Github Actions: xcodebuild fails due to server fingerprint

Question

I am trying to build a macOS app with Github Actions. This already worked very well, until I migrated my dependencies to Swift Package Manager. Now I am getting the following error while building my app:

xcodebuild: error: Could not resolve package dependencies: The server SSH fingerprint failed to verify.

I have a private GitHub repository as a dependeny in my application added as a Swift Package using a ssh location. Therefore I need to add my ssh key for the dependency in the Set up ssh-agent step. Manually cloning the repository in a step using git clone is working fine but I need to get it work with xcodebuild in order to successfully build my app.

Workflow file

name: Main
on:
  push:
    tags:
      - 'v*.*.*'

jobs:
  build:
    name: Release
    runs-on: macOS-latest
    steps:
      - name: Checkout
        uses: actions/checkout@master
        with:
          fetch-depth: 1
      - name: Set up ssh-agent
        uses: yakuhzi/action-ssh-agent@v1
        with:
          public: ${{ secrets.SSH_PUBLIC_KEY }}
          private: ${{ secrets.SSH_PRIVATE_KEY }}
      - name: Build application
        run: |
          sudo xcode-select -switch /Applications/Xcode_11.app
          xcodebuild -project Application.xcodeproj -scheme Application -configuration Release -derivedDataPath $HOME/Application build

Answer 1

Finally I figured it out. It seems like its a known issue in Xcode 11 (https://developer.apple.com/documentation/xcode_release_notes/xcode_11_release_notes).

Thanks to Dosium in this post (https://discuss.bitrise.io/t/xcode-11-resolving-packages-fails-with-ssh-fingerprint/10388), I was able to get it work.

The solution is to run the following command before running xcodebuild: for ip in $(dig @8.8.8.8 github.com +short); do ssh-keyscan github.com,$ip; ssh-keyscan $ip; done 2>/dev/null >> ~/.ssh/known_hosts

Answer 2

For CircleCI:

Adding onto Yakuhzi's answer, here's what the step looks like in Circle Ci's yaml file:

- run:
    name: Enable SSH
    command: |
       for ip in $(dig @8.8.8.8 github.com +short); do ssh-keyscan github.com,$ip; ssh-keyscan $ip; done 2>/dev/null >> ~/.ssh/known_hosts