[Dylan16807]

"uses more memory than what's efficient"

There is a hidden memory store using orders of magnitude more RAM than the live data. Why do we need to nitpick exactly how hidden it is? Are you going to be mad if I don't know whether it's literally inaccessible or not?

[nemothekid]

Because there are legitimate reasons why memory can be allocated. This is like calling your OS cache a memory leak when you open up Task Manager and see you only have 400MB free. A memory leak implies memory that is lost for good and it no longer being kept track of.

Consider it this way - if I had a program that connected to a database and used a connection pool to improve performance, would it be a "connection leak" that 5 connections were opened even though the database was idle?

The framing here is similar - Rust, in an attempt to improve performance reused large memory allocations. Some applications do this on purpose and call it buffer pools.

[Dylan16807]

Except this memory is not being intentionally used as a cache/buffer.

Rust attempts to keep the vector capacity in a range for that purpose, and failed to do so here.

No matter what, it's a bug. So none of those possible justifications fit, because it's a bug.

For the database analogy, I would call it a connection leak if the number of idle connections greatly exceeded the amount that had ever been simultaneously busy and they weren't actually getting reused.