From 7b699d279b6b266a0d977c914b22907a42a636b0 Mon Sep 17 00:00:00 2001
From: sujal shah <sujalshah28092004@gmail.com>
Date: Thu, 16 Jan 2025 04:26:54 +0530
Subject: [PATCH] promql_parser: Fix invalid format return by `/format_query`.

Added `IsValidLegacy` to ensure UTF-8 labels
in MatchingLabels and Include are properly quoted. Updated
getMatchingStr to use quoted labels for correct formatting in
returned expressions.

Fixes #15243.

Signed-off-by: sujal shah <sujalshah28092004@gmail.com>
---
 promql/parser/printer.go | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/promql/parser/printer.go b/promql/parser/printer.go
index afe755e7dd..02dde452ee 100644
--- a/promql/parser/printer.go
+++ b/promql/parser/printer.go
@@ -100,7 +100,7 @@ func joinLabels(ss []string) string {
 		if i > 0 {
 			b.WriteString(", ")
 		}
-		if !model.IsValidLegacyMetricName(string(model.LabelValue(s))) {
+		if !model.LabelName(s).IsValidLegacy() {
 			b.Write(strconv.AppendQuote(b.AvailableBuffer(), s))
 		} else {
 			b.WriteString(s)
@@ -128,19 +128,24 @@ func (node *BinaryExpr) ShortString() string {
 func (node *BinaryExpr) getMatchingStr() string {
 	matching := ""
 	vm := node.VectorMatching
-	if vm != nil && (len(vm.MatchingLabels) > 0 || vm.On) {
-		vmTag := "ignoring"
-		if vm.On {
-			vmTag = "on"
-		}
-		matching = fmt.Sprintf(" %s (%s)", vmTag, strings.Join(vm.MatchingLabels, ", "))
-
-		if vm.Card == CardManyToOne || vm.Card == CardOneToMany {
-			vmCard := "right"
-			if vm.Card == CardManyToOne {
-				vmCard = "left"
+	if vm != nil {
+		if len(vm.MatchingLabels) > 0 || vm.On {
+			vmTag := "ignoring"
+			if vm.On {
+				vmTag = "on"
+			}
+			// Quote only necessary labels.
+			matching = fmt.Sprintf(" %s (%s)", vmTag, joinLabels(vm.MatchingLabels))
+
+			if vm.Card == CardManyToOne || vm.Card == CardOneToMany {
+				vmCard := "right"
+				if vm.Card == CardManyToOne {
+					vmCard = "left"
+				}
+				// Quote only necessary Include labels.
+				matching += fmt.Sprintf(" group_%s (%s)", vmCard, joinLabels(vm.Include))
+				fmt.Printf("\n")
 			}
-			matching += fmt.Sprintf(" group_%s (%s)", vmCard, strings.Join(vm.Include, ", "))
 		}
 	}
 	return matching