Re: [TCLCORE] [Tcl-bugs] [Tk] (jan.nijtmans) com (revised_text): Is this assert correct? And we are (for now) only interested in --disable-aqua builds

[Francois V. <fvo...@fr...>]

Le 06/09/2024 à 22:15, Francois Vogel a écrit :
>
> However the assert triggers on macOS when configuring Tk with 
> --enable-symbols=mem --disable-aqua and running textIndex.test _under 
> xvfb_.
>
Some news:

- This is not always reproducible. Sometimes the assert triggers 
sometimes not. But it's easy to get (happens ~50% of the runs).

- When the assert triggers during textIndex-19.12.2, string values of 
indexPtr1 and indexPtr2 in TkTextIndexCountBytes() are 3.40 and 3.39 
respectively. This is indeed not supposed to happen (one should have 
TkTextIndexCompare(indexPtr1, indexPtr2) <= 0, i.e. ordered indices).

- The call to TkTextIndexCountBytes() that leads to the assert 
triggering is in TkrTextIndexForwBytes() (tkTextIndex.c:3085). This line 
reads:

    assert(!rc || (int) TkTextIndexCountBytes(&index, dstPtr) == byteCount);

- At this point, the string values are index = 3.40 and dstPtr = 3.39. 
dstPtr is computed the line just before by:

     rc = TkBTreeMoveForward(dstPtr, byteCount);

At this point, byteCount is...  -1 !!

This is not supposed to happen. Never. Because the case byteCount < 0 is 
ruled out a bit before in that same function TkrTextIndexForwBytes() as 
follows:

     if (byteCount < 0) {
         TkrTextIndexBackBytes(textPtr, srcPtr, -byteCount, dstPtr);
         return 0;
     }

This is very mysterious to me. Any idea?

Regards,

Francois