Store existing checkout options but ignore :head pods

lib/cocoapods/installer.rb

@@ -465,8 +465,9 @@ module Pod
     # @return [void]
     #
     def write_lockfiles
-      # checkout_options = sandbox.checkout_options
-      @lockfile = Lockfile.generate(podfile, analysis_result.specifications, sandbox.checkout_sources)
+      external_source_pods = podfile.dependencies.select(&:external_source).map(&:root_name).uniq
+      checkout_options = sandbox.checkout_sources.select { |root_name, _| external_source_pods.include? root_name }
+      @lockfile = Lockfile.generate(podfile, analysis_result.specifications, checkout_options)
 
       UI.message "- Writing Lockfile in #{UI.path config.lockfile_path}" do
         @lockfile.write_to_disk(config.lockfile_path)

lib/cocoapods/installer/analyzer.rb

@@ -53,6 +53,7 @@ module Pod
         @result.podfile_state = generate_podfile_state
         @locked_dependencies  = generate_version_locking_dependencies
 
+        store_existing_checkout_options
         fetch_external_sources if allow_fetches
         @result.specs_by_target = resolve_dependencies
         @result.specifications  = generate_specifications
@@ -335,6 +336,15 @@ module Pod
         end
       end
 
+      def store_existing_checkout_options
+        podfile.dependencies.select(&:external_source).each do |dep|
+          if checkout_options = lockfile && lockfile.checkout_options_for_pod_named(dep.root_name)
+            sandbox.store_checkout_source(dep.root_name, checkout_options)
+          end
+        end
+      end
+
+
       # Converts the Podfile in a list of specifications grouped by target.
       #
       # @note   As some dependencies might have external sources the resolver