operator: fix overrides of additionalCmdFlags

A regression was introduced that broke the ability to override CLI flags of the
operator due to the arguments of `helmette.Merge` being backwards.

This commit corrects the arguments, adds a regression test, and updates the
docs of `helmette.Merge` to clearly indicate how it should be used.

Author: chrisseto

gotohelm/helmette/sprig.go

@@ -166,6 +166,14 @@ func Keys[K comparable, V any](m map[K]V) []K {
 }
 
 // Merge is a go equivalent of sprig's `merge`.
+//
+// It merges two or more maps into one, giving precedence from left
+// to right.
+//
+// Unlink sprig, a modified map is returned rather than modifying the left most
+// map.
+//
+//	Merge(map[int]int{1:1,2:2},map[int]int{1:2,2:3,3:4}) // map[int]int{1:1,2:2,3:4}
 func Merge[K comparable, V any](sources ...map[K]V) map[K]V {
 	dst := map[K]V{}
 	for _, src := range sources {

operator/chart/chart_test.go

@@ -396,7 +396,6 @@ func TestTemplate(t *testing.T) {
 	goldens := testutil.NewTxTar(t, "testdata/template-cases.golden.txtar")
 
 	for _, tc := range append(casesArchive.Files, generatedCasesArchive.Files...) {
-		tc := tc
 		t.Run(tc.Name, func(t *testing.T) {
 			t.Parallel()
 

operator/chart/deployment.go

@@ -335,7 +335,7 @@ func operatorArguments(dot *helmette.Dot) []string {
 	userProvided := chartutil.ParseFlags(values.AdditionalCmdFlags)
 
 	var flags []string
-	for key, value := range helmette.SortedMap(helmette.Merge(defaults, userProvided)) {
+	for key, value := range helmette.SortedMap(helmette.Merge(userProvided, defaults)) {
 		if value == "" {
 			flags = append(flags, key)
 		} else {

operator/chart/templates/_deployment.go.tpl

@@ -155,7 +155,7 @@
 {{- end -}}
 {{- $userProvided := (get (fromJson (include "chartutil.ParseFlags" (dict "a" (list $values.additionalCmdFlags)))) "r") -}}
 {{- $flags := (coalesce nil) -}}
-{{- range $key, $value := (merge (dict) $defaults $userProvided) -}}
+{{- range $key, $value := (merge (dict) $userProvided $defaults) -}}
 {{- if (eq $value "") -}}
 {{- $flags = (concat (default (list) $flags) (list $key)) -}}
 {{- else -}}