DOC Show more information in ValidationException message

[emteknetnz]

Issue silverstripe/silverstripe-framework#11423

[GuySartorelli]

Probably worth adding a note that out of the box the only validation messages which have this additional context are ones produced by a call to DataObject::validate().

Also add some docs around the new API in the validation documentation section.

[emteknetnz]

Also add some docs around the new API in the validation documentation section.

I don't know how to do this. The most relevant section would be here

We could add something like this, but it seems like far too much basically irrelevant detail

DataObject::validate() will also call ValidationResult::setModelClass() and ValidationResult::setRecordID() with static::class and $this->ID respectively, this is done to provide context to the validation result and will be used to update the error messages with the model class and record ID when in a CLI context, or when the current controller is DevelopmentAdmin i.e. the controller used when running dev/build.

[GuySartorelli]

I'm not saying we should document what DataObject does - but we should document that developers can call setModelClass() and setRecordID() on their own validation result instances in order to provide that information which will then be included in the ValidationException.

I wonder if we should also provide setModelClass() and setRecordID() for the exception class itself, so that direct validation exceptions don't have to have a validation result object to benefit from that? But that's just an idle thought that you can feel free to ignore if you wish.

[emteknetnz]

Updated

[GuySartorelli]

LGTM, will merge after code PRs