diff options
| -rw-r--r-- | src/runtime/slice.go | 4 | ||||
| -rw-r--r-- | test/fixedbugs/issue10135.go | 25 |
2 files changed, 28 insertions, 1 deletions
diff --git a/src/runtime/slice.go b/src/runtime/slice.go index 171087d7f6..f457f41429 100644 --- a/src/runtime/slice.go +++ b/src/runtime/slice.go @@ -53,7 +53,9 @@ func growslice(t *slicetype, old sliceStruct, n int64) sliceStruct { et := t.elem if et.size == 0 { - return sliceStruct{old.array, old.len, cap} + // append should not create a slice with nil pointer but non-zero len. + // We assume that append doesn't need to preserve old.array in this case. + return sliceStruct{unsafe.Pointer(&zerobase), old.len, cap} } newcap := old.cap diff --git a/test/fixedbugs/issue10135.go b/test/fixedbugs/issue10135.go new file mode 100644 index 0000000000..9985e5a0ee --- /dev/null +++ b/test/fixedbugs/issue10135.go @@ -0,0 +1,25 @@ +// run + +// Copyright 2015 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Issue 10135: append a slice with zero-sized element used +// to always return a slice with the same data pointer as the +// old slice, even if it's nil, so this program used to panic +// with nil pointer dereference because after append, s is a +// slice with nil data pointer but non-zero len and cap. + +package main + +type empty struct{} + +func main() { + var s []empty + + s = append(s, empty{}) + + for _, v := range s { + _ = v + } +} |