If present, move config/postcss.config.js to root

This is where the tailwind upgrade tool expects it to be, because
that's the convention, apparently.

Author: flavorjones

lib/install/upgrade_tailwindcss.rb

@@ -1,28 +1,34 @@
 TAILWIND_CONFIG_PATH = Rails.root.join("config/tailwind.config.js")
 APPLICATION_LAYOUT_PATH = Rails.root.join("app/views/layouts/application.html.erb")
+POSTCSS_CONFIG_PATH = Rails.root.join("config/postcss.config.js")
 
-if TAILWIND_CONFIG_PATH.exist?
-  if File.read(TAILWIND_CONFIG_PATH).match?(/defaultTheme/)
-    say "Removing references to 'defaultTheme' from #{TAILWIND_CONFIG_PATH}"
-    gsub_file TAILWIND_CONFIG_PATH.to_s, /^(.*defaultTheme)/, "// \\1"
-  end
+unless TAILWIND_CONFIG_PATH.exist?
+  say "Default tailwind.config.js is missing!", :red
+  abort
+end
 
-  if system("npx --version")
-    say "Running the upstream Tailwind CSS upgrader"
-    command = Shellwords.join(["npx", "@tailwindcss/upgrade@next", "--force", "--config", TAILWIND_CONFIG_PATH.to_s])
-    success = run(command, abort_on_failure: false)
-    unless success
-      say "The upgrade tool failed!", :red
-      say %(        You probably need to update your configuration. Please read the error messages,)
-      say %(        and check the Tailwind CSS upgrade guide at https://tailwindcss.com/docs/upgrade-guide.)
-      abort
-    end
-  else
-    say "Could not run the Tailwind upgrade tool. Please see https://tailwindcss.com/docs/upgrade-guide for manual instructions.", :red
+if File.read(TAILWIND_CONFIG_PATH).match?(/defaultTheme/)
+  say "Removing references to 'defaultTheme' from #{TAILWIND_CONFIG_PATH}"
+  gsub_file TAILWIND_CONFIG_PATH.to_s, /^(.*defaultTheme)/, "// \\1"
+end
+
+if POSTCSS_CONFIG_PATH.exist?
+  say "Moving PostCSS configuration to application root directory"
+  FileUtils.mv(POSTCSS_CONFIG_PATH, Rails.root, verbose: true) || abort
+end
+
+if system("npx --version")
+  say "Running the upstream Tailwind CSS upgrader"
+  command = Shellwords.join(["npx", "@tailwindcss/upgrade@next", "--force", "--config", TAILWIND_CONFIG_PATH.to_s])
+  success = run(command, abort_on_failure: false)
+  unless success
+    say "The upgrade tool failed!", :red
+    say %(        You probably need to update your configuration. Please read the error messages,)
+    say %(        and check the Tailwind CSS upgrade guide at https://tailwindcss.com/docs/upgrade-guide.)
     abort
   end
 else
-  say "Default tailwind.config.js is missing!", :red
+  say "Could not run the Tailwind upgrade tool. Please see https://tailwindcss.com/docs/upgrade-guide for manual instructions.", :red
   abort
 end
 

test/integration/user_upgrade_test.sh

@@ -57,6 +57,15 @@ bundle install --prefer-local
 bundle show --paths
 bundle binstubs --all
 
+# create a postcss file
+cat <<EOF > config/postcss.config.js
+module.exports = {
+  plugins: {
+    autoprefixer: {},
+  },
+}
+EOF
+
 bin/rails tailwindcss:upgrade
 
 # TEST: removal of inter-font CSS
@@ -65,6 +74,12 @@ if grep -q inter-font app/views/layouts/application.html.erb ; then
   exit 1
 fi
 
+# TEST: moving the postcss file
+if [ ! -f postcss.config.js ] ; then
+  echo "FAIL: postcss.config.js not moved"
+  exit 1
+fi
+
 # generate CSS
 bin/rails tailwindcss:build[verbose]
 grep -q "py-2" app/assets/builds/tailwind.css