nominating this as Q1 blocker, since this is closely tied to the current BLP practices on english wikipedia, a very visible and sensitive part of our policies.

We've encountered this issue too on a private MediaWiki.
Would be really great to have this supported - this would make the VE more versatile in some use cases!

Thanks!

These tasks *really* shouldn't have been merged, despite being about 'the same' area of code (one is about important functionality half done through on-wiki hacky JavaScript, the other is about modifying a fundamental user pattern in core to work with VisualEditor); un-merging.

A note from @Tpt that this is pretty important for successful ProofreadPage integration.

Thomas's suggestion is that if the article is a 404 (non-extant), we sling the contents of preload parameter's indicated article's Parsoid blob as the initial version of the article, and if that's not balanced wikitext (and so not the desired HTML) "oh well", at least it's better than nothing. Thoughts?

ProofreadPage needs support of the EditFormPreloadText hook instead of editinfo/preload parameters. Tracked by task T138588

VisualEditor having preload support for page creation would be nice. Preload is used in article wizards (e.g. en-wp, ru-wp).

Change 329796 had a related patch set uploaded (by Esanders):
Add editintro to notices

https://gerrit.wikimedia.org/r/329796

Change 329796 merged by jenkins-bot:
Add editintro to notices

https://gerrit.wikimedia.org/r/329796

This would be very useful for the Wikidebate project at Wikiversity.

Change 378343 had a related patch set uploaded (by DLynch; owner: DLynch):
[mediawiki/extensions/VisualEditor@master] Enable preload in VisualEditor

https://gerrit.wikimedia.org/r/378343

That patch is very much the "better than nothing" version James suggested. It pulls the article, substitutes in the parameters, and then if it's in visual mode it runs it through Parsoid. It should be functionally-equivalent for the 2017 wikitext editor, though, since that doesn't rely on always containing valid documents.

Change 378726 had a related patch set uploaded (by DLynch; owner: DLynch):
[mediawiki/extensions/VisualEditor@master] DesktopArticleTarget: Support preloadtitle in source mode

https://gerrit.wikimedia.org/r/378726

Change 378726 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] DesktopArticleTarget: Support preloadtitle in source mode

https://gerrit.wikimedia.org/r/378726

Change 378343 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] Enable preload in VisualEditor

https://gerrit.wikimedia.org/r/378343

Ah, that's because I didn't remove preloadtitle from the unsupportedEditParams list.

Note that if you edit the URL to removes just that parameter, it gets the expected result: https://en.wikipedia.beta.wmflabs.org/w/index.php?title=Template_talk:Submit_an_edit_request&action=edit&preload=Template%3ASubmit_an_edit_request%2Fpreload&editintro=Template%3AEdit_protected%2Feditintro&preloadparams%5B%5D=&preloadparams%5B%5D=Template%3ASubmit_an_edit_request&section=new

Change 379246 had a related patch set uploaded (by DLynch; owner: DLynch):
[mediawiki/extensions/VisualEditor@master] Hooks: remove preloadtitle from unsupported list

https://gerrit.wikimedia.org/r/379246

Change 379246 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] Hooks: remove preloadtitle from unsupported list

https://gerrit.wikimedia.org/r/379246

Just to confirm, now that patch has made its way to the beta cluster, the inputbox button works and gets us this:

Adding the tag per https://www.mediawiki.org/w/index.php?title=Topic:Tys3st4u4fbxis43 .

Change 380530 had a related patch set uploaded (by DLynch; owner: DLynch):
[mediawiki/extensions/VisualEditor@master] Api: include preload content when section=new

https://gerrit.wikimedia.org/r/380530

Change 380530 merged by jenkins-bot:
[mediawiki/extensions/VisualEditor@master] Api: include preload content when section=new

https://gerrit.wikimedia.org/r/380530