[Discussion] Conflict between pr-review and magit-diff-refine-hunk

[gavv]

Hi,

I'm using magit-diff-refine-hunk set to all, which highlights changed/removed words inside of diff lines.

When this option is used inside pr-review buffer, and when there is a comment inside an area highlighted by the refined hunk mode, a fontification bug can happen.

Normally my in-diff blocks are rendering like this:

But if such block overlaps with refined highlighting, it looks like this:

Here, "PENDING COMMENT" and "Test comment" should have blue background, but they are green instead.

(Screenshots are taken from my fork in #11, but I think it doesn't matter in this case, see below.)

This happens because pr-review applies fontification using text properties, and refined highlighting is done using overlays, which take precedence over properties:

Text content at position 175792:


There is an overlay here:
 From 175585 to 176028
  diff-mode            fine
  evaporate            t
  face                 diff-refine-added


There are text properties here:
  face                 pr-review-in-diff-pending-begin-face
  font-lock-face       magit-diff-context
  pr-review-pending-review-thread [Show]

Here, diff-refine-added is applied to a wider area (the whole comment block is inside that area), and takes priority over pr-review-in-diff-pending-begin-face. Hence background becomes green instead of blue.

One solution is to teach pr-review to use overlays instead of text properties. This way it can control priorities precisely.

I think this approach makes sense - pr-review works "on top" of magit sections, and inserts its own blocks inside them. Hence it would be logical if pr-review fontification would also work "on top" of original magit fontification - which AFAIK can be achieved only using overlays.

Let me know what do you think about this approach. If you think it makes sense I can try to prepare a patch that uses overlays instead of text properties.