Glyphs with multiple unicode values loss them

[khaledhosny]

UFO glyphs with multiple unicode values will result in a warning like:

Multiple unicode values for glyph space: 32, 160

and the glyph in the generated instance will have no Unicode values at all, breaking the font.

Multiple unicode values are supported in UFO and shouldn’t cause a warning. I check the code and it seems that there are multiple places that assume there is always one unicode value per glyph.

[LettError]

Sorry I was distracted and missed this issue. It looks like this needs to be fixed. The rationale for the current code, mutator tries to establish the right unicode value for a glyph by looking at all the masters. These might vary and the solution was to warn and hope for an external fix. I'll review your changes.

[LettError]

What if:

• glyph.unicodes becomes the superset of all unique unicode values in all masters
• glyph.unicode will be the unicode value from the neutral glyph
• report clashes, absences

In practice there seem to be few occasions of actual clashes, but sometimes there are masters with the occasional value missing. Making a superset is more forgiving for situations with some missing values.

• for glyphs with multiple unicode values, does the order matter?
• if the neutral glyph has no unicode, but other masters do, it could pick the first available value from glyph.unicodes if there are any.

[khaledhosny]

The order is not important, they will end up as multiple entries in the cmap table. One way to keep backward compatibility is to do something similar to defcon; keep unicode that is a shorthand for the first entry in the unicodes list.