chore(perf): Pre-allocate where possible (enable prealloc linter) (#88952)

* chore(perf): Pre-allocate where possible (enable prealloc linter)

Signed-off-by: Dave Henderson <dave.henderson@grafana.com>

* fix TestAlertManagers_buildRedactedAMs

Signed-off-by: Dave Henderson <dave.henderson@grafana.com>

* prealloc a slice that appeared after rebase

Signed-off-by: Dave Henderson <dave.henderson@grafana.com>

---------

Signed-off-by: Dave Henderson <dave.henderson@grafana.com>

pkg/util/strings.go

@@ -48,11 +48,13 @@ func SplitString(str string) []string {
 		return res
 	}
 
-	var result []string
 	matches := stringListItemMatcher.FindAllString(str, -1)
-	for _, match := range matches {
-		result = append(result, strings.Trim(match, "\""))
+
+	result := make([]string, len(matches))
+	for i, match := range matches {
+		result[i] = strings.Trim(match, "\"")
 	}
+
 	return result
 }
 

pkg/util/tls.go

@@ -30,22 +30,26 @@ func TlsCiphersToIDs(names []string) ([]uint16, error) {
 		// no ciphers specified, use defaults
 		return nil, nil
 	}
-	var ids []uint16
-	var missing []string
 
 	ciphers := tls.CipherSuites()
-	var cipherMap = make(map[string]uint16, len(ciphers))
+
+	cipherMap := make(map[string]uint16, len(ciphers))
 	for _, cipher := range ciphers {
 		cipherMap[cipher.Name] = cipher.ID
 	}
 
+	missing := []string{}
+	ids := make([]uint16, 0, len(names))
+
 	for _, name := range names {
 		name = strings.ToUpper(name)
+
 		id, ok := cipherMap[name]
 		if !ok {
 			missing = append(missing, name)
 			continue
 		}
+
 		ids = append(ids, id)
 	}