Unobserved Append
ID |
go.unobserved_append |
Severity |
high |
Remediation Complexity |
trivial |
Remediation Risk |
low |
Remediation Effort |
low |
Resource |
Reliability |
Language |
Go |
Tags |
reliability, suspicious |
Description
Reports a bare append(s, x) call whose result is discarded — the call is a statement on its
own and is not assigned to anything.
Rationale
append may grow the slice into a freshly allocated backing array and always returns a slice
header whose length reflects the appended elements. The returned value is the only reliable way
to observe the result. When the return value is dropped, the appended element is silently lost
(or the caller keeps using a stale, shorter slice) — almost always a forgotten assignment.
// Bad
append(s, 1) // FLAW — the grown slice is thrown away
// Good
s = append(s, 1) // OK — result assigned back
t := append(s, 1) // OK — result capturedRemediation
Assign the result of append back to the slice variable (s = append(s, x)) or capture it in a
new variable.