Think I’m getting the same problem.
I have the following line in my Fastlane file which fails.
BUILD_NUMBER = sh("expr $(git rev-list origin/${BITRISE_GIT_BRANCH} --count) - $(git rev-list HEAD..origin/${BITRISE_GIT_BRANCH} --count)").chop
but, if I hard coded the parameter to the following, it works (???)
BUILD_NUMBER = sh("expr $(git rev-list origin/release/2.0.1 --count) - $(git rev-list HEAD..origin/release/2.0.1 --count)").chop