🐞 Inconsistent file mounting behavior when name isn't specified

[sagikazarmark]

What is the issue?

I'm supposed to be able to do this:

dag.Container().WithFile("", file)
 
dag.Directory().WithFile("", file)

When no path is specified, the file should be mounted in the current directory with it's current name.

Unfortunately, Dagger behaves differently in different scenarios which makes mounting files like this unreliable.

(The unfortunate consequence is every higher level API that allows mounting a file in a lower level container requires a second name parameter too)

Dagger version

dagger v0.11.4 (registry.dagger.io/engine) darwin/arm64

Steps to reproduce

package main

type Repro struct{}

func (m *Repro) EmptyDir() *Container {
	dir := dag.Directory().
		WithDirectory("bar", dag.Directory().WithFile("", dag.CurrentModule().Source().File("baz.conf")))

	return dag.Container().
		From("cgr.dev/chainguard/wolfi-base").
		WithDirectory("/etc/foo", dir).
		WithExec([]string{"tree", "/etc/foo"})
}

func (m *Repro) Dir() *Container {
	dir := dag.Directory().
		WithDirectory("bar", dag.Directory())

	dir2 := dir.Directory("bar").WithFile("", dag.CurrentModule().Source().File("baz.conf"))

	dir = dir.WithDirectory("bar", dir2)

	return dag.Container().
		From("cgr.dev/chainguard/wolfi-base").
		WithDirectory("/etc/foo", dir).
		WithExec([]string{"tree", "/etc/foo"})
}

func (m *Repro) Ctr() *Container {
	dir := dag.Directory().
		WithDirectory("bar", dag.Directory())

	ctr := dag.Container().
		From("cgr.dev/chainguard/wolfi-base").
		WithDirectory("/etc/foo", dir).
		WithExec([]string{"tree", "/etc/foo"})

	dir2 := ctr.Directory("/etc/foo/bar").WithFile("", dag.CurrentModule().Source().File("baz.conf"))

	return ctr.WithDirectory("/etc/foo/bar", dir2)
}

func (m *Repro) Ctr2() *Container {
	return dag.Container().
		From("cgr.dev/chainguard/wolfi-base").
		WithFile("/etc/foo/bar/", dag.CurrentModule().Source().File("baz.conf")).
		WithExec([]string{"tree", "/etc/foo"})
}

func (m *Repro) File(path *File) *Container {
	return dag.Container().
		From("cgr.dev/chainguard/wolfi-base").
		WithFile("/etc/foo/bar/", path).
		WithExec([]string{"tree", "/etc/foo"})
}

touch baz.conf

dagger call empty-dir stdout
dagger call dir stdout
dagger call ctr stdout
dagger call ctr2 stdout
dagger call file --path ./baz.conf stdout

nix run github:dagger/nix#dagger -- call empty-dir stdout
nix run github:dagger/nix#dagger -- call dir stdout
nix run github:dagger/nix#dagger -- call ctr stdout
nix run github:dagger/nix#dagger -- call ctr2 stdout
nix run github:dagger/nix#dagger -- call file --path ./baz.conf stdout

Log output

dagger call empty-dir stdout
/etc/foo
`-- bar
    `-- baz.conf

1 directories, 1 files

dagger call dir stdout
/etc/foo
`-- bar

0 directories, 1 files

dagger call ctr stdout
/etc/foo
`-- bar

1 directories, 0 files

dagger call ctr2 stdout
/etc/foo
`-- bar
    `-- bar

1 directories, 1 files

dagger call file --path ./baz.conf stdout
/etc/foo
`-- bar
    `-- bar

1 directories, 1 files