Tracking Issue for PanicHookInfo::payload_as_str()

[m-ou-se]

Feature gate: #![feature(panic_payload_as_str)]

This is a tracking issue for PanicHookInfo::payload_as_str()

Public API

// std::panic

impl PanicHookInfo {
    pub fn payload_as_str(&self) -> Option<&str>;
}

Documentation: https://doc.rust-lang.org/nightly/std/panic/struct.PanicHookInfo.html#method.payload_as_str

Steps / History

• Implementation: part of Split core's PanicInfo and std's PanicInfo #115974
• Final comment period (FCP)
• Stabilization PR: Stabilize panic_payload_as_str feature #144861

Unresolved Questions

• None yet.

[m-ou-se]

PanicHookInfo (as a separate type from PanicInfo) has been stablized. Time to stabilize PanicHookInfo::payload_as_str(). :)

This replaces the 'try to cast to str otherwise try to cast to String' pattern that basically every user of PanicHookInfo is doing today.

@rfcbot merge

[rfcbot]

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

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @m-ou-se

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]

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

[madsmtm]

The documentation on payload_as_str is reproduced here:

Returns the payload associated with the panic, if it is a string.

This returns the payload if it is of type &'static str or String.

A invocation of the panic!() macro in Rust 2021 or later will always result in a panic payload where payload_as_str returns Some.

Only an invocation of panic_any (or, in Rust 2018 and earlier, panic!(x) where x is something other than a string) can result in a panic payload where payload_as_str returns None.

I'm unsure, would you say that it is written in such a way that we could allow changing it to also internally also cast e.g. Box<str> or Cow<'static, str>, or perhaps even dyn AsRef<str>? If not, then I think perhaps that should be changed before stabilization?