TYPO3 Core

I think it should be possible for each validator to add custom error messages, because the default messages are very technical.

I will work on this and make a change request.

Which version of TYPO3 you use? There was a bug in 8.5 (i think). The original validator messages was choosen insteed of the custom ext:form ones.

Each validator message can be customized with own tranlations. The translations can reside within xliff files or defined with TypoScript.
Each validator messages can be overridden 'form wide' for a special form or for the combination special form - form element.
There is a related pending patchset https://review.typo3.org/#/c/52008/.
If this is enough for you, you don't need to spend time to work on this.

The mentioned patch looks very promising, when we talk about predefined forms. Though it does help use here.

This it is more about editors building forms them selves with the wizard. Most editors cannot use some strange looking xml translations files. Therefore should it be possible to define the message in the wizard.

This feature request is about the form editor not about predefined forms. See first sentence of description.

The point is that a user must be told what went wrong. Neither a vague "there is an error in your input" nor "your input doesn't match regular expression /a.*b/" is helpful.

Unless this issue has been addressed I wouldn't allow editors to configure a regexp validator.

As Martin says, the form wizard is not of much use, if editors can not define the error messages.

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 4 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 5 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 6 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 7 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 8 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 9 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 10 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 11 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 12 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 13 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 14 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 15 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 16 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 17 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 18 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 19 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 20 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 21 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 22 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 23 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 24 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 25 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 26 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 27 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 28 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 29 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078

Patch set 30 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/52078