Which version of MSRV should be next?

[koushiro]

The current MSRV is 1.75, but when I want to use stabilized std::sync::LazyLock instead of once_cell::sync::Lazy in #5252 , I need to upgrade MSRV to 1.80.

@Xuanwo suggests that it'd be better to start a discussion to gather community feedback before upgrading the MSRV,
so can I upgrade MSRV to 1.80 in the next minor version of opendal core?
Or does anyone need a newer version?

[Xuanwo]

Top reverse dependencies of opendal: https://crates.io/crates/opendal/reverse_dependencies

• sccache: 1.75 (we can upgrade it first)
• zino-core: 1.80
• dragonfly-client-core: not specified
• zarrs: 1.76
• orc-rust: 1.73 (hide in feature gate)
• iceberg: 1.77.1
• rustic_backend: 1.76

Upgrading to 1.80 just for LazyLock doesn't seem like a strong enough reason right now.

[simonsan]

Could be nice, to have a discussion once, about the MSRV policy, so there doesn't need to be a lot of future discussion about it. Something for the Readme, maybe:

Minimum Rust version policy

This crate's minimum supported rustc version is 1.75.0.

The current policy is that the minimum Rust version required to use this crate
can be increased in minor version updates. For example, if crate 1.0 requires
Rust 1.20.0, then crate 1.0.z for all values of z will also require Rust
1.20.0 or newer. However, crate 1.y for y > 0 may require a newer minimum
version of Rust.

Also keep in mind for such a foundational crate like opendal a relatively recent version like one from July 25, 2024 (1.80.0), is quite a hard requirement for the ecosystem around it.

[koushiro]

Considering that 1.75 was released at the end of last year (Dec. 28, 2023), I don't think it's a very hard requirement.

[koushiro]

So before the release of version 1.0, does the opendal community currently have a specific MSRV upgrade strategy?
Maybe we can discuss it here and make a specific rule?

For example, the MSRV of the latest version of opendal (only used for 0.x versions) will be several versions ahead of the latest version of rust.

[Xuanwo]

Here is the data: https://p.datadoghq.com/sb/3a172e20-e9e1-11ed-80e3-da7ad0900002-973f4c1011257befa8598303217bfe3a?fromUser=false&refresh_mode=sliding&from_ts=1729695043384&to_ts=1730299843384&live=true

[Xuanwo]

[Xuanwo]

So our discussion turned into this problem: how many users do we want to support?

At current time (2024-10-30):

• 1.82: 13.56%
• 1.81: 66.73%
• 1.80: 76.79%
• 1.79: 83.03%
• 1.78: 86.44%
• 1.77: 88.04%
• 1.76: 89.83%
• 1.75: 92.75% (our current MSRV)

In order word:

• Raise to 1.76 -> -2.92%
• Raise to 1.77 -> -4.71%
• Raise to 1.78 -> -6.31%
• Raise to 1.79 -> -9.72%
• Raise to 1.80 -> -16.60%
• Raise to 1.81 -> -26.02%
• Raise to 1.82 -> -79.18%

[Xuanwo]

While reviewing this data, please note that not all users are using opendal; this is just one perspective.

[Xuanwo]

Proposed an RFC for this: #5256