From: yorickpeterse@...
Date: 2015-02-03T22:27:27+00:00
Subject: [ruby-core:67986] [ruby-trunk - Bug #10561] Improve function of Thread::Backtrace::Location #path and #absolute_path

Issue #10561 has been updated by Yorick Peterse.


Nobu: I talked about this with Koichi today after noticing you added tests for
path/absolute_path after my talk at FOSDEM. Since these tests assert that path
returns the full path I'd like to know which one is correct.

Is it this:

    caller_locations[0].path # => "example.rb"

Or is this the correct way:

    caller_locations[0].path # => "/home/some-user/example.rb"

If the last example is correct, is it perhaps an idea to add "basename" to
Thread::Location::Backtrace, which would return _just_ the filename, and make
path an alias to absolute_path? So:

    caller_locations[0].path          # => "/home/some-user/example.rb"
    caller_locations[0].absolute_path # => "/home/some-user/example.rb"
    caller_locations[0].basename      # => "example.rb"

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Bug #10561: Improve function of Thread::Backtrace::Location #path and #absolute_path
https://bugs.ruby-lang.org/issues/10561#change-51373

* Author: Sam Saffron
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: 2.2.0
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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I was working on this issue in Rails and hit an area where Backtrace Location can be improved

https://github.com/rails/rails/pull/17782


1. It is undefined in the documentation how #absolute_path should operate when #path is invalid (in case of instance eval)
2. There are a few conditions where #path and #absolute_path can return nil, this forces extra protection code when parsing paths to check for nil. (for example getting filename)  

Suggestions:

1. Instead of returning Qnil from location_path and location_absolute_path on invalid conditions, return the string "(unknown)" which is easier to parse and sticks out better in a big backtrace. There is precedent here with the string "(eval)"
2. If path is invalid have absolute_path return "(unknown)", define that in the documentation
3. (possible) add an additional method on caller_location called #filename so people stop parsing filename from #path and #absolute_path
4. Evaluate if it makes sense to have #path and #absolute_path in the API as both methods can return full paths so the semantic difference is subtle. 



-- 
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