remove unknown nightly feature 'const_ptr_offset' #22

tsatke · 2022-03-28T06:51:58Z

This seems to let it build again.

Seems related to rust-lang/rust#71499 and rust-lang/rust#93957

josephlr

@phil-opp this also fixes some build failures for the x86_64 crate. See https://github.com/rust-osdev/x86_64/runs/5715700359

phil-opp · 2022-03-28T10:26:37Z

Thanks a lot!

phil-opp · 2022-03-28T10:33:41Z

Published as v0.2.17

Problem statement: An error will be reported after the uart version is updated: error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:28:36 | 28 | int_en: AtomicPtr::new(base_pointer.add(1)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:29:39 | 29 | fifo_ctrl: AtomicPtr::new(base_pointer.add(2)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:30:39 | 30 | line_ctrl: AtomicPtr::new(base_pointer.add(3)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:31:40 | 31 | modem_ctrl: AtomicPtr::new(base_pointer.add(4)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:32:38 | 32 | line_sts: AtomicPtr::new(base_pointer.add(5)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: could not compile `uart_16550` due to 5 previous errors Investigation: uart_16550 update - Remove stabilized nightly feature 'const_ptr_offset' ([confidential-containers#22](rust-osdev/uart_16550#22)) Solution: fixed uart_16550 version to 0.2.14 Signed-off-by: haowei <WeiX.Hao@intel.com>

Problem statement: An error will be reported after the uart version is updated: error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:28:36 | 28 | int_en: AtomicPtr::new(base_pointer.add(1)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:29:39 | 29 | fifo_ctrl: AtomicPtr::new(base_pointer.add(2)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:30:39 | 30 | line_ctrl: AtomicPtr::new(base_pointer.add(3)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:31:40 | 31 | modem_ctrl: AtomicPtr::new(base_pointer.add(4)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:32:38 | 32 | line_sts: AtomicPtr::new(base_pointer.add(5)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: could not compile `uart_16550` due to 5 previous errors Investigation + root cause: View recent updates to uart_16550 uart_16550 updated. - Remove stabilized nightly feature 'const_ptr_offset' ([confidential-containers#22](rust-osdev/uart_16550#22)) Solution: fixed uart_16550 version to 0.2.14 Signed-off-by: haowei <WeiX.Hao@intel.com>

Problem statement: An error will be reported after the uart version is updated: error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:28:36 | 28 | int_en: AtomicPtr::new(base_pointer.add(1)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:29:39 | 29 | fifo_ctrl: AtomicPtr::new(base_pointer.add(2)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:30:39 | 30 | line_ctrl: AtomicPtr::new(base_pointer.add(3)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:31:40 | 31 | modem_ctrl: AtomicPtr::new(base_pointer.add(4)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:32:38 | 32 | line_sts: AtomicPtr::new(base_pointer.add(5)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: could not compile `uart_16550` due to 5 previous errors Investigation + root cause: View recent updates to uart_16550 uart_16550 updated. - Remove stabilized nightly feature 'const_ptr_offset' ([#22](rust-osdev/uart_16550#22)) Solution: fixed uart_16550 version to 0.2.14 Signed-off-by: haowei <WeiX.Hao@intel.com>

Problem statement: An error will be reported after the uart version is updated: error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:28:36 | 28 | int_en: AtomicPtr::new(base_pointer.add(1)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:29:39 | 29 | fifo_ctrl: AtomicPtr::new(base_pointer.add(2)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:30:39 | 30 | line_ctrl: AtomicPtr::new(base_pointer.add(3)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:31:40 | 31 | modem_ctrl: AtomicPtr::new(base_pointer.add(4)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:32:38 | 32 | line_sts: AtomicPtr::new(base_pointer.add(5)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: could not compile `uart_16550` due to 5 previous errors Investigation + root cause: View recent updates to uart_16550 uart_16550 updated. - Remove stabilized nightly feature 'const_ptr_offset' ([confidential-containers#22](rust-osdev/uart_16550#22)) Solution: fixed uart_16550 version to 0.2.14 Signed-off-by: haowei <WeiX.Hao@intel.com>

Problem statement: An error will be reported after the uart version is updated: error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:28:36 | 28 | int_en: AtomicPtr::new(base_pointer.add(1)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:29:39 | 29 | fifo_ctrl: AtomicPtr::new(base_pointer.add(2)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:30:39 | 30 | line_ctrl: AtomicPtr::new(base_pointer.add(3)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:31:40 | 31 | modem_ctrl: AtomicPtr::new(base_pointer.add(4)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: `ptr::mut_ptr::<impl *mut T>::add` is not yet stable as a const fn --> /home/runner/.cargo/registry/src/gh.neting.cc-1ecc6299db9ec823/uart_16550-0.2.17/src/mmio.rs:32:38 | 32 | line_sts: AtomicPtr::new(base_pointer.add(5)), | ^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(const_ptr_offset)]` to the crate attributes to enable error: could not compile `uart_16550` due to 5 previous errors Investigation + root cause: View recent updates to uart_16550 uart_16550 updated. - Remove stabilized nightly feature 'const_ptr_offset' ([#22](rust-osdev/uart_16550#22)) Solution: fixed uart_16550 version to 0.2.14 Signed-off-by: haowei <WeiX.Hao@intel.com>

phip1611 · 2022-07-24T12:25:42Z

I am aware of that people break builds with feature updates (0.x.y) from time to time (especially if major is still 0) but breaking builds in bugfix updates is a bit.. unexpected. This broke my builds :)

josephlr · 2022-07-24T12:59:28Z

This change was a necessary bugfix to allow this crate to continue building on the latest nightly. Without this change, the crate would no longer compile.

Im confused how this actually broke you though. This change should be fine on older rustc versions. What specific compiler error are you getting? What version of rustc are you using? Are you using version 0.2.18 of this crate?

phip1611 · 2022-07-24T13:05:10Z

This change was a necessary bugfix to allow this crate to continue building on the latest nightly. Without this change, the crate would no longer compile.

Ah okay, I see. Well, this is my project respectively the fix: phip1611/diplomarbeit-impl@7296fbc It's on 1.61 nightly. I could fix this by pinning version 0.2.16.

phil-opp · 2022-07-24T15:48:47Z

Changed feature gates are the main difficulty of maintaining crates that target nightly Rust. Often, there is no way to keep supporting older nightly versions in such cases. In this case, the older nightlies expect the feature gate, but the newer ones throw an error because the feature gate no longer exists (since the feature was stabilized).

We had a lot of similar cases for the x86_64 crate and decided to resolve it by supporting only the latest nightly. Under this policy, we don't consider updating/removing feature gates as breaking changes because it effectively fixes a compile error.

The main reason for doing only patch releases as opposed to changing the minor version are transitive dependencies. For example, if we did a minor version bump for each feature gate update in x86_64, all dependent (library) crates would require a new release as well since cargo update only updates the patch version for v0.x.y crates. Coordinating this across different crates maintained by different people was a lot of effort and led to much more breakage. Because of this, we decided to consider such updates as bugfixes from then on and that policy worked much better.

That being said, it might be possible to continue supporting older nightlies through cfg attributes depending on the nightly version. However, I'm not sure if this is worth the effort. It would only work in certain cases and we don't want to increase the maintenance burden too much. Moving the crates to stable Rust as soon as possible seems like the better solution.

phip1611 · 2022-07-24T17:49:32Z

Yeah, I agree. The longer I think about it, the more your approach makes sense. That's what people have to expect when working on nightly Rust.

through cfg attributes depending on the nightly

Probably overkill, as long as the lib doesn't have 100k active users :D

remove unknown nightly feature 'const_ptr_offset'

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josephlr approved these changes Mar 28, 2022

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josephlr mentioned this pull request Mar 28, 2022

gdt: Improve panic message when SystemSegment is pushed rust-osdev/x86_64#361

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phil-opp merged commit 2c52b5c into rust-osdev:master Mar 28, 2022

phil-opp mentioned this pull request Mar 28, 2022

Remove nightly/stable features when Rust 1.61 is released #23

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phil-opp added a commit that referenced this pull request Mar 28, 2022

Update changelog for #22

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tsatke deleted the patch-1 branch March 28, 2022 10:49

haowqs mentioned this pull request Mar 29, 2022

Fixed uart_16550 version to 0.2.14 confidential-containers/td-shim#192

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haowqs mentioned this pull request Mar 30, 2022

fixed uart_16550 version to 0.2.14 confidential-containers/td-shim#193

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remove unknown nightly feature 'const_ptr_offset' #22

remove unknown nightly feature 'const_ptr_offset' #22

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remove unknown nightly feature 'const_ptr_offset' #22

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