Document non-guarantees for Hash by the8472 · Pull Request #90995

Document non-guarantees for Hash by the8472 · Pull Request #90995 · rust-lang/rust

Dependence on endianness and type sizes was reported for enum discriminants in rust-lang#74215 but it is a more general
issue since for example the default implementation of `Hasher::write_usize` uses native endianness.
Additionally the implementations of library types are occasionally changed as their internal fields
change or hashing gets optimized.

added the T-libs-api

Relevant to the library API team, which will review and decide on the PR/issue.

label

Nov 18, 2021

Co-authored-by: pierwill <19642016+pierwill@users.noreply.github.com>

bors added S-waiting-on-bors

Status: Waiting on bors to run and complete tests. Bors will change the label on completion.

and removed S-waiting-on-review

Status: Awaiting review from the assignee but also interested parties.

labels

Nov 26, 2021

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Nov 27, 2021

Document non-guarantees for Hash

Dependence on endianness and type sizes was reported for enum discriminants in rust-lang#74215 but it is a more general
issue since for example the default implementation of `Hasher::write_usize` uses native endianness.
Additionally the implementations of library types are occasionally changed as their internal fields
change or hashing gets optimized.

## Question

Should this go on the module level documentation instead since it also concerns `Hasher` to some extent and not just `Hash`?

resolves rust-lang#74215

This was referenced

Nov 27, 2021

bors added a commit to rust-lang-ci/rust that referenced this pull request

Nov 27, 2021

…askrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#83791 (Weaken guarantee around advancing underlying iterators in zip)
 - rust-lang#90995 (Document non-guarantees for Hash)
 - rust-lang#91057 (Expand `available_parallelism` docs in anticipation of cgroup quota support)
 - rust-lang#91062 (rustdoc: Consolidate static-file replacement mechanism)
 - rust-lang#91208 (Account for incorrect `where T::Assoc = Ty` bound)
 - rust-lang#91266 (Use non-generic inner function for pointer formatting)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup