Update: It looks like this issue has now been fixed in MacOS 10.12.2 (Darwin 16.3.0). Thanks to 'Kumazatheef' for the update.
I recently upgraded one of our Mac Mini build servers to macOS Sierra. This was needed in order to build for iOS 10 and Xcode 8. Well I could have held back on previous OSX version for a while, but with Apple it is an inevitable upgrade tide you are swimming against!
The upgrade went well, however something broke when trying to get our Jenkins server (FreeBSD) to build our iOS app on the Mac Mini as a build slave.
At the start of our build script we need to set the keychain path (our iOS keys are in their own keychain to keep things nice and clean) and unlock the keychain so that the keys and certs for signing the apps can be found by Fastlane:
Now, this isn’t an issue when the Jenkins process itself runs as that uses a ssh key to login so it doesn’t need to ask for a password interactively. But as I was trying to debug the first issue (the extension change of keychain files) it cause me to chase a red herring for quite a while.
I’ve still no idea what is causing this or why logging in via a password means that running the security command doesn’t work as intended. And, no, there is no credential forwarding enabled or anything like that. My guess is that there is something set in the environment, but I’ve yet to track it down.