grade upload silently rejects valid HTML

[samuelgruetter]

I used the grade upload function to upload reviews like

It looks like you understood conceptually how to construct a bad program, but what you wrote down in Coq is not what you meant. I think the confusion comes from the fact that the semicolon can have two meanings: It can separate list elements, but it's also used in the notation for (Bind c f), which is printed as "x <- c; f x".<br/>
If you write<br/>
<br/>
Example bad: prog :=<br/>
  [Lock 1 ; Lock 2] ++ [Lock 2 ; Lock 1].<br/>
<br/>
you get a program consisting of 4 threads. What you meant is<br/>
<br/>
Example bad: prog := [(_ <- Lock 1; Lock 2); (_ <- Lock 2; Lock 1)].<br/>
<br/>
If you think your difficulties were related to understanding "Bind", please ask about it in the office hours!

This is valid HTML according to https://validator.w3.org/check, but when I checked the display on the website, it says HTML error: Unknown HTML tag -.

I suspect it's related to the semicolon, but apparently a semicolon inside quotes does not cause a problem.

The fix for this instance was easy: Just manually edit using the website.

But there are two problems to fix:

• If you upload HTML which the website doesn't consider valid, it should show an error during the upload.
• It should accept all valid HTML.

[achlipala]

Task accepted to raise a proper error on invalid HTML (though I might very well save that task for a future semester).

FWIW, the HTML error in your example is the < characters, which should be <s.