On 04/02/2019 12:26, Nikolay Nikolov wrote:
On 2/3/19 11:22 PM, C Western wrote:
I suspect the new sorting routines need some work - lazarus compiled
with the latest trunk hangs on start up, and it looks like an
infinite loop in sorting. Stack trace below.
Even though the sort routine did slightly change, I believe this
exposes a bug in lazarus. The CompareBinary routine in
syneditmarkuphighall.pp returns -1 when the strings are equal, while
it should return 0 in this case. This is like having two elements in
the array, for which (a<b) and (b<a) are both true at the same time.
The Compare function, passed to the sort algorithms must satisfy the
mathematical properties of comparisons, otherwise the result is
undefined (whether it should results in a hang (like in this case), or
in a bad sort (like in the previous variation of the algorithm) is a
separate discussion).
The attached patch fixes this.
I am happy to confirm lazarus starts with the patch applied.
Many thanks
Colin
_______________________________________________
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
