Truncate project_root prefix from filename

[eagletmt]

Especially in Rails project, when an exception is raised in view template, the filename is always full path.
With capistrano (de-facto standard for Ruby application deployment), the full path differs on each release.
It causes Sentry to recognize the same error differently.

[seanlinsley]

Hmm, my Rails application uses Capistrano and doesn't have an issue with Sentry failing to group events.

[eagletmt]

Hmm... my Rails application always says the filename is /path/to/deploy/directory/releases/$TIMESTAMP/app/views/foo/bar.html.erb .

Even if the filename was /path/to/deploy/directory/current, truncating meaningless part would be better.

[seanlinsley]

What version of Rails and Capistrano are you using?

[eagletmt]

• Rails 4.2.0 + Capistrano 3.3.5 https://github.com/eagletmt/ttcoder
• Several Rails 3.2, 4.1 + Capistrano 2.x, 3.x applications at work

[seanlinsley]

I'm using Rails 4.1 with Capistrano 2.15.5

[eagletmt]

Again, even if the filename was /path/to/deploy/directory/current/app/views/foo/bar.html.erb , truncating meaningless part would be better.
app/views/foo/bar.html.erb is a familiar form to Rails users.

Model's or controller's filename is book.rb or books_controller.rb in Rails project.
Only view templates have full path currently.

[nateberkopec]

@dcramer Should Sentry be able to correctly group the case described here?

[nateberkopec]

Sorry, but I think we have to keep abs_path as the actual absolute path to stay on spec. If you think there's an issue with how Sentry groups events together, please open that issue on the main Sentry server repository.

[nateberkopec]

Hmm not sure I quite understood this PR, you weren't actually changing abs_path, you were changing filename!

[dannyfallon]

👍 @eagletmt, this is precisely what I was getting at in the issue

[nateberkopec]

This self is unnecessary.

[nateberkopec]

Confusing I know since we use it everywhere else in this method.

[nateberkopec]

@eagletmt If you could please rebase against master, I can merge.

[eagletmt]

@nateberkopec rebased.