feat(tvix/eval): Implement builtins.removeAttrs r/5102

Change-Id: I28910991a0108436a42ac7bf3458f9180a44154e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6928
Reviewed-by: Adam Joseph <adam@westernsemico.com>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

4 files changed, 31 insertions, 1 deletions

diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs
index c603264c1e27..47e4eea63d90 100644
--- a/tvix/eval/src/builtins/mod.rs
+++ b/tvix/eval/src/builtins/mod.rs
@@ -4,7 +4,7 @@
 //! available builtins in Nix.
 
 use std::cmp;
-use std::collections::{BTreeMap, HashMap};
+use std::collections::{BTreeMap, HashMap, HashSet};
 use std::path::PathBuf;
 
 use crate::{
@@ -362,6 +362,25 @@ fn pure_builtins() -> Vec<Builtin> {
             &[false, false],
             |args: Vec<Value>, vm: &mut VM| arithmetic_op!(&*args[0].force(vm)?, &*args[1].force(vm)?, *),
         ),
+        Builtin::new(
+            "removeAttrs",
+            &[true, true],
+            |args: Vec<Value>, _: &mut VM| {
+                let attrs = args[0].to_attrs()?;
+                let keys = args[1]
+                    .to_list()?
+                    .into_iter()
+                    .map(|v| v.to_str())
+                    .collect::<Result<HashSet<_>, _>>()?;
+                let mut res = BTreeMap::new();
+                for (k, v) in attrs.iter() {
+                    if !keys.contains(k) {
+                        res.insert(k.clone(), v.clone());
+                    }
+                }
+                Ok(Value::attrs(NixAttrs::from_map(res)))
+            },
+        ),
         Builtin::new("splitVersion", &[true], |args: Vec<Value>, _: &mut VM| {
             let s = args[0].to_str()?;
             let s = VersionPartsIter::new(s.as_str());
diff --git a/tvix/eval/src/tests/tvix_tests/eval-fail-remove.nix b/tvix/eval/src/tests/tvix_tests/eval-fail-remove.nix
new file mode 100644
index 000000000000..539e0eb0a6f6
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-fail-remove.nix
@@ -0,0 +1,5 @@
+let {
+  attrs = {x = 123; y = 456;};
+
+  body = (removeAttrs attrs ["x"]).x;
+}
\ No newline at end of file
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-remove.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-remove.exp
new file mode 100644
index 000000000000..8d38505c1686
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-remove.exp
@@ -0,0 +1 @@
+456
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-remove.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-remove.nix
new file mode 100644
index 000000000000..4ad5ba897fa7
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-remove.nix
@@ -0,0 +1,5 @@
+let {
+  attrs = {x = 123; y = 456;};
+
+  body = (removeAttrs attrs ["x"]).y;
+}
\ No newline at end of file