How to set the condition of conditional breakpoints in Swift with self and enum?

Question

I have a enum of HTTP methods:

enum HTTPMethod: String {
  case GET = "GET"
  case POST = "POST"
}

and I have a request class and a request wrapper class:

class Request {
  let method: HTTPMethod = .GET
}

class RequestWrapper {
  let request: Request

  func compareToRequest(incomingRequest: NSURLRequest) -> Bool {

     // Next line is where the conditional breakpoint set.
     return request.method.rawValue == incomingRequest.HTTPMethod
  }
}

I set a conditional breakpoint on the line:

return request.method.rawValue == incomingRequest.HTTPMethod

with condition:

self.request.method == HTTPMethod.POST

and then the debugger stop at the line with an error message:

Stopped due to an error evaluating condition of breakpoint 1.1:     
"self.request.method == HTTPMethod.POST"
Couldn't parse conditional expression:
<EXPR>:1:1: error: use of unresolved identifier 'self'
self.request.HTTPMethod == HTTPMethod.POST

And if I delete self and change the condition to:

request.method == HTTPMethod.POST

Error message is as the following lines:

Stopped due to an error evaluating condition of breakpoint 1.1:  
"request.method == HTTPMethod.POST"
Couldn't parse conditional expression:
<EXPR>:1:1: error: could not find member 'method'
request.method == HTTPMethod.POST
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Is there a way to solve this question?

Update:

It's able to check the value of self.request.method using LLDB command:

fr v self.request.method

And if I use a local constant to store the value, the debugger can be stopped at the right position:

// Use a local constant to store the HTTP method
let method = request.method

// Condition of breakpoint
method == HTTPMethod.POST

Update 2:

I am using Xcode 6.3.1

Answer 1

This is pretty clearly an lldb bug. You don't mention what version of the tools you are using. If you aren't using 6.3.1 or better, please try again using that. If you are still seeing a problem, please file a bug with http://bugreporter.apple.com.

Note, frame var and expr are pretty different beasts. frame var only prints the values of local variables, using the DWARF debug information directly, but is NOT an expression evaluator. So for instance, it doesn't know enough to do ==. I imagine if you did:

(lldb) self.request.method == HTTPMethod.POST

when stopped at that breakpoint you would see the same effect.

The expression parser has to play the extra trick of posing as a method of your class (to get transparent references through self, etc to work) and, it is a little tricky to get that right. Apparently we aren't doing the job correctly in your case.