Rc and Arc are missing new_cyclic_in #132
Comments
|
Yes, this does seem to be an oversight, feel free to make a PR. |
|
Great, I made a PR here: rust-lang/rust#129674. I have a few outstanding questions in that PR. If you wouldn't mind taking a look at that, it would be much appreciated. I'm very new to the standard library and don't know some of its conventions. |
|
Bump! Would love some feedback on if that PR is done appropriately. |
|
PR is still marked as "draft". |
|
Thank you, fixed! |
fee1-dead
added a commit
to fee1-dead-contrib/rust
that referenced
this issue
Sep 17, 2024
… r=dtolnay Add new_cyclic_in for Rc and Arc Currently, new_cyclic_in does not exist for Rc and Arc. This is an oversight according to rust-lang/wg-allocators#132. This PR adds new_cyclic_in for Rc and Arc. The implementation is almost the exact same as new_cyclic with some small differences to make it allocator-specific. new_cyclic's implementation has been replaced with a call to `new_cyclic_in(data_fn, Global)`. Remaining questions: * ~~Is requiring Allocator to be Clone OK? According to rust-lang/wg-allocators#88, Allocators should be cheap to clone. I'm just hesitant to add unnecessary constraints, though I don't see an obvious workaround for this function since many called functions in new_cyclic_in expect an owned Allocator. I see Allocator.by_ref() as an option, but that doesn't work on when creating Weak { ptr: init_ptr, alloc: alloc.clone() }, because the type of Weak then becomes Weak<T, &A> which is incompatible.~~ Fixed, thank you `@zakarumych!` This PR no longer requires the allocator to be Clone. * Currently, new_cyclic_in's documentation is almost entirely copy-pasted from new_cyclic, with minor tweaks to make it more accurate (e.g. Rc<T> -> Rc<T, A>). The example section is removed to mitigate redundancy and instead redirects to cyclic_in. Is this appropriate? * ~~The comments in new_cyclic_in (and much of the implementation) are also copy-pasted from new_cyclic. Would it be better to make a helper method new_cyclic_in_internal that both functions call, with either Global or the custom allocator? I'm not sure if that's even possible, since the internal method would have to return Arc<T, Global> and I don't know if it's possible to "downcast" that to an Arc<T>. Maybe transmute would work here?~~ Done, thanks `@zakarumych` * Arc::new_cyclic is #[inline], but Rc::new_cyclic is not. Which is preferred? * nit: does it matter where in the impl block new_cyclic_in is defined?
bors
added a commit
to rust-lang-ci/rust
that referenced
this issue
Sep 17, 2024
…=dtolnay Add new_cyclic_in for Rc and Arc Currently, new_cyclic_in does not exist for Rc and Arc. This is an oversight according to rust-lang/wg-allocators#132. This PR adds new_cyclic_in for Rc and Arc. The implementation is almost the exact same as new_cyclic with some small differences to make it allocator-specific. new_cyclic's implementation has been replaced with a call to `new_cyclic_in(data_fn, Global)`. Remaining questions: * ~~Is requiring Allocator to be Clone OK? According to rust-lang/wg-allocators#88, Allocators should be cheap to clone. I'm just hesitant to add unnecessary constraints, though I don't see an obvious workaround for this function since many called functions in new_cyclic_in expect an owned Allocator. I see Allocator.by_ref() as an option, but that doesn't work on when creating Weak { ptr: init_ptr, alloc: alloc.clone() }, because the type of Weak then becomes Weak<T, &A> which is incompatible.~~ Fixed, thank you `@zakarumych!` This PR no longer requires the allocator to be Clone. * Currently, new_cyclic_in's documentation is almost entirely copy-pasted from new_cyclic, with minor tweaks to make it more accurate (e.g. Rc<T> -> Rc<T, A>). The example section is removed to mitigate redundancy and instead redirects to cyclic_in. Is this appropriate? * ~~The comments in new_cyclic_in (and much of the implementation) are also copy-pasted from new_cyclic. Would it be better to make a helper method new_cyclic_in_internal that both functions call, with either Global or the custom allocator? I'm not sure if that's even possible, since the internal method would have to return Arc<T, Global> and I don't know if it's possible to "downcast" that to an Arc<T>. Maybe transmute would work here?~~ Done, thanks `@zakarumych` * Arc::new_cyclic is #[inline], but Rc::new_cyclic is not. Which is preferred? * nit: does it matter where in the impl block new_cyclic_in is defined?
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this issue
Sep 17, 2024
… r=dtolnay Add new_cyclic_in for Rc and Arc Currently, new_cyclic_in does not exist for Rc and Arc. This is an oversight according to rust-lang/wg-allocators#132. This PR adds new_cyclic_in for Rc and Arc. The implementation is almost the exact same as new_cyclic with some small differences to make it allocator-specific. new_cyclic's implementation has been replaced with a call to `new_cyclic_in(data_fn, Global)`. Remaining questions: * ~~Is requiring Allocator to be Clone OK? According to rust-lang/wg-allocators#88, Allocators should be cheap to clone. I'm just hesitant to add unnecessary constraints, though I don't see an obvious workaround for this function since many called functions in new_cyclic_in expect an owned Allocator. I see Allocator.by_ref() as an option, but that doesn't work on when creating Weak { ptr: init_ptr, alloc: alloc.clone() }, because the type of Weak then becomes Weak<T, &A> which is incompatible.~~ Fixed, thank you `@zakarumych!` This PR no longer requires the allocator to be Clone. * Currently, new_cyclic_in's documentation is almost entirely copy-pasted from new_cyclic, with minor tweaks to make it more accurate (e.g. Rc<T> -> Rc<T, A>). The example section is removed to mitigate redundancy and instead redirects to cyclic_in. Is this appropriate? * ~~The comments in new_cyclic_in (and much of the implementation) are also copy-pasted from new_cyclic. Would it be better to make a helper method new_cyclic_in_internal that both functions call, with either Global or the custom allocator? I'm not sure if that's even possible, since the internal method would have to return Arc<T, Global> and I don't know if it's possible to "downcast" that to an Arc<T>. Maybe transmute would work here?~~ Done, thanks `@zakarumych` * Arc::new_cyclic is #[inline], but Rc::new_cyclic is not. Which is preferred? * nit: does it matter where in the impl block new_cyclic_in is defined?
rust-timer
added a commit
to rust-lang-ci/rust
that referenced
this issue
Sep 17, 2024
Rollup merge of rust-lang#129674 - matthewpipie:rc-arc-new-cyclic-in, r=dtolnay Add new_cyclic_in for Rc and Arc Currently, new_cyclic_in does not exist for Rc and Arc. This is an oversight according to rust-lang/wg-allocators#132. This PR adds new_cyclic_in for Rc and Arc. The implementation is almost the exact same as new_cyclic with some small differences to make it allocator-specific. new_cyclic's implementation has been replaced with a call to `new_cyclic_in(data_fn, Global)`. Remaining questions: * ~~Is requiring Allocator to be Clone OK? According to rust-lang/wg-allocators#88, Allocators should be cheap to clone. I'm just hesitant to add unnecessary constraints, though I don't see an obvious workaround for this function since many called functions in new_cyclic_in expect an owned Allocator. I see Allocator.by_ref() as an option, but that doesn't work on when creating Weak { ptr: init_ptr, alloc: alloc.clone() }, because the type of Weak then becomes Weak<T, &A> which is incompatible.~~ Fixed, thank you `@zakarumych!` This PR no longer requires the allocator to be Clone. * Currently, new_cyclic_in's documentation is almost entirely copy-pasted from new_cyclic, with minor tweaks to make it more accurate (e.g. Rc<T> -> Rc<T, A>). The example section is removed to mitigate redundancy and instead redirects to cyclic_in. Is this appropriate? * ~~The comments in new_cyclic_in (and much of the implementation) are also copy-pasted from new_cyclic. Would it be better to make a helper method new_cyclic_in_internal that both functions call, with either Global or the custom allocator? I'm not sure if that's even possible, since the internal method would have to return Arc<T, Global> and I don't know if it's possible to "downcast" that to an Arc<T>. Maybe transmute would work here?~~ Done, thanks `@zakarumych` * Arc::new_cyclic is #[inline], but Rc::new_cyclic is not. Which is preferred? * nit: does it matter where in the impl block new_cyclic_in is defined?
|
Merged! |
RalfJung
pushed a commit
to RalfJung/miri
that referenced
this issue
Sep 21, 2024
Add new_cyclic_in for Rc and Arc Currently, new_cyclic_in does not exist for Rc and Arc. This is an oversight according to rust-lang/wg-allocators#132. This PR adds new_cyclic_in for Rc and Arc. The implementation is almost the exact same as new_cyclic with some small differences to make it allocator-specific. new_cyclic's implementation has been replaced with a call to `new_cyclic_in(data_fn, Global)`. Remaining questions: * ~~Is requiring Allocator to be Clone OK? According to rust-lang/wg-allocators#88, Allocators should be cheap to clone. I'm just hesitant to add unnecessary constraints, though I don't see an obvious workaround for this function since many called functions in new_cyclic_in expect an owned Allocator. I see Allocator.by_ref() as an option, but that doesn't work on when creating Weak { ptr: init_ptr, alloc: alloc.clone() }, because the type of Weak then becomes Weak<T, &A> which is incompatible.~~ Fixed, thank you `@zakarumych!` This PR no longer requires the allocator to be Clone. * Currently, new_cyclic_in's documentation is almost entirely copy-pasted from new_cyclic, with minor tweaks to make it more accurate (e.g. Rc<T> -> Rc<T, A>). The example section is removed to mitigate redundancy and instead redirects to cyclic_in. Is this appropriate? * ~~The comments in new_cyclic_in (and much of the implementation) are also copy-pasted from new_cyclic. Would it be better to make a helper method new_cyclic_in_internal that both functions call, with either Global or the custom allocator? I'm not sure if that's even possible, since the internal method would have to return Arc<T, Global> and I don't know if it's possible to "downcast" that to an Arc<T>. Maybe transmute would work here?~~ Done, thanks `@zakarumych` * Arc::new_cyclic is #[inline], but Rc::new_cyclic is not. Which is preferred? * nit: does it matter where in the impl block new_cyclic_in is defined?
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
new_cyclic was added in Rust 1.60 and allows users to create cyclic data structures without unsafe code; however, there is no equivalent new_cyclic_in. If this is an oversight, I'm happy to make a PR.
The text was updated successfully, but these errors were encountered: