div id="preamble" dropped from reader mode for article on plato.stanford.edu

[kbrosnan]

Site with issue and any steps to reproduce

https://plato.stanford.edu/entries/qt-quantcomp/

Reader mode doesn't load, the first part of entries with longer introductions.

*Edit: I also can reproduce this on Firefox-Desktop

Expected behavior

Reader mode renders the introductory part successfully

Actual behavior

Reader mode fails to render the introductory part

Does toggling Tracking Protection fix the issue? (Press the shield icon in the toolbar while on the site to see toggle)

No

Can you reproduce in Chrome (or other non-Mozilla browser)?

No

Device information

• Android device: All
• Fenix version: All

[gijsk]

I wonder if #646 fixed this so that we pull in both the ToC and the preamble siblings of the main content. I'll try and double-check in the near future. Leaving this un-tagged until I've done that.

[gijsk]

Looks like the issue here is that we score the <div id="main-text"> very highly (lots of content) and then the preamble is too far away in the DOM tree and too small to convince the algorithm to join the two up.

I'm not 100% sure how to fix this in a systematic fashion.

[rien333]

The bibliography is also always missing on this site. Seems to be the same cause; it's a div right after <div id="main-text">. Note, however, that both the preamble and the bibliography are embedded in <div id="article"> and <div id="article-content"> tags. I know nothing about the algorithm, but those may be useful.