When matching tags, Robot supports Boolean operators AND, OR and NOT. These operators are case-sensitive, but they are currently searched anywhere from a tag pattern so something like FORCE is interpreted as F OR CE. The general recommendation has been using lower case names like force in tag patterns, but not everyone knows this. This behavior most often causes issues with command line options like --include, but #5579 demonstrates that also the -tag syntax in the data is affected.

Handling tags like FORCE, HAND, PORT, KNOT as Boolean expressions makes no real sense, and we have decided to change pattern matching so that all these are considered literal patterns. Boolean operators will still be supported, but they either need to be surrounded by spaces like X OR Y or tag names need to be lower case like xORy. The latter format is mostly supported for backwards compatibility reasons, but it also allows using patterns on the command line without quoting like --include xORy.

This change is backwards incompatible and we don't want to do it in a feature release like RF 7.5. The change is considered rather important and backwards compatibility issues aren't considered too severe, though, so changing the behavior in a major release like RF 8.0 ought to be fine. Delaying the change a little also makes it possible to properly deprecate the XORY format in RF 7.5.