Preserve runtime error node IDs from Resolve

When absoluteAttribute.Resolve() encounters a *types.Err variable value,
return it directly rather than calling Unwrap(). The Unwrap call strips
the Err wrapper and its node ID, causing callers to re-label the error
with the observation site's ID instead of the originating expression's ID.

Additionally, avoid double-wrapping *types.Err values returned from
Resolve in evalTestOnly, evalAttr, and evalExhaustiveConditional. When
the error is already a *types.Err, pass it to LabelErrNode directly so
that a pre-existing non-zero node ID is preserved.

Fixes #1191

Author: efd6

interpreter/attributes.go

@@ -349,7 +349,7 @@ func (a *absoluteAttribute) Resolve(vars Activation) (any, error) {
 		obj, found := v.ResolveName(nm)
 		if found {
 			if celErr, ok := obj.(*types.Err); ok {
-				return nil, celErr.Unwrap()
+				return nil, celErr
 			}
 			obj, isOpt, err := applyQualifiers(v, obj, a.qualifiers)
 			if err != nil {

interpreter/interpretable.go

@@ -167,6 +167,9 @@ func (test *evalTestOnly) Eval(ctx Activation) ref.Val {
 	val, err := test.Resolve(ctx)
 	// Return an error if the resolve step fails
 	if err != nil {
+		if celErr, ok := err.(*types.Err); ok {
+			return types.LabelErrNode(test.id, celErr)
+		}
 		return types.LabelErrNode(test.id, types.WrapErr(err))
 	}
 	if optVal, isOpt := val.(*types.Optional); isOpt {
@@ -1174,11 +1177,17 @@ func (cond *evalExhaustiveConditional) Eval(ctx Activation) ref.Val {
 	}
 	if cBool {
 		if tErr != nil {
+			if celErr, ok := tErr.(*types.Err); ok {
+				return types.LabelErrNode(cond.id, celErr)
+			}
 			return types.LabelErrNode(cond.id, types.WrapErr(tErr))
 		}
 		return cond.adapter.NativeToValue(tVal)
 	}
 	if fErr != nil {
+		if celErr, ok := fErr.(*types.Err); ok {
+			return types.LabelErrNode(cond.id, celErr)
+		}
 		return types.LabelErrNode(cond.id, types.WrapErr(fErr))
 	}
 	return cond.adapter.NativeToValue(fVal)
@@ -1219,6 +1228,9 @@ func (a *evalAttr) Adapter() types.Adapter {
 func (a *evalAttr) Eval(ctx Activation) ref.Val {
 	v, err := a.attr.Resolve(ctx)
 	if err != nil {
+		if celErr, ok := err.(*types.Err); ok {
+			return types.LabelErrNode(a.ID(), celErr)
+		}
 		return types.LabelErrNode(a.ID(), types.WrapErr(err))
 	}
 	return a.adapter.NativeToValue(v)