tpl/math: Add MaxInt64 function

Closes #13693

tpl/math/init.go

@@ -115,6 +115,13 @@ func init() {
 			},
 		)
 
+		ns.AddMethodMapping(ctx.MaxInt64,
+			nil,
+			[][2]string{
+				{"{{ math.MaxInt64 }}", "9223372036854775807"},
+			},
+		)
+
 		ns.AddMethodMapping(ctx.Min,
 			nil,
 			[][2]string{

tpl/math/math.go

@@ -147,6 +147,11 @@ func (ns *Namespace) Max(inputs ...any) (maximum float64, err error) {
 	return ns.applyOpToScalarsOrSlices("Max", math.Max, inputs...)
 }
 
+// MaxInt64 returns the maximum value for a signed 64-bit integer.
+func (ns *Namespace) MaxInt64() int64 {
+	return math.MaxInt64
+}
+
 // Min returns the smaller of all numbers in inputs. Any slices in inputs are flattened.
 func (ns *Namespace) Min(inputs ...any) (minimum float64, err error) {
 	return ns.applyOpToScalarsOrSlices("Min", math.Min, inputs...)

tpl/math/math_test.go

@@ -879,3 +879,14 @@ func TestToRadians(t *testing.T) {
 		c.Assert(result, qt.Equals, test.expect)
 	}
 }
+
+func TestMaxInt64(t *testing.T) {
+	t.Parallel()
+	ns := New(nil)
+
+	var want int64 = 9223372036854775807
+	got := ns.MaxInt64()
+	if want != got {
+		t.Errorf("want %d, got %d", want, got)
+	}
+}