diff --git a/pkg/engine/funcs.go b/pkg/engine/funcs.go
index ba842a51a..957c4af56 100644
--- a/pkg/engine/funcs.go
+++ b/pkg/engine/funcs.go
@@ -50,6 +50,7 @@ func funcMap() template.FuncMap {
 	// Add some extra functionality
 	extra := template.FuncMap{
 		"toToml":        toTOML,
+		"mustToToml":    mustToTOML,
 		"fromToml":      fromTOML,
 		"toYaml":        toYAML,
 		"mustToYaml":    mustToYAML,
@@ -155,9 +156,23 @@ func fromYAMLArray(str string) []any {
 func toTOML(v any) string {
 	b := bytes.NewBuffer(nil)
 	e := toml.NewEncoder(b)
-	err := e.Encode(v)
-	if err != nil {
-		return err.Error()
+	if err := e.Encode(v); err != nil {
+		// Errors are intentionally swallowed in templates.
+		return ""
+	}
+	return b.String()
+}
+
+// mustToTOML takes an interface, marshals it to toml, and returns a string.
+// It will panic if there is an error.
+//
+// This is designed to be called from a template when you need to ensure that
+// the output TOML is valid.
+func mustToTOML(v any) string {
+	b := bytes.NewBuffer(nil)
+	e := toml.NewEncoder(b)
+	if err := e.Encode(v); err != nil {
+		panic(err)
 	}
 	return b.String()
 }
diff --git a/pkg/engine/funcs_test.go b/pkg/engine/funcs_test.go
index 48202454e..1fe290869 100644
--- a/pkg/engine/funcs_test.go
+++ b/pkg/engine/funcs_test.go
@@ -25,7 +25,6 @@ import (
 )
 
 func TestFuncs(t *testing.T) {
-	//TODO write tests for failure cases
 	tests := []struct {
 		tpl, expect string
 		vars        any
@@ -136,10 +135,9 @@ keyInElement1 = "valueInElement1"`,
 		assert.Equal(t, tt.expect, b.String(), tt.tpl)
 	}
 
-	loopMap := map[string]any{
-		"foo": "bar",
+	nonSerializable := map[string]any{
+		"foo": struct{ Fn func() }{},
 	}
-	loopMap["loop"] = []any{loopMap}
 
 	mustFuncsTests := []struct {
 		tpl    string
@@ -147,18 +145,25 @@ keyInElement1 = "valueInElement1"`,
 		vars   any
 	}{{
 		tpl:  `{{ mustToYaml . }}`,
-		vars: loopMap,
+		vars: nonSerializable,
 	}, {
 		tpl:  `{{ mustToJson . }}`,
-		vars: loopMap,
+		vars: nonSerializable,
+	}, {
+		tpl:  `{{ mustToToml . }}`,
+		vars: nonSerializable,
 	}, {
 		tpl:    `{{ toYaml . }}`,
 		expect: "", // should return empty string and swallow error
-		vars:   loopMap,
+		vars:   nonSerializable,
 	}, {
 		tpl:    `{{ toJson . }}`,
 		expect: "", // should return empty string and swallow error
-		vars:   loopMap,
+		vars:   nonSerializable,
+	}, {
+		tpl:    `{{ toToml . }}`,
+		expect: "", // should return empty string and swallow error
+		vars:   nonSerializable,
 	},
 	}