Comment excerpts in activity feeds previously used either the first 200
display characters of a comment or, for review comments, its first
physical line. That excerpt is rendered as Markdown in the feed, so if
the excerpt began with a leading blank lines or structural markdown
syntax, the excerpt would render as empty or produce broken output. For
example, a review comment beginning with a code fence stored only the
opening fence, which rendered as an empty code block.
This commit instead renders feed excerpts as prose only, dropping code,
math, tables, images and HTML, which also fixes already stored excerpts.
New excerpts start at the first prose line, and review comments get the
same excerpt as issue comments.
This produces meaningful excerpts in more cases while preserving their
original Markdown.
---
For a comment that contains the following:
````
```
some code
```
hello
````
This previously rendered as:
<img width="816" height="118" alt="Screenshot 2026-09-08 at 5 06 47 PM"
src="https://github.com/user-attachments/assets/9d125363-72de-46bf-b47a-961245a79c5f"
/>
And now renders as:
<img width="807" height="89" alt="Screenshot 2026-09-08 at 5 08 30 PM"
src="https://github.com/user-attachments/assets/d2dcdc6d-d7a9-437f-8e9c-b845fe99fa5e"
/>
---------
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: bircni <bircni@icloud.com>
This PR removes (almost) all path tricks, and introduces "renderhelper"
package.
Now we can clearly see the rendering behaviors for comment/file/wiki,
more details are in "renderhelper" tests.
Fix#31411 , fix#18592, fix#25632 and maybe more problems. (ps: fix
#32608 by the way)
Remove unmaintainable sanitizer rules. No need to add special "class"
regexp rules anymore, use RenderInternal.SafeAttr instead, more details
(and examples) are in the tests
