Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Broaden the consequences of recursive TLS initialization #116172

Merged
merged 1 commit into from
Oct 15, 2023

Conversation

joboet
Copy link
Member

@joboet joboet commented Sep 26, 2023

This PR updates the documentation of LocalKey to clearly disallow the behaviour described in this comment. This allows using OnceCell for the lazy initialization of TLS variables, which panics on reentrant initialization instead of updating the value like TLS variables currently do.

@rustbot label +T-libs-api
r? @m-ou-se

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. labels Sep 26, 2023
@m-ou-se m-ou-se removed the T-libs Relevant to the library team, which will review and decide on the PR/issue. label Sep 26, 2023
@m-ou-se
Copy link
Member

m-ou-se commented Sep 26, 2023

@rfcbot merge

This allows thread locals to be implemented as a OnceCell.

(Right now, the behavior is a bit weird: you can initialize a thread local twice (or more) by recursively using .with. So, a non-mutable thread local can have different values over its lifetime, which seems like a bug to me. See discussion starting here: #110897 (comment))

@rfcbot
Copy link

rfcbot commented Sep 26, 2023

Team member @m-ou-se has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

@rfcbot rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Sep 26, 2023
@m-ou-se m-ou-se added S-waiting-on-fcp Status: PR is in FCP and is awaiting for FCP to complete. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 26, 2023
@rfcbot rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Oct 5, 2023
@rfcbot
Copy link

rfcbot commented Oct 5, 2023

🔔 This is now entering its final comment period, as per the review above. 🔔

@rfcbot rfcbot added finished-final-comment-period The final comment period is finished for this PR / Issue. to-announce Announce this issue on triage meeting and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Oct 15, 2023
@rfcbot
Copy link

rfcbot commented Oct 15, 2023

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

Copy link
Member

@dtolnay dtolnay left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thank you!

@dtolnay
Copy link
Member

dtolnay commented Oct 15, 2023

@bors r+ rollup

@bors
Copy link
Contributor

bors commented Oct 15, 2023

📌 Commit 559ec69 has been approved by dtolnay

It is now in the queue for this repository.

@bors bors added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Oct 15, 2023
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 15, 2023
…n, r=dtolnay

Broaden the consequences of recursive TLS initialization

This PR updates the documentation of `LocalKey` to clearly disallow the behaviour described in [this comment](rust-lang#110897 (comment)). This allows using `OnceCell` for the lazy initialization of TLS variables, which panics on reentrant initialization instead of updating the value like TLS variables currently do.

`@rustbot` label +T-libs-api
r? `@m-ou-se`
bors added a commit to rust-lang-ci/rust that referenced this pull request Oct 15, 2023
…iaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#115955 (Stabilize `{IpAddr, Ipv6Addr}::to_canonical`)
 - rust-lang#116033 (report `unused_import` for empty reexports even it is pub)
 - rust-lang#116172 (Broaden the consequences of recursive TLS initialization)
 - rust-lang#116341 (Implement sys::args for UEFI)
 - rust-lang#116522 (use `PatKind::Error` when an ADT const value has violation)
 - rust-lang#116732 (Make x capable of resolving symlinks)
 - rust-lang#116755 (Remove me from libcore review rotation)
 - rust-lang#116760 (Remove trivial cast in `guaranteed_eq`)

r? `@ghost`
`@rustbot` modify labels: rollup
bors added a commit to rust-lang-ci/rust that referenced this pull request Oct 15, 2023
…iaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#116172 (Broaden the consequences of recursive TLS initialization)
 - rust-lang#116341 (Implement sys::args for UEFI)
 - rust-lang#116522 (use `PatKind::Error` when an ADT const value has violation)
 - rust-lang#116732 (Make x capable of resolving symlinks)
 - rust-lang#116755 (Remove me from libcore review rotation)
 - rust-lang#116760 (Remove trivial cast in `guaranteed_eq`)
 - rust-lang#116771 (Ignore let-chains formatting)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit e063d8a into rust-lang:master Oct 15, 2023
11 checks passed
@rustbot rustbot added this to the 1.75.0 milestone Oct 15, 2023
rust-timer added a commit to rust-lang-ci/rust that referenced this pull request Oct 15, 2023
Rollup merge of rust-lang#116172 - joboet:recursive_tls_initialization, r=dtolnay

Broaden the consequences of recursive TLS initialization

This PR updates the documentation of `LocalKey` to clearly disallow the behaviour described in [this comment](rust-lang#110897 (comment)). This allows using `OnceCell` for the lazy initialization of TLS variables, which panics on reentrant initialization instead of updating the value like TLS variables currently do.

``@rustbot`` label +T-libs-api
r? ``@m-ou-se``
bors-ferrocene bot added a commit to ferrocene/ferrocene that referenced this pull request Oct 17, 2023
54: Pull upstream master 2023 10 17 r=pietroalbini a=Veykril

* rust-lang/rust#116196
* rust-lang/rust#116824
* rust-lang/rust#116822
* rust-lang/rust#116477
* rust-lang/rust#116826
* rust-lang/rust#116820
  * rust-lang/rust#116811
  * rust-lang/rust#116808
  * rust-lang/rust#116805
  * rust-lang/rust#116800
  * rust-lang/rust#116798
  * rust-lang/rust#116754
* rust-lang/rust#114370
* rust-lang/rust#116804
  * rust-lang/rust#116802
  * rust-lang/rust#116790
  * rust-lang/rust#116786
  * rust-lang/rust#116709
  * rust-lang/rust#116430
  * rust-lang/rust#116257
  * rust-lang/rust#114157
* rust-lang/rust#116731
* rust-lang/rust#116550
* rust-lang/rust#114330
* rust-lang/rust#116724
* rust-lang/rust#116782
  * rust-lang/rust#116776
  * rust-lang/rust#115955
  * rust-lang/rust#115196
* rust-lang/rust#116775
* rust-lang/rust#114589
* rust-lang/rust#113747
* rust-lang/rust#116772
  * rust-lang/rust#116771
  * rust-lang/rust#116760
  * rust-lang/rust#116755
  * rust-lang/rust#116732
  * rust-lang/rust#116522
  * rust-lang/rust#116341
  * rust-lang/rust#116172
* rust-lang/rust#110604
* rust-lang/rust#110729
* rust-lang/rust#116527
* rust-lang/rust#116688
* rust-lang/rust#116757
  * rust-lang/rust#116753
  * rust-lang/rust#116748
  * rust-lang/rust#116741
  * rust-lang/rust#116594
* rust-lang/rust#116691
* rust-lang/rust#116643
* rust-lang/rust#116683
* rust-lang/rust#116635
* rust-lang/rust#115515
* rust-lang/rust#116742
  * rust-lang/rust#116661
  * rust-lang/rust#116576
  * rust-lang/rust#116540
* rust-lang/rust#116352
* rust-lang/rust#116737
  * rust-lang/rust#116730
  * rust-lang/rust#116723
  * rust-lang/rust#116715
  * rust-lang/rust#116603
  * rust-lang/rust#116591
  * rust-lang/rust#115439
* rust-lang/rust#116264
* rust-lang/rust#116727
  * rust-lang/rust#116704
  * rust-lang/rust#116696
  * rust-lang/rust#116695
  * rust-lang/rust#116644
  * rust-lang/rust#116630
* rust-lang/rust#116728
  * rust-lang/rust#116689
  * rust-lang/rust#116679
  * rust-lang/rust#116618
  * rust-lang/rust#116577
  * rust-lang/rust#115653
* rust-lang/rust#116702
* rust-lang/rust#116015
* rust-lang/rust#115822
* rust-lang/rust#116407
* rust-lang/rust#115719
* rust-lang/rust#115524
* rust-lang/rust#116705
* rust-lang/rust#116645
* rust-lang/rust#116233
* rust-lang/rust#115108
* rust-lang/rust#116670
* rust-lang/rust#116676
* rust-lang/rust#116666



Co-authored-by: Benoît du Garreau <bdgdlm@outlook.com>
Co-authored-by: Colin Finck <colin@reactos.org>
Co-authored-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Co-authored-by: Joshua Liebow-Feeser <joshlf@users.noreply.github.com>
Co-authored-by: León Orell Valerian Liehr <me@fmease.dev>
Co-authored-by: Trevor Gross <tmgross@umich.edu>
Co-authored-by: Evan Merlock <evan@merlock.dev>
Co-authored-by: joboet <jonasboettiger@icloud.com>
Co-authored-by: Ralf Jung <post@ralfj.de>
Co-authored-by: DaniPopes <57450786+DaniPopes@users.noreply.github.com>
Co-authored-by: Mark Rousskov <mark.simulacrum@gmail.com>
Co-authored-by: onur-ozkan <work@onurozkan.dev>
Co-authored-by: Nicholas Nethercote <n.nethercote@gmail.com>
Co-authored-by: The 8472 <git@infinite-source.de>
Co-authored-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Co-authored-by: reez12g <reez12g@gmail.com>
Co-authored-by: Jakub Beránek <berykubik@gmail.com>
@apiraino apiraino removed the to-announce Announce this issue on triage meeting label Oct 19, 2023
@joboet joboet deleted the recursive_tls_initialization branch December 29, 2023 10:42
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Mar 3, 2024
Pkgsrc changes:
 * Adjust patches and cargo checksums to new versions.
 * For an external LLVM, set dependency of llvm >= 16, in accordance
   with the upstream changes.
 * Mark that on NetBSD we now need >= 9.0, so 8.x is no longer supported.
 * On NetBSD/sparc64 10.x, we now need GCC 12 to build the embedded
   LLVM, which is version 17; apparently GCC 10.4 or 10.5 mis-compiles it,
   resulting in an illegal instruction fault during the build.
   Ref. rust-lang/rust#117231

Upstream changes:

Version 1.75.0 (2023-12-28)
==========================

- [Stabilize `async fn` and return-position `impl Trait` in traits.]
  (rust-lang/rust#115822)
- [Allow function pointer signatures containing `&mut T` in `const` contexts.]
  (rust-lang/rust#116015)
- [Match `usize`/`isize` exhaustively with half-open ranges.]
  (rust-lang/rust#116692)
- [Guarantee that `char` has the same size and alignment as `u32`.]
  (rust-lang/rust#116894)
- [Document that the null pointer has the 0 address.]
  (rust-lang/rust#116988)
- [Allow partially moved values in `match`.]
  (rust-lang/rust#103208)
- [Add notes about non-compliant FP behavior on 32bit x86 targets.]
  (rust-lang/rust#113053)
- [Stabilize ratified RISC-V target features.]
  (rust-lang/rust#116485)

Compiler
--------

- [Rework negative coherence to properly consider impls that only
  partly overlap.] (rust-lang/rust#112875)
- [Bump `COINDUCTIVE_OVERLAP_IN_COHERENCE` to deny, and warn in dependencies.]
  (rust-lang/rust#116493)
- [Consider alias bounds when computing liveness in NLL.]
  (rust-lang/rust#116733)
- [Add the V (vector) extension to the `riscv64-linux-android` target spec.]
  (rust-lang/rust#116618)
- [Automatically enable cross-crate inlining for small functions]
  (rust-lang/rust#116505)
- Add several new tier 3 targets:
    - [`csky-unknown-linux-gnuabiv2hf`]
      (rust-lang/rust#117049)
    - [`i586-unknown-netbsd`]
      (rust-lang/rust#117170)
    - [`mipsel-unknown-netbsd`]
      (rust-lang/rust#117356)

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------

- [Override `Waker::clone_from` to avoid cloning `Waker`s unnecessarily.]
  (rust-lang/rust#96979)
- [Implement `BufRead` for `VecDeque<u8>`.]
  (rust-lang/rust#110604)
- [Implement `FusedIterator` for `DecodeUtf16` when the inner iterator does.]
  (rust-lang/rust#110729)
- [Implement `Not, Bit{And,Or}{,Assign}` for IP addresses.]
  (rust-lang/rust#113747)
- [Implement `Default` for `ExitCode`.]
  (rust-lang/rust#114589)
- [Guarantee representation of None in NPO]
  (rust-lang/rust#115333)
- [Document when atomic loads are guaranteed read-only.]
  (rust-lang/rust#115577)
- [Broaden the consequences of recursive TLS initialization.]
  (rust-lang/rust#116172)
- [Windows: Support sub-millisecond sleep.]
  (rust-lang/rust#116461)
- [Fix generic bound of `str::SplitInclusive`'s `DoubleEndedIterator` impl]
  (rust-lang/rust#100806)
- [Fix exit status / wait status on non-Unix `cfg(unix)` platforms.]
  (rust-lang/rust#115108)

Stabilized APIs
---------------

- [`Atomic*::from_ptr`]
  (https://doc.rust-lang.org/stable/core/sync/atomic/struct.AtomicUsize.html#method.from_ptr)
- [`FileTimes`]
  (https://doc.rust-lang.org/stable/std/fs/struct.FileTimes.html)
- [`FileTimesExt`]
  (https://doc.rust-lang.org/stable/std/os/windows/fs/trait.FileTimesExt.html)
- [`File::set_modified`]
  (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.set_modified)
- [`File::set_times`]
  (https://doc.rust-lang.org/stable/std/fs/struct.File.html#method.set_times)
- [`IpAddr::to_canonical`]
  (https://doc.rust-lang.org/stable/core/net/enum.IpAddr.html#method.to_canonical)
- [`Ipv6Addr::to_canonical`]
  (https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.to_canonical)
- [`Option::as_slice`]
  (https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_slice)
- [`Option::as_mut_slice`]
  (https://doc.rust-lang.org/stable/core/option/enum.Option.html#method.as_mut_slice)
- [`pointer::byte_add`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_add)
- [`pointer::byte_offset`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_offset)
- [`pointer::byte_offset_from`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_offset_from)
- [`pointer::byte_sub`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.byte_sub)
- [`pointer::wrapping_byte_add`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_add)
- [`pointer::wrapping_byte_offset`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_offset)
- [`pointer::wrapping_byte_sub`]
  (https://doc.rust-lang.org/stable/core/primitive.pointer.html#method.wrapping_byte_sub)

These APIs are now stable in const contexts:

- [`Ipv6Addr::to_ipv4_mapped`]
  (https://doc.rust-lang.org/stable/core/net/struct.Ipv6Addr.html#method.to_ipv4_mapped)
- [`MaybeUninit::assume_init_read`]
  (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.assume_init_read)
- [`MaybeUninit::zeroed`]
  (https://doc.rust-lang.org/stable/core/mem/union.MaybeUninit.html#method.zeroed)
- [`mem::discriminant`]
  (https://doc.rust-lang.org/stable/core/mem/fn.discriminant.html)
- [`mem::zeroed`]
  (https://doc.rust-lang.org/stable/core/mem/fn.zeroed.html)

Cargo
-----

- [Add new packages to `[workspace.members]` automatically.]
  (rust-lang/cargo#12779)
- [Allow version-less `Cargo.toml` manifests.]
  (rust-lang/cargo#12786)
- [Make browser links out of HTML file paths.]
  (rust-lang/cargo#12889)

Rustdoc
-------

- [Accept less invalid Rust in rustdoc.]
  (rust-lang/rust#117450)
- [Document lack of object safety on affected traits.]
  (rust-lang/rust#113241)
- [Hide `#[repr(transparent)]` if it isn't part of the public ABI.]
  (rust-lang/rust#115439)
- [Show enum discriminant if it is a C-like variant.]
  (rust-lang/rust#116142)

Compatibility Notes
-------------------

- [FreeBSD targets now require at least version 12.]
  (rust-lang/rust#114521)
- [Formally demote tier 2 MIPS targets to tier 3.]
  (rust-lang/rust#115238)
- [Make misalignment a hard error in `const` contexts.]
  (rust-lang/rust#115524)
- [Fix detecting references to packed unsized fields.]
  (rust-lang/rust#115583)
- [Remove support for compiler plugins.]
  (rust-lang/rust#116412)
@dtolnay dtolnay self-assigned this Mar 24, 2024
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. finished-final-comment-period The final comment period is finished for this PR / Issue. S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. S-waiting-on-fcp Status: PR is in FCP and is awaiting for FCP to complete. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.
Projects
None yet
Development

Successfully merging this pull request may close these issues.

7 participants