DioxusLabs / DioxusLabs/dioxus

Errors when running Bevy hotpatching example: Missing rustc capture and Missing rustc args for replay

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#5,813 2 comments 1 reaction 0 assignees View on GitHub
bug
Dominant language
Rust
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Description

**Problem**

I tried to run Bevy's `hotpatching_systems` example (with `--hot-patch`). The build runs okay, but subsequent hot patching shows the following errors:

On 1.100 (nightly), the program fails to start with `Missing rustc capture`.

On 1.98.1 (stable), the program launches, but making a change and triggering a hot patch errors with `Missing rustc args for replay: auto_register_static`. (In this case, I tried editing the text color and text string in the example project.)

I believe these issues may have a related root cause, so I'm reporting them together.

**Steps To Reproduce**

- Pull the Bevy repo (`git clone https://github.com/bevyengine/bevy`, I used the latest dev branch)
- Run with `dx serve --hot-patch --example hotpatching_systems --features hotpatching`
- The entire build runs without issue
- On nightly 1.100, when dx tries to start the program, it fails with `Missing rustc capture`
- On stable 1.98.1, the program starts, but hot-patches fail with `Missing rustc args for replay: auto_register_static`
- Triggering a full rebuild or re-running `dx serve` errors the same way

**Expected behavior**

The example should start/hot-patch as expected.

**Environment:**

- Dioxus version: dioxus 0.7.10 (57d6794)
- Rust version: rustc 1.98.1 (48a229cea 2026-09-01); rustc 1.100.0-nightly (0ed41eb41 2026-09-04)
- OS info: Windows 11
- App platform: Desktop

**More details & observations**
- `cargo clean` did not help
- In `.captured-args`, the 1.98.1 build _had_ a file matching the tip crate called `hotpatching_systems.bin.json`, but the 1.100 build did not. Could this be why the nightly build failed to start?
- Both builds also had `.captured-args` files for a bunch of `bevy-*` crates, but nothing else (including `auto_register_static`, as per the rustc args replay error).
- I tried `dx serve --hot-patch` on Rust 1.100 on another small project of mine that uses egui. This worked and hot-patched without issue. The tip crate `{crate}.bin.json` was also present in `.captured-args` (but nothing else).
- Could this somehow be related to running an `--example` with hot patching? I also remember that Cargo had some [notable changes in 1.100](https://doc.rust-lang.org/nightly/cargo/CHANGELOG.html#cargo-1100-2026-11-12), could this be somehow related?

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the hotpatching_systems example and the `dx serve --hot-patch --example hotpatching_systems --features hotpatching` command. Inspect how `.captured-args` files are produced and replayed, comparing the stable and nightly cases, including the missing `auto_register_static` entry. Done means the example starts and accepts a hot patch without either reported error.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
build-system, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
48/100

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