Deprecate RegexField.error_message

[Baptiste Mispelon]

Unlike other fields, RegexField takes an error_message argument (as opposed to the error_messages argument other fields take).

It seems this was done to maintain backwards compatibility with the pre-1.0 releases [1].

This argument is documented (and somewhat tested) but the documentation states that this is not the preferred way to do it (the preferred way being to use error_messages={'invalid': '...'}).

I propose we move through the deprecation procedure and remove that argument altogether.

Note that this feature is still used in django.contrib.flatpages.forms so this will also need to be changed over to the new and preferred syntax.

I'm marking the ticket as easy_pickings since the removal should be quite straightforward.

[1] ​https://github.com/django/django/commit/26ea06b0ab423348e40652dd9e3f530a08b93582#diff-2141c7b3d1c360359d58d724553afd06R377

[Tim Graham]

​PR

[Baptiste Mispelon]

Left two minor comments on the PR.

Looks ready for checkin otherwise.

Thanks!

[Tim Graham <timograham@…>]

In 0f2ceee0254349ee4ac7d472d3efe67ee161a917:

Fixed #23151 -- Deprecated RegexField.error_message.

Thanks Baptiste Mispelon for the suggestion.

[Tim Graham <timograham@…>]

In b6ea1961:

Refs #23151 -- Removed RegexField.error_message per deprecation timeline.

[Tim Graham <timograham@…>]

In afcf44c:

Refs #23151 -- Removed RegexField's unused error_message parameter.

Should have been removed in b6ea1961eb6816dee4370fb0ebd49dba29478db1.

[Tim Graham <timograham@…>]

In d53fc761:

[1.11.x] Refs #23151 -- Removed RegexField's unused error_message parameter.

Should have been removed in b6ea1961eb6816dee4370fb0ebd49dba29478db1.

Backport of afcf44c10108141e66a8aef0a3cbc151b1c16855 from master