Ecto app in umbrella jason error

[mainlymortal]

Environment

• Elixir version: 1.8
• Phoenix version: 1.4
• Operating system: macOS

Expected behavior

mix ecto.migrate runs all pending migrations.

Actual behavior

Error...

18:40:25.636 [info] Application decimal exited: :stopped

18:40:25.638 [info] Application db_connection exited: :stopped

18:40:25.638 [info] Application connection exited: :stopped

18:40:25.639 [info] Application telemetry exited: :stopped
** (MatchError) no match of right hand side value: {:error, {:jason, {'no such file or directory', 'jason.app'}}}
(ecto_sql) lib/mix/ecto_sql.ex:9: Mix.EctoSQL.ensure_started/2
(ecto_sql) lib/mix/tasks/ecto.migrations.ex:43: anonymous fn/3 in Mix.Tasks.Ecto.Migrations.run/3
(elixir) lib/enum.ex:1327: Enum."-map/2-lists^map/1-0-"/2
(ecto_sql) lib/mix/tasks/ecto.migrations.ex:40: Mix.Tasks.Ecto.Migrations.run/3
(mix) lib/mix/task.ex:331: Mix.Task.run_task/3
(mix) lib/mix/cli.ex:79: Mix.CLI.run_task/2

mix ecto.migrations/ecto.reset e.t.c. show the same issue.

Notes

This has been bugging me all day. I created an umbrella phoenix project and 9/10 times when it comes to migrations (and similar mix commands) I get this error. If i delete the _build directory then compile only the ecto app then migrations work. If i compile from the umbrella root or the web app then migrations fail with the above error.

The actual solution seems to be to add {:jason, "~> 1.0"} to the mix deps for the ecto app but in previous versions i've never had to do this.

[josevalim]

This is a bug in Elixir but Phoenix should likely consider adding :jason as a dependency to the ecto app too.

[josevalim]

Fixed on Elixir v1.8.1 but, as said, I would recommend adding jason as a dep in the ecto app too. 👍 Thanks for the report!

[mainlymortal]

Thanks, @josevalim. I just tested it and it does indeed work (not that I ever doubted you haha). So are you suggesting the umbrella templates should be modified to include the jason dependancy by default? If so what is it being used for if the ecto app now works without the dependancy?

[josevalim]

:D

@mainlymortal the reason to add jason is because if you want to use a :map field (which requires a JSON lib) then it will already be there. Also, we already include jason in the web app, so it is not like it will make a big difference to have it in both at the end of the day.