[Python-modules-team] Bug#690942: python-pgmagick: Image.attribute does not set the attribute but instead appends to it

[Juraj Komačka]

According to 
http://www.graphicsmagick.org/api/attribute.html#setimageattribute 
special handling for EXIF:Orientation has been introduced in 
http://hg.code.sf.net/p/graphicsmagick/code/rev/90be78bb60fb

 > The new EXIF:Orientation attribute replaces the existing value rather 
than being concatenated to it as when setting other attributes.

I have reproduced exactly same behaviour for GM core C API with current 
stable from upstream, the problem is resolved in latest developments 
snapshot from (1.4-020170315). AFAIK no additional change is needed in 
python-pgmagick or libgraphicsmagick++.