, February 26, 2011

Integração ContínuaSaturday, February 26, 2011

Métricas ao longo do tempoSaturday, February 26, 2011

Relatórios!Saturday, February 26, 2011

Saturday, February 26, 2011

Problema:Saturday, February 26, 2011

O metric_fu acaba virando uma dependência do seu projetoSaturday, February 26, 2011

metrical github.com/iain/metricalSaturday, February 26, 2011

$ gem install metrical $ cd /path/of/your/project $ metricalSaturday, February 26, 2011

Dúvidas?Saturday, February 26, 2011

Obrigado!Saturday, February 26, 2011

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Analisando Complexidade de Código Ruby

by cassiomarques on Feb 26, 2011

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