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Merge pull request #12145 from bboreham/fix-label-builder 

labels: cope with mutating Builder during Range call
pull/11900/head
Bartlomiej Plotka 2023-03-16 19:33:14 +01:00 committed by GitHub
parent d303fa77b9 3743d87c56
commit a494c44746
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 24 additions and 5 deletions
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7
model/labels/labels.go
View File

@ -545,9 +545,12 @@ func (b *Builder) Get(n string) string {
}
// Range calls f on each label in the Builder.
// If f calls Set or Del on b then this may affect what callbacks subsequently happen.
func (b *Builder) Range(f func(l Label)) {
origAdd, origDel := b.add, b.del
// Stack-based arrays to avoid heap allocation in most cases.
var addStack [1024]Label
var delStack [1024]string
// Take a copy of add and del, so they are unaffected by calls to Set() or Del().
origAdd, origDel := append(addStack[:0], b.add...), append(delStack[:0], b.del...)
b.base.Range(func(l Label) {
if !slices.Contains(origDel, l.Name) && !contains(origAdd, l.Name) {
f(l)

7
model/labels/labels_string.go
View File

@ -599,9 +599,12 @@ func (b *Builder) Get(n string) string {
}
// Range calls f on each label in the Builder.
// If f calls Set or Del on b then this may affect what callbacks subsequently happen.
func (b *Builder) Range(f func(l Label)) {
origAdd, origDel := b.add, b.del
// Stack-based arrays to avoid heap allocation in most cases.
var addStack [1024]Label
var delStack [1024]string
// Take a copy of add and del, so they are unaffected by calls to Set() or Del().
origAdd, origDel := append(addStack[:0], b.add...), append(delStack[:0], b.del...)
b.base.Range(func(l Label) {
if !slices.Contains(origDel, l.Name) && !contains(origAdd, l.Name) {
f(l)

15
model/labels/labels_test.go
View File

@ -529,6 +529,11 @@ func TestBuilder(t *testing.T) {
base: FromStrings("aaa", "111"),
want: FromStrings("aaa", "111"),
},
{
base: FromStrings("aaa", "111", "bbb", "222", "ccc", "333"),
set: []Label{{"aaa", "444"}, {"bbb", "555"}, {"ccc", "666"}},
want: FromStrings("aaa", "444", "bbb", "555", "ccc", "666"),
},
{
base: FromStrings("aaa", "111", "bbb", "222", "ccc", "333"),
del: []string{"bbb"},
@ -591,7 +596,15 @@ func TestBuilder(t *testing.T) {
b.Keep(tcase.keep...)
}
b.Del(tcase.del...)
require.Equal(t, tcase.want, b.Labels(tcase.base))
require.Equal(t, tcase.want, b.Labels(EmptyLabels()))
// Check what happens when we call Range and mutate the builder.
b.Range(func(l Label) {
if l.Name == "aaa" || l.Name == "bbb" {
b.Del(l.Name)
}
})
require.Equal(t, tcase.want.BytesWithoutLabels(nil, "aaa", "bbb"), b.Labels(tcase.base).Bytes(nil))
})
}
}