This seems like a nice improvement, though I worry that it sets up an expectation that a client may not honour.

• Bug 52028 has been marked as a duplicate of this bug. ***

From Bug 52028:
TemplateData should allow some parameters to have default values which are
prefilled when using the VisualEditor transclusion manager.

An example would be the current date for accessdate in citation templates.

I almost submitted a new bug, but saw this one in the "possible duplicates" at the last second... Pasting the text I wrote, in case it helps:

Most cleanup templates, banner and inline, have a "|date={{CURRENTMONTHNAME}} {{CURRENTYEAR}}" parameter.

If we don't add them, then (on En.Wiki) AnomieBot adds them a few minutes later*, which clutters the history, and more importantly Buries the initial edit in watchlists, making it harder for us humans to check.

*eg. https://en.wikipedia.org/w/index.php?title=Red_squirrel&curid=638291&diff=572563931&oldid=572553559

Could we have an "Add current month and year" button, for parameters like this?

Or, a tweak for TemplateData so that specific templates will add this parameter/value by default?

This is generally worked around by wikis by providing another template that when substituted inserts the autofill parameters.

e.g.

{{subst:newdelete|reason=Foo}}
->
{{delete|reason=Foo|date=YYYY-MM-DD}}

These templates need a "must-subst" property of sorts in template data first (bug 65550), but that would make this easier already.

The subst-behaviour is a super set of the scope of this bug (autofill values), however it may be enough.

The problem with a declarative autofill (as opposed to substituting a wrapper template) is that you'd need a fair amount of logic to express what you want to be filled in. Obviously you don't just want a literal string to be inserted, because then you'd just have users omit it and use that value as the default value.

With autofill you most probably want a dynamic value (e.g. the result of invoking a template, or magic words like current date/times, current revision user, base page name etc. Some of these (like date) could be trivially done, but that still leaves a lot of questions (how to specify the date etc.) and compatibility.

So I'd say let's solve bug 65550 first and see how that unfolds. If we still feel a need for this we can revisit it later.

This should additionally be helpful since subst-ing is that wikis do now without VisualEditor so they likely have that in place already and will want to keep that for wikitext users.

Change 157820 had a related patch set uploaded by Jforrester:
Implement new 'autovalue' parameter property

https://gerrit.wikimedia.org/r/157820

Change 157820 merged by jenkins-bot:
Implement new 'autovalue' parameter property

https://gerrit.wikimedia.org/r/157820