Subject: Re: bug#1176: redisplay bugs

From: Glenn Morris <[email-masked]>
Date: Mon, 20 Oct 2008 22:48:11 -0400

I found all this rather hard to understand. "I expected to see", "I
actually saw", never mind separate bugs, would have made it a lot
easier.

> 1. Faces on a display property on a before-string behave differently
>    depending on where the display property is in the before-string.
>    For a display property at the beginning of the before-string, its
>    face is used and the before-string's face is ignored (I think this
>    is correct).  For a display property not at the beginning of the
>    before-string, its face is completely ignored, and the face of the
>    before-string is used instead.

Appears to be fixed in 22.2 and up.

I base this on the strike-through face appearing on the whole
before-string in 22.2, but only on the first two chars in 22.1.

And on the background of only the first two characters being white in
22.1 (the rest being yellow), but all being white in 22.2

> 2. When a substring of a before-string beginning at offset O has a
>    display property which is a string S, the first O characters of S
>    are not displayed.  If S is not at least O+1 characters long, then
>    disastrous things start to happen.  This is clearly a bug.

Appears to be fixed in 22.2 and up.

I base this on seeing only one "|" before VWXYZ in 22.1, but two in 22.2.

> 3. The before-string somehow inherits face attributes from the face
> of the character that follows the start of the overlay.

Appears to be fixed in 22.2 and up.

I base this on seeing underlining and a yellow background on "VWXYZ"
in 22.1, but not 22.2.

> 4. The display property of an overlay somehow inherits face
> attributes from the face of the character that follows the start of
> the overlay.

I think this one still applies. The "]" in the example has a yellow
background.

> 5. The help-echo and mouse-face properties of an overlay with both a
> before-string and a display property only affect the material
> displayed by the overlay's display property.

This appears to still be the case. Only the "]" in the example has
mouse-face and help-echo.