Common Slice Gotchas in Go

Shared backing arrays cause memory leaks when slice functions like slices.Delete or slices.Compact leave old pointers in the underlying array beyond the new length. Always assign the return value of these functions to update the slice header and ensure the garbage collector can reclaim the memory.

s = slices.Delete(s, 2, 5)

Ignoring the return value leaves the original slice pointing to the modified array with stale pointers, preventing garbage collection of the deleted elements.

Slices are just views of a larger array. When you delete items from a slice, the old data often stays in that array, keeping memory alive even if you think you removed it. You must capture the new slice returned by the function to tell Go exactly which part of the array is still in use.