# Libs Meeting 2025-02-05

###### tags: `Libs Meetings` `Minutes`

**Meeting Link**: https://meet.jit.si/rust-libs-meeting-ujepnbwg2lzqgt6wvrndwimi
**Attendees**: Amanieu, Josh Stone, The 8472, Mara

## Agenda

- Triage
- Anything else?

## Triage

### FCPs

4 rust-lang/rust T-libs FCPs

- merge rust.tf/115746 *Print thread ID in panic message* - (2 checkboxes left)
- merge rust.tf/135080 *core: Make \`Debug\` impl of raw pointers print metadata if present* - (4 checkboxes left)
- merge rust.tf/132484 *unix: Relax escaping in \`Debug\` impl on \`Command\`* - (3 checkboxes left)
- merge rust.tf/133485 *\[discussion\]\[donotmerge\]: Copy Python implementation for \`float::div\_euclid\`* - (3 checkboxes left)

[the8472 (3)](https://rfcbot.rs/fcp/the8472), [m-ou-se (3)](https://rfcbot.rs/fcp/m-ou-se), [cuviper (1)](https://rfcbot.rs/fcp/cuviper), [Amanieu (2)](https://rfcbot.rs/fcp/Amanieu), [joshtriplett (3)](https://rfcbot.rs/fcp/joshtriplett)

### (Nominated) rust.tf/122408 *Use futex\-based synchronization on Apple platforms*

Waiting on review. Unnominated.

### (Nominated) rust.tf/134085 *Run TLS destructors at process exit on all platforms*

Will run TLS destructors on a call to exit().

Last comment says that already happens on linux today..

Previous: https://github.com/rust-lang/rust/pull/133819#issuecomment-2518160203

No clear motivation. Just for the sake of consistency?

The 8472: two steps. next step would be to guarantee this on all platforms in the future.

The 8472: first atexit() in std.

The 8472: takes up global state

Mara: Slightly against this, because of that.

The 8472: If we don't do the second step, why do it at all.

Conclusion: ask for motivation.

Mara replied.

### (Nominated) rust.tf/135634 *stop specializing on \`Copy\`*

Mara: Surprised that it'd be too much of a breaking change to not allow impl'ing Copy depending on the lifetime. Is anyone really doing this?

Mara: Asked for clarification in the types zulip thread.

The 8472: We can run some benchmarks to check the impact. Not sure if the compiler itself is a good benchmark.

### (Nominated) rust.tf/136148 *Optionally add type names to \`TypeId\`s.*

Mara: Seems fine.

The 8472: it's unstable anyway, we wouldn't be promising anything.

JoshS: adds extra write!() even when disabled. Will leave a comment.

### (Nominated) rust.tf/136578 *Add contracts for all functions in \`Alignment\`*

Nora (in a comment): this should only be discussed after the contracts people mentioned above have replied

### (Waiting on team) rust.tf/134536 *Lint on fn pointers comparisons in external macros*

### (Regressions) rust.tf/119560 *\`cargo test\` performance regression on Windows on version 1.75.0*

### (Regressions) rust.tf/53340 *Performance regression in tight loop since rust 1.25*

### (Regressions) rust.tf/112180 *assertion failed: key as usize != KEY\_SENTVAL in DragonFly BSD*

### (Regressions) rust.tf/124216 `P-medium` *Performance regression: rustc failed to optimize \`\_mm256\_avg\_epu8\` after 1.75.0*

### (Regressions) rust.tf/134713 `P-high` *\`std::ptr::swap\_nonoverlapping\` is not always untyped*

### (Regressions) rust.tf/130320 `P-medium` *stdlib code size increase in nightly\-2024\-09\-01 for aarch64\-linux\-android*

## Actions

- [ ] Reply to all issues/PRs discussed in this meeting, or add them to the [open action items](https://hackmd.io/Uehlc0qUQfWfvY1swYWRgQ).

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