Plantuml not rendering in Readme only in Issues and Wiki

[lukaskwkw]

Gitea Version

1.16.4

Git Version

2.30.2

Operating System

Windows 11

How are you running Gitea?

Docker image

Database

PostgreSQL

Can you reproduce the bug on the Gitea demo site?

No

Log Gist

No response

Description

PlantUML rendering is only working in Issues & Wiki. Not in README.md files.

I.e. using code in README.md

```plantuml
@startuml
Bob -> Alice : hello
@enduml
```

will generate <code> block with language-plantuml class but won't render any content in if body

{{if .RequireHighlightJS}}
nothing here
{{end}}

I was able to workaround this by adding PageIsViewCode condition into if statement from docs example:
https://docs.gitea.io/en-us/customizing-gitea/#example-plantuml

{{if or .PageIsViewCode .RequireHighlightJS}}

It might be similar to #12307

Screenshots

with single RequireHighlightJS condition

with addtional PageIsViewCode condition

[silverwind]

We should probably remove RequireHighlightJS and instead suggest to always just call parsePlantumlCodeBlocks. We're not even using higlight.js anymore.

[zeripath]

We should probably remove RequireHighlightJS and instead suggest to always just call parsePlantumlCodeBlocks. We're not even using higlight.js anymore.

Yeah I suspect we should just drop the RequireHighlightJS things from our templates.

@lukaskwkw you should be fine to just remove the requirement on the RequireHighlightJS from your pages - an alternative option might be to also detect IsMarkup in addition to RequireHightlightJs and perhaps we should migrate all places that use RequireHighlightJS to IsMarkup instead.

[lunny]

Looks like RequireHighlightJS could be removed, no standard template use that now.

[lunny]

IsMarkup is still not accurate. We need to detect all markdown sections which has plantuml code blocks.

[silverwind]

I think JS should just execute document.querySelectorAll('language-plantuml') only, no need to hand-hold it via template variables. Scripts will need to lazy-loaded by JS that way.

[zeripath]

@silverwind do you want to propose a documentation update PR?

[silverwind]

Yes, once I figure out something that works.