Mix cmd regression

Elixir and Erlang/OTP versions

Erlang/OTP 28 [erts-16.1] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [jit:ns]

Elixir 1.19.0-rc.0 (compiled with Erlang/OTP 28)

Operating system

Ubuntu 22.04

Current behavior

According to Mix documentation, it should be possible run a relative script with mix cmd, for example mix cmd priv/world.sh in an alias. See:

elixir/lib/mix/lib/mix.ex

Lines 273 to 291 in f089571

    
             Another use case of aliases is to run Elixir scripts and shell 
        
             commands, for example: 
        
                 # priv/hello1.exs 
        
                 IO.puts("Hello One") 
        
                 # priv/hello2.exs 
        
                 IO.puts("Hello Two") 
        
                 # priv/world.sh 
        
                 #!/bin/sh 
        
                 echo "world!" 
        
                 # mix.exs 
        
                 defp aliases do 
        
                   [ 
        
                     some_alias: ["hex.info", "run priv/hello1.exs", "cmd priv/world.sh"] 
        
                   ] 
        
                 end

We use this in some of our repositories in aliases, and the fix is simple enough for that use case
"cmd #{Path.absname("./priv/world.sh")}"

Expected behavior

I would expect mix cmd to be able to run relative scripts in line with the documentation.

If this is not to be fixed, I would expect the documentation to be updated and for this to be logged as a deprecation in the 1.19 release changelog.

I am quite certain this was introduced by #13751 even though I have not confirmed it, but I can see in the System.cmd code that relative paths are not allowed which throws the enoent error that I am seeing.

The PR you linked changes only Rebar, But I have identified the root cause and submitted a PR. Thanks for the report.

Thanks for the quick triage!

I don't think the PR I linked only changes Rebar. It makes changes to Mix.Shell.cmd, swapping System.shell for System.cmd, which behave differently and potentially affecting everything that calls Mix.shell().cmd(). Or am I misunderstanding?

~~https://github.com/elixir-lang/elixir/pull/13751/files#diff-eebd051a7df756d115cbc7a76ef43ef6a461182c0485dfeda426ff7bb79bd16eR134-R139~~

Edit: Ok nevermind, I see what you mean. Accepting the tuple form was added in that PR, and another one then uses that one for the mix cmd.

	Another use case of aliases is to run Elixir scripts and shell
	commands, for example:

	# priv/hello1.exs
	IO.puts("Hello One")

	# priv/hello2.exs
	IO.puts("Hello Two")

	# priv/world.sh
	#!/bin/sh
	echo "world!"

	# mix.exs
	defp aliases do
	[
	some_alias: ["hex.info", "run priv/hello1.exs", "cmd priv/world.sh"]
	]
	end