Alerting: Collate rule_group column as binary (#114365)

* fix: collate rule_group column as utf8mb4_bin

This ensures this column is sorted identically by the database and
golang, which should eliminate issues related to a mismatch in sort
order.

* chore: make test stricter

* fix: also add binary collation for postgres

pkg/services/ngalert/store/alert_rule_test.go

@@ -1516,11 +1516,9 @@ func TestIntegrationListAlertRulesByGroupCaseSensitiveOrdering(t *testing.T) {
 		}
 
 		// Verify case-sensitive alphabetical ordering
-		// different databases may sort uppercase before lowercase or vice versa depending on character set, the important part is that the order is consistent and case-sensitive
-		expectedOrder := []string{"test", "Test", "TEST"}
-		alternateExpectedOrder := []string{"TEST", "Test", "test"}
-		if !slices.Equal(groupOrder, expectedOrder) && !slices.Equal(groupOrder, alternateExpectedOrder) {
-			t.Fatalf("groups are not ordered case-sensitively as expected. got: %v, want: %v or %v", groupOrder, expectedOrder, alternateExpectedOrder)
+		expectedOrder := []string{"TEST", "Test", "test"}
+		if !slices.Equal(groupOrder, expectedOrder) {
+			t.Fatalf("groups are not ordered case-sensitively as expected. got: %v, want: %v", groupOrder, expectedOrder)
 		}
 
 		// Verify each group contains the correct rules

pkg/services/sqlstore/migrations/migrations.go

@@ -162,4 +162,6 @@ func (oss *OSSMigrations) AddMigration(mg *Migrator) {
 	ualert.ExpandAlertRuleUpdatedByMigration(mg)
 
 	ualert.AddAlertRuleGroupIndexMigration(mg)
+
+	ualert.CollateBinAlertRuleGroup(mg)
 }

pkg/services/sqlstore/migrations/ualert/alert_rule_group_collation_bin.go

@@ -0,0 +1,10 @@
+package ualert
+
+import "github.com/grafana/grafana/pkg/services/sqlstore/migrator"
+
+// CollateBinAlertRuleGroup ensures that rule_group column collates in the same way go sorts strings.
+func CollateBinAlertRuleGroup(mg *migrator.Migrator) {
+	mg.AddMigration("ensure rule_group column sorts the same way as golang", migrator.NewRawSQLMigration("").
+		Mysql("ALTER TABLE alert_rule MODIFY rule_group VARCHAR(190) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL;").
+		Postgres(`ALTER TABLE alert_rule ALTER COLUMN rule_group SET DATA TYPE varchar(190) COLLATE "C";`))
+}