fix: Fixed the issue of missing cap when StringToBytes returns result (#306)

Co-authored-by: 燕归来 <dylan@infinni.io>

strutil/string.go

@@ -396,7 +396,10 @@ func RemoveNonPrintable(str string) string {
 // StringToBytes converts a string to byte slice without a memory allocation.
 // Play: https://go.dev/play/p/7OyFBrf9AxA
 func StringToBytes(str string) (b []byte) {
-	return *(*[]byte)(unsafe.Pointer(&str))
+	return *(*[]byte)(unsafe.Pointer(&struct {
+		string
+		Cap int
+	}{str, len(str)}))
 }
 
 // BytesToString converts a byte slice to string without a memory allocation.

strutil/string_test.go

@@ -518,7 +518,8 @@ func TestStringToBytes(t *testing.T) {
 	assert := internal.NewAssert(t, "TestStringToBytes")
 
 	bytes := StringToBytes("abc")
-	assert.Equal(bytes, []byte{'a', 'b', 'c'})
+	assert.Equal([]byte{'a', 'b', 'c'}, bytes)
+	assert.Equal(3, cap(bytes))
 }
 
 func TestBytesToString(t *testing.T) {