CODEWITHSUNDEEP
ruby-on-railsrubyrubygems
dosuken123
dosuken123

Reputation: 468

How to analyze quickly the code definition from a given code

Let's say I'm in a really huge project and am curious how this line works:

authorize! :read_pipeline_schedule, user_project

authorize! is supposed to be method name. Is it a private function in the class, or DSL provided from a parent block, or including, or declared in a gem? Or maybe none of them?

I was using grep to find internal code and Google for external code such as gems, however I guess it's useful if I can see the call stack of the method. puts caller is printing from the place where I am although it can not be used for analyzing the above case.

I'd like to know the best practice.

Upvotes: 2

Views: 46

Answers (3)

Josh Brody
Josh Brody

Reputation: 5363

I like caller(0), caller_locations, and the ever-incredible show-source

Upvotes: 0

Jörg W Mittag
Jörg W Mittag

Reputation: 369556

The easiest way is to ask the method itself:

method_object = method(:authorize!)

method_object.owner
# => returns module in which the method resides

method_object.source_location
# => returns file name and line number of source code where the method is defined

Note that source_location may return nil for methods which have no Ruby source code, e.g. dynamically generated methods or methods implemented in the interpreter internals (C functions in YARV, Java methods in JRuby, etc.)

Upvotes: 0

Sergio Tulentsev
Sergio Tulentsev

Reputation: 230521

You can grep your code and installed gems and, if name is unique enough, you'll quickly locate its definition and associated usages. However, if a name is a common one, like call, then this approach is useless.

Ruby is a dynamic language and, as such, is a nightmare for static analysis. You may guess where this comes from, but you just can't know for sure.

The only way to know is runtime introspection. So, in your example, put a breakpoint right before that line

binding.pry
authorize! :read_pipeline_schedule, user_project

You'll drop out to pry shell. Now you can do 

show-source authorize!

And see where exactly this method is defined.

Upvotes: 6

Related Questions