Re: how to track down "invalid face attribute" errors?

[Robert Pluim]

>>>>> On Wed, 05 Oct 2022 14:32:04 +0200, Felix Dietrich 
>>>>> <felix.dietrich@sperrhaken.name> said:

    Felix> But “xfaces.c:merge_face_ref” (which produces the error message) has 
a
    Felix> “struct window w” parameter.  I believe in cases where it is not 
NULL,
    Felix> which it isnʼt when running the above code, this could be used to 
derive
    Felix> the buffer and the bufferʼs position using the struct members 
“contents”
    Felix> and “pointm’: 1. “contents” stores, for leaf windows, the windows
    Felix> buffer; its descriptions mentions other possible value types it may 
hold
    Felix> [1]; I do not know in how far these other types have to be considered
    Felix> here.  2. “pointm” refers to a marker holding the current buffer
    Felix> position in window; its description states that it is “used only when
    Felix> the window is not selected”.  Therefore, it is possible that, if the
    Felix> window “w” is the selected one, the point would have to be taken from
    Felix> another source (perhaps the “PT” macro in “buffer.h”).

Weʼre not necessarily examining the faces of the character at (point),
weʼre going through redisplay of the buffer, I thought?

    Felix> Also note that, if the position would be added to the log entry,
    Felix> multiple log entries would not be merged anymore.  Additionally, with
    Felix> the code above, the position is actually after the text (at
    Felix> ‘point-max’); therefore, this might not be useful information to add.

    Felix> I am not sure if the whole thing is worth the effort or would 
complicate
    Felix> the creation of a simple log entry for a, hopefully, rare case to 
much.

Itʼs more effort than Iʼm willing to go to, at least :-)

    Felix> Anyway, perhaps, if there is any interest in adding information to 
the
    Felix> “Invalid face attribute” log message, further discussion should move 
to
    Felix> a wishlist bug report?

Yes. That will get it in front of people who know the relevant code
better than I do.

Robert
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