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Tracking Issue for panic_any #78500

Closed
3 tasks done
m-ou-se opened this issue Oct 28, 2020 · 8 comments
Closed
3 tasks done

Tracking Issue for panic_any #78500

m-ou-se opened this issue Oct 28, 2020 · 8 comments
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A-error-handling Area: Error handling A-runtime Area: std's runtime and "pre-main" init for handling backtraces, unwinds, stack overflows C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. 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. Libs-Tracked Libs issues that are tracked on the team's project board. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.

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@m-ou-se
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m-ou-se commented Oct 28, 2020

Feature gate: #![feature(panic_any)]

This is a tracking issue for std::panic::panic_any, a function to allow panicking with any value.

Context

Right now, it is possible to panic (that is, std::panic!) on any value: panic!(123). This will be disallowed in Rust 2021, when panic!(..) will always take a format string just like println!(..). At that point, this function will be the only way to panic without a (format) string. (See #80162 and rust-lang/rfcs#3007.)

Public API

mod std::panic {

    /// Panic the current thread with the given message as the panic payload.
    ///
    /// The message can be of any (`Any + Send`) type, not just strings.
    ///
    /// The message is wrapped in a `Box<'static + Any + Send>`, which can be
    /// accessed later using [`PanicInfo::payload`].
    ///
    /// See the [`panic!`] macro for more information about panicking.
    pub fn panic_any<M: Any + Send>(msg: M) -> !;

}

Steps / History

Unresolved Questions

  • None yet.
@m-ou-se m-ou-se added T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. labels Oct 28, 2020
@camelid camelid added the A-runtime Area: std's runtime and "pre-main" init for handling backtraces, unwinds, stack overflows label Oct 28, 2020
@KodrAus KodrAus added the Libs-Tracked Libs issues that are tracked on the team's project board. label Nov 6, 2020
@KodrAus KodrAus added the A-error-handling Area: Error handling label Nov 28, 2020
@m-ou-se
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m-ou-se commented Jan 9, 2021

@rfcbot merge

Once this is stable, we can add a lint about using this function instead of panic!(x) for non-strings, as part of RFC 3007 (see #80162).

@rfcbot
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rfcbot commented Jan 9, 2021

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 Jan 9, 2021
@sfackler
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sfackler commented Jan 9, 2021

It seems like the function signature is missing a 'static bound?

@m-ou-se
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m-ou-se commented Jan 9, 2021

It seems like the function signature is missing a 'static bound?

Any: 'static already requires that. I can add it in the stabilization PR to make it explicit.

@sfackler
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sfackler commented Jan 9, 2021

Oh right, I think I asked this same question when this function was added! Yeah, might be best to add the duplicate bound in.

@rfcbot rfcbot added the final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. label Jan 9, 2021
@rfcbot
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rfcbot commented Jan 9, 2021

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

@rfcbot rfcbot removed the proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. label Jan 9, 2021
@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 Jan 19, 2021
@rfcbot
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rfcbot commented Jan 19, 2021

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.

The RFC will be merged soon.

@apiraino apiraino removed the to-announce Announce this issue on triage meeting label Jan 21, 2021
@KodrAus
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KodrAus commented Jan 29, 2021

Now that this is stable I'll go ahead and close this tracking issue. Please feel free to re-open if we'd like to keep it around until 1.51.0 actually ships!

cratelyn pushed a commit to cratelyn/rust that referenced this issue Mar 3, 2021
 ### Integration Tests

    This commit introduces some new fixtures to the `run-make-fulldeps`
    test suite.

        * c-unwind-abi-catch-panic: Exercise unwinding a panic. This
          catches a panic across an FFI boundary and downcasts it into
          an integer.

        * c-unwind-abi-catch-lib-panic: This is similar to the previous
         `*catch-panic` test, however in this case the Rust code that
         panics resides in a separate crate.

 ### Add `rust_eh_personality` to `#[no_std]` alloc tests

    This commit addresses some test failures that now occur in the
    following two tests:

        * no_std-alloc-error-handler-custom.rs
        * no_std-alloc-error-handler-default.rs

    Each test now defines a `rust_eh_personality` extern function, in
    the same manner as shown in the "Writing an executable without
    stdlib" section of the `lang_items` documentation here:
    https://doc.rust-lang.org/unstable-book/language-features/lang-items.html#writing-an-executable-without-stdlib

    Without this change, these tests would fail to compile due to a
    linking error explaining that there was an "undefined reference
    to `rust_eh_personality'."

 ### Updated hash

    * update 32-bit hash in `impl1` test

 ### Panics

    This commit uses `panic!` macro invocations that return a string,
    rather than using an integer as a panic payload.

    Doing so avoids the following warnings that were observed during
    rollup for the `*-msvc-1` targets:

    ```
    warning: panic message is not a string literal
      --> panic.rs:10:16
       |
    10 |         panic!(x); // That is too big!
       |                ^
       |
       = note: `#[warn(non_fmt_panic)]` on by default
       = note: this is no longer accepted in Rust 2021
    help: add a "{}" format string to Display the message
       |
    10 |         panic!("{}", x); // That is too big!
       |                ^^^^^
    help: or use std::panic::panic_any instead
       |
    10 |         std::panic::panic_any(x); // That is too big!
       |         ^^^^^^^^^^^^^^^^^^^^^

    warning: 1 warning emitted
    ```

    See: https://github.com/rust-lang-ci/rust/runs/1992118428

    As these errors imply, panicking without a format string will be
    disallowed in Rust 2021, per rust-lang#78500.
cratelyn pushed a commit to cratelyn/rust that referenced this issue Mar 9, 2021
 ### Integration Tests

    This commit introduces some new fixtures to the `run-make-fulldeps`
    test suite.

        * c-unwind-abi-catch-panic: Exercise unwinding a panic. This
          catches a panic across an FFI boundary and downcasts it into
          an integer.

        * c-unwind-abi-catch-lib-panic: This is similar to the previous
         `*catch-panic` test, however in this case the Rust code that
         panics resides in a separate crate.

 ### Add `rust_eh_personality` to `#[no_std]` alloc tests

    This commit addresses some test failures that now occur in the
    following two tests:

        * no_std-alloc-error-handler-custom.rs
        * no_std-alloc-error-handler-default.rs

    Each test now defines a `rust_eh_personality` extern function, in
    the same manner as shown in the "Writing an executable without
    stdlib" section of the `lang_items` documentation here:
    https://doc.rust-lang.org/unstable-book/language-features/lang-items.html#writing-an-executable-without-stdlib

    Without this change, these tests would fail to compile due to a
    linking error explaining that there was an "undefined reference
    to `rust_eh_personality'."

 ### Updated hash

    * update 32-bit hash in `impl1` test

 ### Panics

    This commit uses `panic!` macro invocations that return a string,
    rather than using an integer as a panic payload.

    Doing so avoids the following warnings that were observed during
    rollup for the `*-msvc-1` targets:

    ```
    warning: panic message is not a string literal
      --> panic.rs:10:16
       |
    10 |         panic!(x); // That is too big!
       |                ^
       |
       = note: `#[warn(non_fmt_panic)]` on by default
       = note: this is no longer accepted in Rust 2021
    help: add a "{}" format string to Display the message
       |
    10 |         panic!("{}", x); // That is too big!
       |                ^^^^^
    help: or use std::panic::panic_any instead
       |
    10 |         std::panic::panic_any(x); // That is too big!
       |         ^^^^^^^^^^^^^^^^^^^^^

    warning: 1 warning emitted
    ```

    See: https://github.com/rust-lang-ci/rust/runs/1992118428

    As these errors imply, panicking without a format string will be
    disallowed in Rust 2021, per rust-lang#78500.
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Labels
A-error-handling Area: Error handling A-runtime Area: std's runtime and "pre-main" init for handling backtraces, unwinds, stack overflows C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. 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. Libs-Tracked Libs issues that are tracked on the team's project board. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.
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