gegl:shear can lead to segfaults when built with clang
Submitted by Massimo
Link to original bug (#760827)
Description
This becomes a problem because during make, gegl-tester is run with default values and at least when building with CC=clang it seg faults:
/bin/sh: line 6: 16779 Segmentation fault GEGL_SWAP=RAM GEGL_PATH=../operations ../bin/gegl-tester --all -o images/examples -d ... Makefile:775: recipe for target 'examples' failed make[2]: *** [examples] Error 139
See:
https://git.gnome.org/browse/gegl/tree/operations/transform/shear.c#n25
the matrix
1 1 0 1 1 0 0 0 1
is singular and not invertible, affine_transform tries to invert it, it results in nans that then fail every comparison and samplers are given invalid pointers...
BTW setting both x and y gegl:shear properties != 0 does not result in a pure shear transform. For example x=1 and y=-1 would be a 45° rotation combined with a scale.
Anyway the default has to be changed or a reference composition should be added to this op or this operation should be excluded from the generation of example images
Version: git master