I find the compile time warnings very useful, but I can occasionally miss them, especially if it's on a pull request where the tests are running on a CI server.
Ideally I would specify something in the project mix file that would make the compiler more strict.
I want to this to be in effect for all mix tasks, and I do not want to have to pass the flag to the command, as this is easy to forget.
For example with a project with a compiler warning, this command should fail
mix clean && mix compile
As should this one
mix clean && mix test
Possible to some extent. There is a flag --warnings-as-errors in elixirc command.
☁ hello_elixir [master] ⚡ elixirc
Usage: elixirc [elixir switches] [compiler switches] [.ex files]
-o The directory to output compiled files
--no-docs Do not attach documentation to compiled modules
--no-debug-info Do not attach debug info to compiled modules
--ignore-module-conflict
--warnings-as-errors Treat warnings as errors and return non-zero exit code
--verbose Print informational messages.
** Options given after -- are passed down to the executed code
** Options can be passed to the erlang runtime using ELIXIR_ERL_OPTIONS
** Options can be passed to the erlang compiler using ERL_COMPILER_OPTIONS
For a module like this, with a warning:
defmodule Useless do
defp another_userless, do: nil
end
When you compile without the flag:
☁ 01_language [master] ⚡ elixirc useless.ex
useless.ex:2: warning: function another_userless/0 is unused
☁ 01_language [master] ⚡ echo $?
0
You get the return code as 0.
But when you compile with the flag --warnings-as-errors, it returns an exit code of 1.
☁ 01_language [master] ⚡ elixirc --warnings-as-errors useless.ex
useless.ex:1: warning: redefining module Useless
useless.ex:2: warning: function another_userless/0 is unused
☁ 01_language [master] ⚡ echo $?
1
You can use this return code in your compile script for break the build process.