https://github.com/camertron/absolver

Allows setting the cause of Ruby exceptions.
https://github.com/camertron/absolver

Last synced: 18 days ago
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Allows setting the cause of Ruby exceptions.

• Host: GitHub
• URL: https://github.com/camertron/absolver
• Owner: camertron
• License: mit
• Created: 2019-02-27T17:45:52.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2019-02-27T18:00:45.000Z (almost 6 years ago)
• Last Synced: 2024-04-25T07:22:25.154Z (9 months ago)
• Language: Ruby
• Size: 3.91 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
absolver

===

Absolver is a small little gem that allows setting the cause of a Ruby exception. Consider this example:

```ruby

err = begin

  begin

    1 / 0

  rescue => e

    raise RuntimeError, 'foo'

  end

rescue => e

  e

end

```

Notice that I raised a `RuntimeError` _inside_ a `rescue` block. In Ruby 2.1 and later, doing so will set the inner exception's `#cause` attribute to the outer exception. In other words:

```ruby

err        # => #

err.cause  # => #

```

Cool, thanks Ruby!

What if I want to change the cause though? Maybe I don't really want to include the cause when reporting to an external error monitoring service, for example. Sadly, Ruby doesn't let you do that:

```ruby

err.cause = nil

# NoMethodError (undefined method `cause=' for #)

```

What's a programmer to do? Use absolver!

```ruby

require 'absolver'

Absolver.set_cause(err, nil)

err.cause  # => nil

```

Absolver uses [Fiddle](https://ruby-doc.org/stdlib-2.5.0/libdoc/fiddle/rdoc/Fiddle.html) to safely set the `cause` attribute of the `Exception` object. Basically it reaches down into Ruby's internals to adjust the value of the `cause` instance variable, which normally isn't exposed to your program.

Absolver also includes a small monkeypatch that adds `cause=` to `Exception`. Because many people dislike monkeypatches, you have to opt-in:

```ruby

require 'absolver/exception'

err.cause = nil

```

## License

Licensed under the MIT license. See LICENSE for details.

## Authors

* Cameron C. Dutro: http://github.com/camertron