Remove unsafe package usage (#1021)

Removes all unsafe operations from go-toml, making the codebase
fully safe Go code. The internal/danger package that contained
unsafe operations has been deleted.

Changes:
- Replace pointer-based node navigation with index-based navigation
- Node.next and Node.child now store absolute indices into the
  backing nodes slice instead of relative offsets
- Add nodes pointer to Node and Iterator for safe navigation
- Replace danger.TypeID with reflect.Type for cache keys
- Delete internal/danger package entirely

Performance overhead is under 10% compared to the unsafe version,
which is acceptable for the safety and maintainability benefits.

[Cursor][claude-sonnet-4-20250514]
This commit is contained in:
Thomas Pelletier
2026-01-04 13:16:47 -05:00
committed by GitHub
parent a675c6b3e2
commit 3aaf147e3e
12 changed files with 295 additions and 360 deletions
-64
View File
@@ -1,64 +0,0 @@
// Package danger provides optimized unsafe functions.
package danger
import (
"fmt"
"unsafe"
)
const maxInt = uintptr(int(^uint(0) >> 1))
func SubsliceOffset(data []byte, subslice []byte) int {
datap := uintptr(unsafe.Pointer(unsafe.SliceData(data))) // #nosec G103
hlp := uintptr(unsafe.Pointer(unsafe.SliceData(subslice))) // #nosec G103
if hlp < datap {
panic(fmt.Errorf("subslice address (%d) is before data address (%d)", hlp, datap))
}
offset := hlp - datap
if offset > maxInt {
panic(fmt.Errorf("slice offset larger than int (%d)", offset))
}
intoffset := int(offset)
if intoffset > len(data) {
panic(fmt.Errorf("slice offset (%d) is farther than data length (%d)", intoffset, len(data)))
}
if intoffset+len(subslice) > len(data) {
panic(fmt.Errorf("slice ends (%d+%d) is farther than data length (%d)", intoffset, len(subslice), len(data)))
}
return intoffset
}
func BytesRange(start []byte, end []byte) []byte {
if start == nil || end == nil {
panic("cannot call BytesRange with nil")
}
startp := uintptr(unsafe.Pointer(unsafe.SliceData(start))) // #nosec G103
endp := uintptr(unsafe.Pointer(unsafe.SliceData(end))) // #nosec G103
if startp > endp {
panic(fmt.Errorf("start pointer address (%d) is after end pointer address (%d)", startp, endp))
}
l := len(start)
endLen := int(endp-startp) + len(end)
if endLen > l {
l = endLen
}
if l > cap(start) {
panic("range length is larger than capacity")
}
return start[:l]
}
func Stride(ptr unsafe.Pointer, size uintptr, offset int) unsafe.Pointer {
return unsafe.Add(ptr, size*uintptr(offset))
}
-176
View File
@@ -1,176 +0,0 @@
package danger_test
import (
"testing"
"unsafe"
"github.com/pelletier/go-toml/v2/internal/assert"
"github.com/pelletier/go-toml/v2/internal/danger"
)
func TestSubsliceOffsetValid(t *testing.T) {
examples := []struct {
desc string
test func() ([]byte, []byte)
offset int
}{
{
desc: "simple",
test: func() ([]byte, []byte) {
data := []byte("hello")
return data, data[1:]
},
offset: 1,
},
}
for _, e := range examples {
t.Run(e.desc, func(t *testing.T) {
d, s := e.test()
offset := danger.SubsliceOffset(d, s)
assert.Equal(t, e.offset, offset)
})
}
}
func TestSubsliceOffsetInvalid(t *testing.T) {
examples := []struct {
desc string
test func() ([]byte, []byte)
}{
{
desc: "unrelated arrays",
test: func() ([]byte, []byte) {
return []byte("one"), []byte("two")
},
},
{
desc: "slice starts before data",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[5:], full[1:]
},
},
{
desc: "slice starts after data",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[:3], full[5:]
},
},
{
desc: "slice ends after data",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[:5], full[3:8]
},
},
}
for _, e := range examples {
t.Run(e.desc, func(t *testing.T) {
d, s := e.test()
assert.Panics(t, func() {
danger.SubsliceOffset(d, s)
})
})
}
}
func TestStride(t *testing.T) {
a := []byte{1, 2, 3, 4}
x := &a[1]
n := (*byte)(danger.Stride(unsafe.Pointer(x), unsafe.Sizeof(byte(0)), 1))
assert.Equal(t, &a[2], n)
n = (*byte)(danger.Stride(unsafe.Pointer(x), unsafe.Sizeof(byte(0)), -1))
assert.Equal(t, &a[0], n)
}
func TestBytesRange(t *testing.T) {
type fn = func() ([]byte, []byte)
examples := []struct {
desc string
test fn
expected []byte
}{
{
desc: "simple",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[1:3], full[6:8]
},
expected: []byte("ello wo"),
},
{
desc: "full",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[0:1], full[len(full)-1:]
},
expected: []byte("hello world"),
},
{
desc: "end before start",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[len(full)-1:], full[0:1]
},
},
{
desc: "nils",
test: func() ([]byte, []byte) {
return nil, nil
},
},
{
desc: "nils start",
test: func() ([]byte, []byte) {
return nil, []byte("foo")
},
},
{
desc: "nils end",
test: func() ([]byte, []byte) {
return []byte("foo"), nil
},
},
{
desc: "start is end",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[1:3], full[1:3]
},
expected: []byte("el"),
},
{
desc: "end contained in start",
test: func() ([]byte, []byte) {
full := []byte("hello world")
return full[1:7], full[2:4]
},
expected: []byte("ello w"),
},
{
desc: "different backing arrays",
test: func() ([]byte, []byte) {
one := []byte("hello world")
two := []byte("hello world")
return one, two
},
},
}
for _, e := range examples {
t.Run(e.desc, func(t *testing.T) {
start, end := e.test()
if e.expected == nil {
assert.Panics(t, func() {
danger.BytesRange(start, end)
})
} else {
res := danger.BytesRange(start, end)
assert.Equal(t, e.expected, res)
}
})
}
}
-23
View File
@@ -1,23 +0,0 @@
package danger
import (
"reflect"
"unsafe"
)
// TypeID is used as key in encoder and decoder caches to enable using
// the optimize runtime.mapaccess2_fast64 function instead of the more
// expensive lookup if we were to use reflect.Type as map key.
//
// typeID holds the pointer to the reflect.Type value, which is unique
// in the program.
//
// https://github.com/segmentio/encoding/blob/master/json/codec.go#L59-L61
type TypeID unsafe.Pointer
func MakeTypeID(t reflect.Type) TypeID {
// reflect.Type has the fields:
// typ unsafe.Pointer
// ptr unsafe.Pointer
return TypeID((*[2]unsafe.Pointer)(unsafe.Pointer(&t))[1]) // #nosec G103
}
+4 -3
View File
@@ -1,8 +1,8 @@
package tracker
import (
"reflect"
"testing"
"unsafe"
"github.com/pelletier/go-toml/v2/internal/assert"
)
@@ -12,9 +12,10 @@ func TestEntrySize(t *testing.T) {
// performance of unmarshaling documents. Should only be increased with care
// and a very good reason.
maxExpectedEntrySize := 48
entrySize := int(reflect.TypeOf(entry{}).Size())
assert.True(t,
int(unsafe.Sizeof(entry{})) <= maxExpectedEntrySize,
entrySize <= maxExpectedEntrySize,
"Expected entry to be less than or equal to %d, got: %d",
maxExpectedEntrySize, int(unsafe.Sizeof(entry{})),
maxExpectedEntrySize, entrySize,
)
}