append possibly assigns to a wrong variable CRT-D0001
Bug risk
Minor
6 months ago
—
a year old
append result not assigned to the same slice
61 if len(lines) > h.maxSize {
62 lines = lines[len(lines)-h.maxSize:]
63 }
64 h.lines = append(lines, "")65 return ioutil.WriteFile(h.path, []byte(strings.Join(h.lines, "\n")), 0600)
66}
67append result not assigned to the same slice
57 return nil
58 }
59
60 lines := append(h.lines[:len(h.lines)-1], line)61 if len(lines) > h.maxSize {
62 lines = lines[len(lines)-h.maxSize:]
63 }
Description
The builtin function append returns the updated slice after the append operation.
This resulting slice is usually assigned back to the same variable that contained
the original slice to which new values were appended.
Bad practice
x = []int{1, 3, 5}
append(x, 7) // returns the value []int{1, 3, 5, 7}. This is usually assigned back to x
x := []int{}
y := []int{}
x = append(y, 1) // possibly wrong
Recommended
x = []int{1, 3, 5}
x = append(x, 7)
x := []int{}
y := []int{}
y = append(y, 1) // append 1 to y