macos-14 runner: intermittent "invalid developer directory" when installing Xcode 16.0

[tsal]

Describe the bug
Our first step is to setup Xcode in our builds. Today we've been getting a large number of immediate failures, in the Xcode setup step; error message is xcode-select: error: invalid developer directory '/Applications/Xcode_16.0.app'. This normally indicates the directory is not a signed app or package folder from Apple, or it's just outright missing.

To Reproduce
Steps to reproduce the behavior:
Currently, the there is no reliable reproduction, but try installing 16.0 on a macos-14 runner a few times and you should see the error occasionally (we see it 1 in 6 right now).

Expected behavior
Since Xcode 16.0 is not the latest version, but compatible with macos-14, I would expect it to install without issue.

Runner Version and Platform

macos-14

OS of the machine running the runner? macos

What's not working?

We inject the version via secret, hence the ***, but here's the output:

Job Log Output

N/A, the job doesn't get past this first step.

Runner and Worker's Diagnostic Logs

Don't have access to a _diag folder that I can find in the log capture ZIP.

[ivard]

We sometimes experience the same issue indeed. In most cases the issue doesn't occur, but sometimes we get xcode-select: error: invalid developer directory '/Applications/Xcode_16.0.app/Contents/Developer'. Maybe there is a rolling upgrade going of the MacOS 14 runner image that breaks things.