fixed more messages extension edge cases

lib/cocoapods/installer/analyzer.rb

@@ -274,7 +274,7 @@ module Pod
           host_uuids = []
           aggregate_target_user_projects.product(target.user_targets).each do |user_project, user_target|
             host_targets = user_project.host_targets_for_embedded_target(user_target)
-            host_targets.map(&:product_type).each do |product_type|
+            host_targets.map(&:symbol_type).each do |product_type|
               target.add_host_target_product_type(product_type)
             end
             host_uuids += host_targets.map(&:uuid)

lib/cocoapods/installer/user_project_integrator/target_integrator.rb

@@ -21,9 +21,11 @@ module Pod
         # frameworks are embedded in the output directory / product bundle.
         #
         # @note This does not include :app_extension or :watch_extension because
-        # these types must have their frameworks embedded in their host targets
+        # these types must have their frameworks embedded in their host targets.
+        # For messages extensions, this only applies if it's embedded in a messages
+        # application.
         #
-        EMBED_FRAMEWORK_TARGET_TYPES = [:application, :unit_test_bundle, :ui_test_bundle, :watch2_extension].freeze
+        EMBED_FRAMEWORK_TARGET_TYPES = [:application, :unit_test_bundle, :ui_test_bundle, :watch2_extension, :messages_extension].freeze
 
         # @return [String] the name of the embed frameworks phase
         #
@@ -121,6 +123,7 @@ module Pod
         #       will have their frameworks embedded in their host targets.
         #
         def remove_embed_frameworks_script_phase_from_embedded_targets
+          return unless target.requires_host_target?
           native_targets.each do |native_target|
             if AggregateTarget::EMBED_FRAMEWORKS_IN_HOST_TARGET_TYPES.include? native_target.symbol_type
               remove_embed_frameworks_script_phase(native_target)
@@ -201,6 +204,7 @@ module Pod
         #         directory / product bundle.
         #
         def native_targets_to_embed_in
+          return [] if target.requires_host_target?
           native_targets.select do |target|
             EMBED_FRAMEWORK_TARGET_TYPES.include?(target.symbol_type)
           end

lib/cocoapods/target/aggregate_target.rb

@@ -8,6 +8,9 @@ module Pod
     attr_reader :target_definition
 
     # Product types where the product's frameworks must be embedded in a host target
+    #
+    # @note :messages_extension only applies when it is embedded in an app (as opposed to a messages app)
+    #
     EMBED_FRAMEWORKS_IN_HOST_TARGET_TYPES = [:app_extension, :framework, :messages_extension, :watch_extension].freeze
 
     # Initialize a new instance
@@ -24,7 +27,7 @@ module Pod
       @search_paths_aggregate_targets = []
       @file_accessors = []
       @xcconfigs = {}
-      @host_target_types = [] # Product types of the host target, if this target is embedded
+      @host_target_types = Set.new # Product types of the host target, if this target is embedded
     end
 
     # Adds product type to the list of product types for the host