Given I know where a method is defined, I want to know where its called (at runtime)

Rails
1

Hey all, application completely breaks down in production mode. I
followed the execution file by file line by line and yet I cannot figure
out where an instance variable is being generated from. But I have a
suspicion. This method right here:

neeeded becasuse of a rails bug

def to_s
“#{self.class.name.underscore}__#{object_id}”
end

I think it’s cause of problem. I also noticed that the developer left a
comment above it. Problem is it’s part of a class that gets yielded into
a ruby block and there’s a number of partials that get rendered in the
new view. But I cannot find for the life of me where to_s is called
during execution of clicking a new button.

I need some debugging advice for this.

Thanks for response.

2

On May 4, 2011, at 6:39 PM, John M. wrote:

I think it’s cause of problem. I also noticed that the developer left a
comment above it. Problem is it’s part of a class that gets yielded into
a ruby block and there’s a number of partials that get rendered in the
new view. But I cannot find for the life of me where to_s is called
during execution of clicking a new button.

I need some debugging advice for this.

caller() should help…

http://www.ruby-doc.org/core/classes/Kernel.html#M001397

3

Philip H. wrote in post #996721:

On May 4, 2011, at 6:39 PM, John M. wrote:

I think it’s cause of problem. I also noticed that the developer left a
comment above it. Problem is it’s part of a class that gets yielded into
a ruby block and there’s a number of partials that get rendered in the
new view. But I cannot find for the life of me where to_s is called
during execution of clicking a new button.

I need some debugging advice for this.

caller() should help…

module Kernel - RDoc Documentation

It appears caller expects an argument. This is not a setter method.
There is no argument passed to this object, and in your example, if i
add one like ‘skip’, of course I receive an exception “wrong number of
arguments”.

4

On 5 May 2011 02:39, John M. [email protected] wrote:

I think it’s cause of problem. I also noticed that the developer left a
comment above it. Problem is it’s part of a class that gets yielded into
a ruby block and there’s a number of partials that get rendered in the
new view. But I cannot find for the life of me where to_s is called
during execution of clicking a new button.

I need some debugging advice for this.

If all else fails put some code there that generates a runtime error,
then you will get a stack trace. If you only want it to stop under
some conditions use a global variable and test it at the offending
point to find out whether to crash or not.

Fred’s suggestion of using ruby-debug and putting a (possibly
conditional) breakpoint there is probably better.

Colin

5

The argument to caller is optional. You might also want to install
ruby-debug and add a breakpoint.

Fred

Yeah kind of like breakpoint in C++. Thanks for response.

6

On 5 May 2011, at 03:04, John M. [email protected] wrote:

caller() should help…

module Kernel - RDoc Documentation

It appears caller expects an argument. This is not a setter method.
There is no argument passed to this object, and in your example, if i
add one like ‘skip’, of course I receive an exception “wrong number of
arguments”.

The argument to caller is optional. You might also want to install
ruby-debug and add a breakpoint.

Fred