Today I created a new file at ./Resources/Environment.xcconfig, but git didn't
pick up on the file and didn't show it in git status. I suspected the file was
gitignored, but nothing in my .gitignore was obviously excluding this file.
git status --ignored adds a section in to the normal status output that lists
all the ignored files. My file was in it, but I still didn't know why.
git check-ignore as a bare command confirms the ignored status of the passed
in file, but adding the -v flag indicates the source of the ignore. I ran
git check-ignore -v Resources/Environment.xcconfig and the exact line number
in gitignore showed what caused the file to be ignored.
In my case, a different Environment.xcconfig existed before and had been removed from the repo, but not from gitignore so it caused the new file to be ignored as well.