Add meta data interface and trait

[migo315]

Goal

Provide a very simple way to extend an exception with additional meta data everywhere without further dependencies.

Design

This feature is very pragmatic and straightforward. Similar to PSR Logger, we provide a MetaDataAwareInterface and a MetaDataAwareTrait. The developer can (but must not) extend his Exceptions with the Interface / Trait to add some additional informations:

class UnrecoverableProcessException extends Exception implements MetaDataAwareInterface
{
    use MetaDataAwareTrait;
}

Later just pass your informations:

$exception = new UnrecoverableProcessException('I am an Exception');
$exception->addMetaData(['myTab' => [
    'foo' => 'bar',
]]);

throw $exception;

This implementation does not need any services or heavy structures.

Changeset

Added

• MetaDataAwareInterface
• MetaDataAwareTrait

Changed

• Client add MetaData if Exception implements interface

Linked issues

Original PR: bugsnag/bugsnag-symfony#83

Review

For the submitter, initial self-review:

• Commented on code changes inline explain the reasoning behind the approach
• [] Reviewed the test cases added for completeness and possible points for discussion
• A changelog entry was added for the goal of this pull request
• Check the scope of the changeset - is everything in the diff required for the pull request?
• This pull request is ready for:
  • Initial review of the intended approach, not yet feature complete
  • Structural review of the classes, functions, and properties modified
  • Final review

For the pull request reviewer(s), this changeset has been reviewed for:

• Consistency across platforms for structures or concepts added or modified
• Consistency between the changeset and the goal stated above
• Internal consistency with the rest of the library - is there any overlap between existing interfaces and any which have been added?
• Usage friction - is the proposed change in usage cumbersome or complicated?
• Performance and complexity - are there any cases of unexpected O(n^3) when iterating, recursing, flat mapping, etc?
• Concurrency concerns - if components are accessed asynchronously, what issues will arise
• Thoroughness of added tests and any missing edge cases
• Idiomatic use of the language

[GrahamCampbell]

This should probably be implemented by a middleware, rather than being baked into the client like this.

[migo315]

I'm not that familiar with this SDK. But the middleware doesn't get any exceptions, does it?

[GrahamCampbell]

Yeh, that is correct. Maybe we should change the report object to keep the actual exception around, so people can grab it (by means of a method on the report object that returns the exception or null).

[GrahamCampbell]

Yeh, that is correct. Maybe we should change the report object to keep the actual exception around, so people can grab it (by means of a method on the report object that returns the exception or null).

[johnkiely1]

This has now been fixed via bugsnag-php release V3.21.0
https://github.com/bugsnag/bugsnag-php/releases/tag/v3.21.0.
running composer update bugsnag/bugsnag will pull in latest version

We have added support for the getting the original error on which you can attach additional metadata.