bump minimum hash brown version to 0.15

[joseluis]

Bug Description

There's a combination of dependencies and features that fails to compile, due to the minimum version for the hashbrown crate.

The easiest solution is to bump hashbrown versioning from ">= 0.14.5, < 0.16". to ">= 0.15.0, < 0.16" (fortunately 0.15.0 has the same MSRV of 1.63.0 as pyo3 does).

Steps to Reproduce

1. create a new cargo project with this manifest:

Cargo.toml

[package]
name = "pyo3-hashbrown-nightly"
version = "0.1.0"
edition = "2021"

[dependencies]
hashbrown = {version = "0.15", features = ["nightly"] }
pyo3 = { version = "0.23.4", features = ["hashbrown"] }

2. run:

cargo +nightly update -Z minimal-versions
cargo +nightly build

Backtrace

Your operating system and version

linux 5.15

Your Python version (python --version)

Python 3.10.12

Your Rust version (rustc --version)

rustc 1.86.0-nightly (2f348cb7c 2025-01-27)

Your PyO3 version

0.23.4

How did you install python? Did you use a virtualenv?

n/a

Additional Info

No response

[davidhewitt]

Sorry for the slow reply. So it looks like according to rust-lang/hashbrown#574 (comment) we might be able to bump to 0.15 with some work.