Can't set a build-arg containing = from the command line

[mexicat]

Describe the bug
I have a build arg I need to pass to fly deploy as part of a CI process. This build arg contains the equal symbol =. No matter how I escape it, flyctl refuses to accept it:

$ fly deploy --build-arg MY_ARG="some=value"
==> Validating app configuration
--> Validating app configuration done
Services
TCP 80/443 ⇢ 8080
Error invalid build-arg: 'MY_ARG=some=value': must be in the format NAME=VALUE

$ fly deploy --build-arg MY_ARG="some\=value"
==> Validating app configuration
--> Validating app configuration done
Services
TCP 80/443 ⇢ 8080
Error invalid build-arg: 'MY_ARG=some\=value': must be in the format NAME=VALUE

Putting the build arg in fly.toml makes it work, but I don't want to commit this build arg.

The cause seems to be these lines of validation in the source code, that naively check for the amount of =s:

flyctl/internal/cmdutil/flags.go

Lines 13 to 16 in 1d9b462

	parts := strings.Split(arg, "=")
	if len(parts) != 2 {
	return nil, fmt.Errorf("'%s': must be in the format NAME=VALUE", arg)
	}

Unfortunately I don't know enough Go to be able to submit a pull request.

[michaeldwan]

@mexicat this should be fixed now, sorry about that

[mexicat]

Whoa, that was quick! Thank you!