From time to time we have pupil interns. Our last intern, let’s call him John started some Xcode Swift programming and all was fun and great. After more than a week of successful programming small pieces of this and that he created a png picture file using the gimp editor. He then pulled the file into the project and from that minute on, Xcode did not want to compile any more.
It turned out, that the problem was the copypng perl script used by Xcode (found here: Programme ▸ Xcode.app ▸ Contents ▸ Developer ▸ Platforms ▸ iPhoneOS.platform ▸ Developer ▸ usr ▸ bin). Since the intern had created a subdirectory called John`s programs, he had a directory name with not only a space, but also a capital letter and a quote in it (I can not guarantee the particular type of quote any more, but I think it was the one I used above).
When I think back of the times where just on of the three was forbidden or problematic, I still shiver and I have to admit, that I am still a little bit superstitious regarding the use of blanks in directory names, even nowadays.
It turned out, that while compiling the swift files with that quote char in the file name did work, it did not work for the copypng perl script.
We changed the directory name and all went well a second later.