Desktop: Export of mermaid render no longer works on 2.6.4+

[graphit0]

PDF and HTML File export of mermaid renders stopped working on 2.6.9 and shows up as plain code

Environment

Joplin version: 2.6.9
First appears at 2.6.4: 2.6.2 is unaffected
wonder if commit 98ed2be might have something to do with it
Platform: prod, win32; prod, linux is untested
OS specifics: Tested on Windows 7, reported on Mac OS 12.0.1 as well

Steps to reproduce

1. Create a note
2. paste mermaid graph

flowchart TD
a --- b

Loading

3. Export the note as PDF or HTML File
4. Open the note and see unrendered mermaid code

Describe what you expected to happen

The rendered graph to be present in exported document

Notes

• PlantUML, katex, tables, checkboxes, etc are unaffected
• Mermaid graphs render fine in the Joplin view mode
• HTML Directory export seems to be unaffected

Logfile

Export HTML result:  
{warnings: Array(0)}
warnings: []
[[Prototype]]: Object
constructor: ƒ Object()
hasOwnProperty: ƒ hasOwnProperty()
isPrototypeOf: ƒ isPrototypeOf()
propertyIsEnumerable: ƒ propertyIsEnumerable()
toLocaleString: ƒ toLocaleString()
toString: ƒ toString()
valueOf: ƒ valueOf()
__defineGetter__: ƒ __defineGetter__()
__defineSetter__: ƒ __defineSetter__()
__lookupGetter__: ƒ __lookupGetter__()
__lookupSetter__: ƒ __lookupSetter__()
__proto__: (...)
get __proto__: ƒ __proto__()
set __proto__: ƒ __proto__()

[tessus]

To also put my findings here:

I have reverted both Mermaid commits (06e427f and c499473) for testing and it still does not work, so it has nothing to do with these 2 commits.

Unfortunately I don't know what the culprit is, but at least I could eliminate my 2 commits related to Mermaid.

[Daeraxa]

Results of me playing around:

It is broken in the same commit as the other issue, the html pack commit 98ed2be

Did some more playing and got rid of just the last function and got the graph back, so it is something in there or something that it calls upon. (commented out the whole last public async close() function and change it to just async close() {})

Played a bit more and changed this line

joplin/packages/lib/services/interop/InteropService_Exporter_Html.ts

Line 35 in 41cb47b

this.packIntoSingleFile_ = 'packIntoSingleFile' in options ? options.packIntoSingleFile : true;

to false and it works again - because it then bypasses the extra code in that function I mentioned before.
this.packIntoSingleFile_ = 'packIntoSingleFile' in options ? options.packIntoSingleFile : false;

Is there a reason why exporting to PDF needs to go via the additional code added for the HTML single file packing? The change notes imply this should only fire for exporting as a single HTML.

[tessus]

Is there a reason why exporting to PDF needs to go via the additional code added for the HTML single file packing?

Not that I can think of, but I didn't make that change. I remember a few issues we had a while back with toc not working when certain unicode characters were used in headings. But it had nothing to do with single file packing.

[laurent22]

Hmm, yes if it can't be fixed in htmlpack we can probably just bypass it for PDF export. It's indeed not necessary in this case.

[yiyinyiyang]

In the 2.5.12 version of the test, working fine, but in the latest 2.6.9 version, when exporting PDF and html mermaid render effect will not work.