feat(tvix/eval): use `EvalIO::import_path` when coercing paths r/5467

This "ties the knot" of importing files into a store when referring
to them through path literals, e.g. inside of strings.

I'm not yet sure if this interface is sufficient for
builtins.path (which we haven't implemented at all yet), but it's
enough to wire up eval & store initially.

In the default implementations nothing interesting happens in this
function at all.

Change-Id: Ie01ff4161617d1e743a68dbd1a5e54c1b40c0990
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7582
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

1 files changed, 2 insertions, 1 deletions

diff --git a/tvix/eval/src/value/mod.rs b/tvix/eval/src/value/mod.rs
index 583d0c38e46e..3e59c19c3196 100644
--- a/tvix/eval/src/value/mod.rs
+++ b/tvix/eval/src/value/mod.rs
@@ -185,7 +185,8 @@ impl Value {
             // sequences without NUL bytes, whereas Tvix only allows valid
             // Unicode. See also b/189.
             (Value::Path(p), kind) if kind != CoercionKind::ThunksOnly => {
-                Ok(p.to_string_lossy().into_owned().into())
+                let imported = vm.io().import_path(p)?;
+                Ok(imported.to_string_lossy().into_owned().into())
             }
 
             // Attribute sets can be converted to strings if they either have an