feat(tvix/eval): Implement builtins.readFile r/5095

Change-Id: If3fd0b087009a2bfbad8bb7aca0aa20de906eb12
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6921
Tested-by: BuildkiteCI
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: tazjin <tazjin@tvl.su>

1 files changed, 7 insertions, 0 deletions

diff --git a/tvix/eval/src/value/string.rs b/tvix/eval/src/value/string.rs
index 876b1abe6b40..d146ee4cec95 100644
--- a/tvix/eval/src/value/string.rs
+++ b/tvix/eval/src/value/string.rs
@@ -1,6 +1,7 @@
 //! This module implements Nix language strings and their different
 //! backing implementations.
 use smol_str::SmolStr;
+use std::ffi::OsStr;
 use std::hash::Hash;
 use std::ops::Deref;
 use std::path::Path;
@@ -186,6 +187,12 @@ impl AsRef<str> for NixString {
     }
 }
 
+impl AsRef<OsStr> for NixString {
+    fn as_ref(&self) -> &OsStr {
+        self.as_str().as_ref()
+    }
+}
+
 impl AsRef<Path> for NixString {
     fn as_ref(&self) -> &Path {
         self.as_str().as_ref()