具有任務依賴關係的Rake規則

Question

我試圖制定一個取決於另一個任務的rake規則。它的工作原理如下圖所示，如果我只用任務：

task :foo do 
    @iv = 42 
end 

task :bar => :foo do 
    p @iv 
end 

Rake::Task[:bar].invoke 

結果：

42 

我希望能夠使用規則，所以我可以使用正則表達式。但我發現了一個錯誤：

task :foo do 
    @iv = 42 
end 

rule /bar/ => :foo do 
    p @iv 
end 

Rake::Task["bar"].invoke 

結果：

/Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:284:in `block in make_sources': Don't know how to handle rule dependent: :foo (RuntimeError) 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:267:in `map' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:267:in `make_sources' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:245:in `attempt_rule' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:130:in `block in enhance_with_matching_rule' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:128:in `each' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:128:in `enhance_with_matching_rule' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task_manager.rb:56:in `[]' 
    from /Users/max/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/rake-12.0.0/lib/rake/task.rb:361:in `[]' 
    from baz.rb:63:in `<main>' 

如何使用依賴於其他任務的規則？

編輯：

由於此規則下面提到需要它的依賴作爲一個字符串：

task :foo do 
    @iv = 42 
end 

rule /bar/ => "foo" do 
    p @iv 
end 

Rake::Task["bar"].invoke 
#=> 42 

Answer 1

變化:foo到"foo"解決了這個問題。

看來task_manager.rb#make_sources不處理符號。

https://github.com/ruby/rake/blob/master/lib/rake/task_manager.rb#L266,L288