bug#33567: Syntactic fontification of diff hunks

[Dmitry Gutov]

On 19.12.2018 2:11, Juri Linkov wrote:

> Does it help to remove foreground colors from diff-added and diff-removed?

Yup. Except if I customize those and restart, I think the +'s and -'s on 
the left will become black as well, which is somewhat of a loss. So the 
colors might need to be moved to other definitions, e.g. 
diff-indicator-added.

Further, I'm not sure if we should do the same to the look of the 
diff-mode buffers when diff-font-lock-syntax is nil. Just something to 
consider.

Third, third-party code might rely on those faces looking as they do 
now. E.g. in diff-hl, diff-hl-insert inherits from diff-added, although 
this package likely won't be affected by this change (the faces define 
their own :foreground, for reasons lost to history).

> Neither GitHub nor GitLab have foreground green/red colors, only background
> green/red colors.

Those are the interfaces that built up my expectations as well.