(Re)Introduce the ajax_load theme parameter and skip diazo theming, if set.

[thet]

Related:
plone/Products.CMFPlone#4188
plone/Products.CMFPlone#4169
plone/plone.base#85
#404
plone/plone.app.portlets#203

[mister-roboto]

@thet thanks for creating this Pull Request and helping to improve Plone!

TL;DR: Finish pushing changes, pass all other checks, then paste a comment:

@jenkins-plone-org please run jobs

To ensure that these changes do not break other parts of Plone, the Plone test suite matrix needs to pass, but it takes 30-60 min. Other CI checks are usually much faster and the Plone Jenkins resources are limited, so when done pushing changes and all other checks pass either start all Jenkins PR jobs yourself, or simply add the comment above in this PR to start all the jobs automatically.

Happy hacking!

[thet]

@jenkins-plone-org please run jobs

[petschki]

LGTM. This should also be added to the docs, so that theme integrators can implement this in their custom rules.xml and parameters too.

[thet]

@jenkins-plone-org please run jobs

[petschki]

@thet can this be merged today or tomorrow? then I could do a release and @mauritsvanrees could include it in the upcoming Plone 6.1.2 release.

[thet]

@petschki yes, it can be merged. I just wanted to keep it open until I have done the documentation.

[petschki]

@thet so you merge it, when you're ready with the docs right? I do not have the complete overview what needs to be merged together with this PR ...

[thet]

@petschki I've done the docs - improving them is another story and separate from this PR.

plone/documentation#1961

I'll merge.

[davisagli]

This doesn't seem safe to me. If I have Diazo rules which change the markup of part of a page, then I want to get the changed markup whether I'm loading the entire page or replacing part of it via an ajax request.

[mauritsvanrees]

Wouldn't that always be in a custom theme? Then you will have your own variables, rules, and index.html.

Sure, this is something to watch out for if your theme is based on Barceloneta. But at least the fix is easy: in the theme variables set ajax_load = python:True (if I have the spelling correct).

[thet]

@davisagli

Also, this same variable was present in Barceloneta in Plone 5 and fell out by accident (I think) in Plone 6:

Uhm the ajax_load Diazo switch wasn't present in plonetheme.barceloneta, though I was so sure about it I didn't even check before.
Also I was using it ever since in own themes.

Hm.

But I agree with @mauritsvanrees argument. A custom theme will most likely use own rule files, so I do not see a problem here too.

[davisagli]

@thet @mauritsvanrees Right, it helps that this change is only for the Barceloneta theme and not custom themes.