Merge pull request #16263 from jawshooah/travis-brew-install

Travis: add helpers for brew install and upgrade

ci/travis/helpers.sh

@@ -29,6 +29,24 @@ header () {
   echo
 }
 
+brew_install () {
+  local pkg=$1
+  # if pkg is already installed, upgrade it
+  if brew list -1 | grep -q "^${pkg}\$"; then
+    brew_upgrade "$pkg"
+  else
+    run brew install "$pkg"
+  fi
+}
+
+brew_upgrade () {
+  local pkg=$1
+  if ! brew outdated "$pkg"; then
+    # allow upgrade to fail since we don't strictly need it
+    run brew upgrade "$pkg" || true
+  fi
+}
+
 # disallow unbound variables during build step
 enter_build_step () {
   set -o nounset

ci/travis/install.sh

@@ -13,8 +13,8 @@ enter_build_step
 header 'Running install.sh...'
 
 # install Formulae and Casks without which some tests would be skipped
-run brew install cabextract
-run brew install unar
+brew_install cabextract
+brew_install unar
 run brew cask install Casks/adobe-air.rb
 
 # install bundler and project dependencies in $GEM_HOME