Merge pull request #31957 from Mentigen/add-mustToToml

feat(engine): add mustToToml template function

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,
@@ -148,10 +149,11 @@ func fromYAMLArray(str string) []any {
 	return a
 }
 
-// toTOML takes an interface, marshals it to toml, and returns a string. It will
-// always return a string, even on marshal error (empty string).
+// toTOML takes an interface, marshals it to toml, and returns a string.
+// On marshal error it returns the error string.
 //
-// This is designed to be called from a template.
+// This is designed to be called from a template. Use mustToToml if you need
+// the template to fail hard on marshal errors.
 func toTOML(v any) string {
 	b := bytes.NewBuffer(nil)
 	e := toml.NewEncoder(b)
@@ -162,6 +164,21 @@ func toTOML(v any) string {
 	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)
+	err := e.Encode(v)
+	if err != nil {
+		panic(err)
+	}
+	return b.String()
+}
+
 // fromTOML converts a TOML document into a map[string]interface{}.
 //
 // This is not a general-purpose TOML parser, and will not parse all valid

pkg/engine/funcs_test.go

@@ -159,6 +159,13 @@ keyInElement1 = "valueInElement1"`,
 		tpl:    `{{ toJson . }}`,
 		expect: "", // should return empty string and swallow error
 		vars:   loopMap,
+	}, {
+		tpl:  `{{ mustToToml . }}`,
+		vars: map[int]string{1: "one"}, // non-string key is invalid in TOML
+	}, {
+		tpl:    `{{ mustToToml . }}`,
+		expect: "foo = \"bar\"\n", // should succeed and return TOML string
+		vars:   map[string]string{"foo": "bar"},
 	},
 	}