workflows/build-pkg: actually try to install package.

- This should help avoid this regressing
- Remove existing Homebrew installation(s)
- Install it twice to ensure that installing over the top of an existing
  installation works as expected
- Remove existing API cache to ensure we have the freshest files from
  the API in our package

.github/workflows/build-pkg.yml

@@ -3,7 +3,7 @@ on:
   push:
     paths:
       - .github/workflows/build-pkg.yml
-      - package/scripts
+      - package/
   release:
     types:
       - published
@@ -23,6 +23,9 @@ jobs:
       HOMEBREW_NO_ANALYTICS_THIS_RUN: 1
       HOMEBREW_NO_ANALYTICS_MESSAGE_OUTPUT: 1
     steps:
+      - name: Remove existing API cache (to force update)
+        run: rm -rvf ~/Library/Caches/Homebrew/api
+
       - name: Set up Homebrew
         id: set-up-homebrew
         uses: Homebrew/actions/setup-homebrew@master
@@ -101,6 +104,40 @@ jobs:
                           --package-path Homebrew.pkg Homebrew-${{ steps.print-version.outputs.version }}.pkg
                           --sign "${PKG_APPLE_DEVELOPER_TEAM_ID}"
 
+      - name: Remove existing Homebrew installations
+        run: |
+          sudo rm -rf brew /{usr/local,opt/homebrew}/{Cellar,Caskroom,Homebrew/Library/Taps}
+          brew cleanup --prune-prefix
+          sudo rm -rf /usr/local/{bin/brew,Homebrew} /opt/homebrew /home/linuxbrew
+
+      - name: Zero existing installer logs
+        run: echo | sudo tee /var/log/install.log
+
+      - name: Install Homebrew from installer package
+        run: sudo installer -verbose -pkg Homebrew-${{ steps.print-version.outputs.version }}.pkg -target /
+
+      - name: Output installer logs
+        if: ${{ always() }}
+        run: sudo cat /var/log/install.log
+
+      - run: brew config
+
+      - run: brew doctor
+
+      - name: Zero existing installer logs (again)
+        run: echo | sudo tee /var/log/install.log
+
+      - name: Reinstall Homebrew from installer package
+        run: sudo installer -verbose -pkg Homebrew-${{ steps.print-version.outputs.version }}.pkg -target /
+
+      - name: Output installer logs (again)
+        if: ${{ always() }}
+        run: sudo cat /var/log/install.log
+
+      - run: brew config
+
+      - run: brew doctor
+
       - name: Notarize Homebrew installer package
         env:
           PKG_APPLE_ID_USERNAME: ${{ secrets.PKG_APPLE_ID_USERNAME }}

package/scripts/postinstall

@@ -27,18 +27,19 @@ git config --global --add safe.directory "${homebrew_directory}"
 git reset --hard
 git checkout --force master
 git branch | grep -v '\*' | xargs -n 1 git branch --delete --force
-git config --global --unset safe.directory
+git config --global --unset safe.directory "${homebrew_directory}"
 
 # move to /usr/local if on x86_64
 if [[ $(uname -m) == "x86_64" ]]
 then
-  mv -v "${homebrew_directory}" "/usr/local/Homebrew"
+  sudo mkdir -vp /usr/local/bin /usr/local/Homebrew
+  cp -a "${homebrew_directory}"/* "${homebrew_directory}/".??* "/usr/local/Homebrew/"
+
   # create symlink to /usr/local/bin/brew
-  sudo mkdir -vp /usr/local/bin
   ln -svf "../Homebrew/bin/brew" "/usr/local/bin/brew"
 
-  homebrew_directory="/usr/local"
+  homebrew_directory="/usr/local/Homebrew"
-  cd "${homebrew_directory}"
+  cd /usr/local
 fi
 
 # create missing directories
@@ -47,7 +48,7 @@ sudo mkdir -vp Cellar Frameworks etc include lib opt sbin share var/homebrew/lin
 # set permissions
 logged_in_user=$(echo "show State:/Users/ConsoleUser" | scutil | awk '/Name :/ { print $3 }')
 group=$(id -gn "${logged_in_user}")
-if [[ "${homebrew_directory}" == "/usr/local" ]]
+if [[ "${homebrew_directory}" == "/usr/local/Homebrew" ]]
 then
   chown -R "${logged_in_user}:${group}" Cellar Frameworks Homebrew bin etc include lib sbin share var/homebrew/linked
 else