mix release includes overlays even after source files are removed

[emilianobovetti]

Elixir and Erlang/OTP versions

Erlang/OTP 25 [erts-13.2.2.6] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit:ns]

Elixir 1.15.7 (compiled with Erlang/OTP 25)

Erlang/OTP 26 [erts-14.2.2] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit:ns]

Elixir 1.17.0-dev (73ef1c5) (compiled with Erlang/OTP 26)

Operating system

Linux 6.1.78 #1-NixOS SMP PREEMPT_DYNAMIC x86_64 GNU/Linux

Current behavior

Here are the steps to reproduce the problem:

1. Write a file into the rel/overlays directory.
2. Run mix release.
3. Delete the file from the rel/overlays directory.
4. Run mix release --overwrite.
5. The file is still included into the release.

Expected behavior

Here's a test case that describes the behavior I would expect:

  test "stale files in overlays" do
    in_fixture("release_test", fn ->
      Mix.Project.in_project(:release_test, ".", fn _ ->
        File.mkdir_p!("rel/overlays")
        File.write!("rel/overlays/file1", "hello")
        File.write!("rel/overlays/file2", "world")

        root = Path.absname("_build/dev/rel/release_test")

        Mix.Task.run("release")
        assert root |> Path.join("file1") |> File.read!() == "hello"
        assert root |> Path.join("file2") |> File.read!() == "world"

        File.rm!("rel/overlays/file2")

        Mix.Task.rerun("release", ["--overwrite"])
        refute root |> Path.join("file2") |> File.exists?()
      end)
    end)
  end

Fix attempt

By removing the whole release directory before running a new release the issue is fixed, but I'm afraid my approach is too naive.

ref: emilianobovetti@905327e

[josevalim]

In this case the docs for --overwrite are unclear, I will push a fix. If you want no overlap, then nuking the previous release is better. :)