Fix potential deadlock in ByParam

Fixes gohugoio#11039

langs/language.go

@@ -181,3 +181,14 @@ type Collator struct {
 func (c *Collator) CompareStrings(a, b string) int {
 	return c.c.CompareString(a, b)
 }
+
+// CompareStrings compares a and b using the Collator in l.
+// It returns -1 if a < b, 1 if a > b and 0 if a == b.
+// Note that the Collator is not thread safe, so you may want
+// to acquire a lock on it before calling this method.
+func CompareStrings(l *Language, a, b string) int {
+	l.collator.Lock()
+	defer l.collator.Unlock()
+	return l.collator.CompareStrings(a, b)
+
+}

resources/page/pages_sort.go

@@ -372,9 +372,6 @@ func (p Pages) ByParam(paramsKey any) Pages {
 	paramsKeyStr := cast.ToString(paramsKey)
 	key := "pageSort.ByParam." + paramsKeyStr
 
-	stringLess, close := collatorStringLess(p[0])
-	defer close()
-
 	paramsKeyComparator := func(p1, p2 Page) bool {
 		v1, _ := p1.Param(paramsKeyStr)
 		v2, _ := p2.Param(paramsKeyStr)
@@ -403,7 +400,8 @@ func (p Pages) ByParam(paramsKey any) Pages {
 		s1 := cast.ToString(v1)
 		s2 := cast.ToString(v2)
 
-		return stringLess(s1, s2)
+		// Hold the lock as short as possible, see #11039.
+		return langs.CompareStrings(p1.CurrentSection().Language(), s1, s2) < 0
 
 	}