tpl: Fix panic in pairList.Less

While sorting on data sources with missing fields, a panic can occur in
pairList.Less if `Interface()` is called on a invalid `reflect.Value`.
This commit detects an invalid Value and replacing it with a zero value
for the comparison.
This commit is contained in:
Cameron Moore 2016-03-29 20:50:54 -05:00 committed by Bjørn Erik Pedersen
parent 7d5c9fbf44
commit d15fda5000
2 changed files with 33 additions and 1 deletions

View file

@ -1054,7 +1054,24 @@ type pairList struct {
func (p pairList) Swap(i, j int) { p.Pairs[i], p.Pairs[j] = p.Pairs[j], p.Pairs[i] }
func (p pairList) Len() int { return len(p.Pairs) }
func (p pairList) Less(i, j int) bool {
return lt(p.Pairs[i].SortByValue.Interface(), p.Pairs[j].SortByValue.Interface())
iv := p.Pairs[i].SortByValue
jv := p.Pairs[j].SortByValue
if iv.IsValid() {
if jv.IsValid() {
// can only call Interface() on valid reflect Values
return lt(iv.Interface(), jv.Interface())
}
// if j is invalid, test i against i's zero value
return lt(iv.Interface(), reflect.Zero(iv.Type()))
}
if jv.IsValid() {
// if i is invalid, test j against j's zero value
return lt(reflect.Zero(jv.Type()), jv.Interface())
}
return false
}
// sorts a pairList and returns a slice of sorted values

View file

@ -1535,6 +1535,21 @@ func TestSort(t *testing.T) {
"asc",
[]map[string]mid{{"foo": mid{Tst: TstX{A: "a", B: "b"}}}, {"foo": mid{Tst: TstX{A: "c", B: "d"}}}, {"foo": mid{Tst: TstX{A: "e", B: "f"}}}},
},
// interface slice with missing elements
{
[]interface{}{
map[interface{}]interface{}{"Title": "Foo", "Weight": 10},
map[interface{}]interface{}{"Title": "Bar"},
map[interface{}]interface{}{"Title": "Zap", "Weight": 5},
},
"Weight",
"asc",
[]interface{}{
map[interface{}]interface{}{"Title": "Bar"},
map[interface{}]interface{}{"Title": "Zap", "Weight": 5},
map[interface{}]interface{}{"Title": "Foo", "Weight": 10},
},
},
// test error cases
{(*[]TstX)(nil), nil, "asc", false},
{TstX{A: "a", B: "b"}, nil, "asc", false},