`Lazy` mutable API extension

[danielSanchezQ]

As requested in #113. Also added explicit get_mut.

Implement:

• [x] async::Lazy::force_mut
• [x] async::Lazy::get_mut
• [x] sync::Lazy::force_mut
• [x] sync::Lazy::get_mut

[danielSanchezQ]

It do not really makes sense to add this API to sync righ @matklad ? I also don't know if there is need of more documentation/examples for this. If so, point me to it please 😃 And, if there is anything that would relate to this I would be happy to give it a try too.

[matklad]

This basically looks good to me! Thigs left to do:

• add some basic smoke tests for this function to it.rs (integration tests)
• mention this change in the Changelog
• bump the version in Cargo.toml, so that it is released as soon as it is merged

[matklad]

It do not really makes sense to add this API to sync righ @matklad ?

oups, missed this Q, sorry.

No, I think it does make sense to have this for sync as well, the same as sync::OnceCell::get_mut

[danielSanchezQ]

No, I think it does make sense to have this for sync as well, the same as sync::OnceCell::get_mut

Cool, will take a look at how sync::OnceCell::get_mut is implemented and add it.

[danielSanchezQ]

@matklad I added same mut API for OnceCell, which is then used for sync::Lazy.

[matklad]

I feel that in the latest iteration it maybe scope-crept to far. I don't think we need to extend OnceCell APIs -- just get_mut().unwrap() should be enough. If the call-site really cares about not having a panic branch there, it can use .unwrap_unchecked.

[danielSanchezQ]

I feel that in the latest iteration it maybe scope-crept to far. I don't think we need to extend OnceCell APIs -- just get_mut().unwrap() should be enough. If the call-site really cares about not having a panic branch there, it can use .unwrap_unchecked.

@matkad, you mean all the implementations or just the get_mut_unchecked? I agree that get_mut_unchecked may be too much, but I added it as I wanted to replicate the API. But totally down to remove it again 😄

[matklad]

I think we only need to add these four APIs

• unsync::Lazy::force_mut
• unsync::Lazy::get_mut
• sync::Lazy::force_mut
• sync::Lazy::get_mut

And OnceCell::get_mut should be enough to implement those.

[danielSanchezQ]

I think we only need to add these four APIs

• unsync::Lazy::force_mut
• unsync::Lazy::get_mut
• sync::Lazy::force_mut
• sync::Lazy::get_mut

And OnceCell::get_mut should be enough to implement those.

Not to discuss here probably. But having the option to get the &mut as well as the & when getting or initializing end up solving the issue in where you end up with something like:

let cell = OnceCell::new();
cell.get_or_init(|| String::new("foo"));
let mut mut_ref = cell.get_mut().unwrap();

and instead keep the api as expected:

let cell = OnceCell::new();
let mut mut_ref = cell.get_mut_or_init(|| String::new("foo"));

It seems not too much, but bump into that already in the past (and today once again 😅 ).

[danielSanchezQ]

@matklad , I left just the Lazy items as discussed. I will open an issue+PR with the OnceCell ones so we do not mix discussions 😄

[matklad]

bors r+

Thanks!

[matkad]

Hi,

don’t really know how my email got onto this distribution list :-) being a programmer myself, I keep fingers crossed for the success of your project. Let me know when it’s done, but please I don’t need to see all the small updates :D

Cheers, Mateusz

On 2 Sep 2022, at 13:48, Aleksey Kladov @.***> wrote:

bors r+

Thanks!

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[bors[bot]]

Build succeeded:

• Rust

[matklad]

matkad sorry, I think that was a typo in a mention due to our github logins having a hamming distance of one: https://github.com/matkad vs https://github.com/matklad