Maintain backwards compatibility with Poison users

Author: chrismccord

installer/templates/phx_single/config/config.exs

@@ -24,9 +24,11 @@ config :logger, :console,
   format: "$time $metadata[$level] $message\n",
   metadata: [:request_id]
 
-# Use Jason for JSON parsing in Phoenix
+# Use Jason for JSON parsing in Phoenix<%= if ecto do %> and Ecto<% end %>
 config :phoenix, :format_encoders, json: Jason
-
+<%= if ecto do %>
+config :ecto, :json_library, Jason
+<% end %>
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 import_config "#{Mix.env}.exs"

installer/templates/phx_umbrella/apps/app_name/config/config.exs

@@ -1,5 +1,6 @@
 use Mix.Config
 
 <%= if ecto do %>config :<%= app_name %>, ecto_repos: [<%= app_module %>.Repo]<% end %>
+<%= if ecto do %>config :ecto, :json_library, Jason<% end %>
 
 import_config "#{Mix.env}.exs"

installer/test/phx_new_test.exs

@@ -33,6 +33,7 @@ defmodule Mix.Tasks.Phx.NewTest do
       assert_file "phx_blog/config/config.exs", fn file ->
         assert file =~ "ecto_repos: [PhxBlog.Repo]"
         assert file =~ "config :phoenix, :format_encoders, json: Jason"
+        assert file =~ "config :ecto, :json_library, Jason"
         refute file =~ "namespace: PhxBlog"
         refute file =~ "config :phx_blog, :generators"
       end
@@ -165,6 +166,7 @@ defmodule Mix.Tasks.Phx.NewTest do
       assert_file "phx_blog/config/config.exs", fn file ->
         refute file =~ "config :phx_blog, :generators"
         refute file =~ "ecto_repos:"
+        refute file =~ "config :ecto, :json_library, Jason"
       end
 
       assert_file "phx_blog/config/dev.exs", &refute(&1 =~ config)

installer/test/phx_new_umbrella_test.exs

@@ -58,6 +58,7 @@ defmodule Mix.Tasks.Phx.New.UmbrellaTest do
       end
       assert_file app_path(@app, "config/config.exs"), fn file ->
         assert file =~ "ecto_repos: [PhxUmb.Repo]"
+        assert file =~ "config :ecto, :json_library, Jason"
         refute file =~ "namespace"
         refute file =~ "config :phx_blog_web, :generators"
       end
@@ -214,6 +215,7 @@ defmodule Mix.Tasks.Phx.New.UmbrellaTest do
       assert_file app_path(@app, "config/config.exs"), fn file ->
         refute file =~ "config :phx_blog_web, :generators"
         refute file =~ "ecto_repos:"
+        refute file =~ "config :ecto, :json_library, Jason"
       end
       assert_file web_path(@app, "config/config.exs"), fn file ->
         refute file =~ "config :phx_blog_web, :generators"

lib/phoenix.ex

@@ -35,8 +35,9 @@ defmodule Phoenix do
   @doc false
   def start(_type, _args) do
     # Warm up caches
-    _ = Phoenix.Template.engines
+    _ = Phoenix.Template.engines()
     _ = Phoenix.Template.format_encoder("index.html")
+    warn_on_missing_format_encoders()
 
     # Configure proper system flags from Phoenix only
     if stacktrace_depth = Application.get_env(:phoenix, :stacktrace_depth) do
@@ -47,8 +48,6 @@ defmodule Phoenix do
     import Supervisor.Spec
 
     children = [
-      # Ensure format encoders are loaded before starting
-      worker(Task, [fn -> ensure_format_encoders() end], restart: :transient),
       # Code reloading must be serial across all Phoenix apps
       worker(Phoenix.CodeReloader.Server, [])
     ]
@@ -57,15 +56,16 @@ defmodule Phoenix do
   end
 
   @doc false
+  # TODO remove Poison default in 2.0
   def json do
     :phoenix
     |> Application.fetch_env!(:format_encoders)
-    |> Keyword.get(:json, Jason)
+    |> Keyword.get(:json, Poison)
   end
 
-  defp ensure_format_encoders do
+  defp warn_on_missing_format_encoders do
     for {format, mod} <- Application.fetch_env!(:phoenix, :format_encoders) do
-      Code.ensure_loaded?(mod) || raise """
+      Code.ensure_loaded?(mod) || IO.write :sterr, """
       failed to load #{inspect(mod)} for Phoenix :#{format} encoder
       (module #{inspect(mod)} is not available)
 

lib/phoenix/template.ex

@@ -104,7 +104,6 @@ defmodule Phoenix.Template do
 
   alias Phoenix.Template
 
-  @encoders [html: Phoenix.Template.HTML, json: Jason, js: Phoenix.Template.HTML]
   @engines  [eex: Phoenix.Template.EExEngine, exs: Phoenix.Template.ExsEngine]
   @default_pattern "*"
 
@@ -242,7 +241,7 @@ defmodule Phoenix.Template do
         encoders
       :error ->
         encoders =
-          @encoders
+          default_encoders()
           |> Keyword.merge(raw_config(:format_encoders))
           |> Enum.filter(fn {_, v} -> v end)
           |> Enum.into(%{}, fn {k, v} -> {".#{k}", v} end)
@@ -251,6 +250,10 @@ defmodule Phoenix.Template do
     end
   end
 
+  defp default_encoders do
+    [html: Phoenix.Template.HTML, json: Phoenix.json(), js: Phoenix.Template.HTML]
+  end
+
   @doc """
   Returns a keyword list with all template engines
   extensions followed by their modules.

test/test_helper.exs

@@ -3,6 +3,10 @@ Code.require_file("support/router_helper.exs", __DIR__)
 # Starts web server applications
 Application.ensure_all_started(:cowboy)
 
+# Clear format encoder cache from startup and inject Jason
+Application.delete_env(:phoenix, :compiled_format_encoders)
+Application.put_env(:phoenix, :format_encoders, json: Jason)
+
 # Used whenever a router fails. We default to simply
 # rendering a short string.
 defmodule Phoenix.ErrorView do