DioxusLabs / DioxusLabs/dioxus
Errors when running Bevy hotpatching example: Missing rustc capture and Missing rustc args for replay
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- 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
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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