Limit intstr.Parse() to 32-bit integer parsing

Currently, intstr.Parse() attempts to parse its input using
strconv.Atoi(); if that succeeds, it stores the result using
FromInt(). This means that integer values which fit in int but not in
int32 end up corrupted, even though IntOrString can store them
correctly (as a string).

This changes intstr.Parse() to use strconv.ParseInt(), limiting the
input size to 32 bits. Thus values larger than that are stored
correctly using a string.

Signed-off-by: Stephen Kitt <skitt@redhat.com>

staging/src/k8s.io/apimachinery/pkg/util/intstr/intstr_test.go

@@ -264,3 +264,63 @@ func TestGetValueFromIntOrPercentNil(t *testing.T) {
 		t.Errorf("expected error got none")
 	}
 }
+
+func TestParse(t *testing.T) {
+	tests := []struct {
+		input  string
+		output IntOrString
+	}{
+		{
+			input:  "0",
+			output: IntOrString{Type: Int, IntVal: 0},
+		},
+		{
+			input:  "2147483647", // math.MaxInt32
+			output: IntOrString{Type: Int, IntVal: 2147483647},
+		},
+		{
+			input:  "-2147483648", // math.MinInt32
+			output: IntOrString{Type: Int, IntVal: -2147483648},
+		},
+		{
+			input:  "2147483648", // math.MaxInt32+1
+			output: IntOrString{Type: String, StrVal: "2147483648"},
+		},
+		{
+			input:  "-2147483649", // math.MinInt32-1
+			output: IntOrString{Type: String, StrVal: "-2147483649"},
+		},
+		{
+			input:  "9223372036854775807", // math.MaxInt64
+			output: IntOrString{Type: String, StrVal: "9223372036854775807"},
+		},
+		{
+			input:  "-9223372036854775808", // math.MinInt64
+			output: IntOrString{Type: String, StrVal: "-9223372036854775808"},
+		},
+		{
+			input:  "9223372036854775808", // math.MaxInt64+1
+			output: IntOrString{Type: String, StrVal: "9223372036854775808"},
+		},
+		{
+			input:  "-9223372036854775809", // math.MinInt64-1
+			output: IntOrString{Type: String, StrVal: "-9223372036854775809"},
+		},
+	}
+
+	for i, test := range tests {
+		t.Logf("test case %d", i)
+		value := Parse(test.input)
+		if test.output.Type != value.Type {
+			t.Errorf("expected type %d (%v), but got %d (%v)", test.output.Type, test.output, value.Type, value)
+			continue
+		}
+		if value.Type == Int && test.output.IntVal != value.IntVal {
+			t.Errorf("expected int value %d (%v), but got %d (%v)", test.output.IntVal, test.output, value.IntVal, value)
+			continue
+		}
+		if value.Type == String && test.output.StrVal != value.StrVal {
+			t.Errorf("expected string value %q (%v), but got %q (%v)", test.output.StrVal, test.output, value.StrVal, value)
+		}
+	}
+}