## Summary
Persist Stop-hook continuation prompts as `user` messages instead of
hidden `developer` messages + some requested integration tests
This is a followup to @pakrym 's comment in
https://github.com/openai/codex/pull/14532 to make sure stop-block
continuation prompts match training for turn loops
- Stop continuation now writes `<hook_prompt hook_run_id="...">stop
hook's user prompt<hook_prompt>`
- Introduces quick-xml dependency, though we already indirectly depended
on it anyway via syntect
- This PR only has about 500 lines of actual logic changes, the rest is
tests/schema
## Testing
Example run (with a sessionstart hook and 3 stop hooks) - this shows
context added by session start, then two stop hooks sending their own
additional prompts in a new turn. The model responds with a single
message addressing both. Then when that turn ends, the hooks detect that
they just ran using `stop_hook_active` and decide not to infinite loop
test files for this (unzip, move codex -> .codex):
[codex.zip](https://github.com/user-attachments/files/26075806/codex.zip)
```
› cats
• Running SessionStart hook: lighting the observatory
SessionStart hook (completed)
warning: Hi, I'm a session start hook for wizard-tower (startup).
hook context: A wimboltine stonpet is an exotic cuisine from hyperspace
• Cats are tiny zen wizards, my friend: equal parts nap, mystery, and chaos. If you want, we can talk
cat facts, cat breeds, cat names, or build something cat-themed in this repo.
• Running Stop hook: checking the tower wards
• Running Stop hook: sacking the guards
• Running Stop hook: hiring the guards
Stop hook (completed)
warning: Wizard Tower Stop hook reviewed the completed reply (177 chars).
Stop hook (blocked)
warning: Wizard Tower Stop hook continuing conversation
feedback: cook the stonpet
Stop hook (blocked)
warning: Wizard Tower Stop hook continuing conversation
feedback: eat the cooked stonpet
• Stonpet’s cooked, aloha style: flash-seared over a blue quasiflame, glazed with nebula salt, and
rested until the hyperspace juices settle.
Now we eat with gratitude, my friend. One mindful bite in, and the flavor is pure cosmic surf:
smoky, bright, and totally out of this dimension.
• Running Stop hook: checking the tower wards
• Running Stop hook: sacking the guards
• Running Stop hook: hiring the guards
Stop hook (completed)
warning: Wizard Tower Stop hook reviewed the completed reply (285 chars).
Stop hook (completed)
warning: Wizard Tower Stop hook saw a second pass and stayed calm to avoid a loop.
Stop hook (completed)
warning: Wizard Tower Stop hook saw a second pass and stayed calm to avoid a loop.
```
## Why
PR #13783 moved the `codex.rs` unit tests into `codex_tests.rs`. This
applies the same extraction pattern across the rest of `codex-rs/core`
so the production modules stay focused on runtime code instead of large
inline test blocks.
Keeping the tests in sibling files also makes follow-up edits easier to
review because product changes no longer have to share a file with
hundreds or thousands of lines of test scaffolding.
## What changed
- replaced each inline `mod tests { ... }` in `codex-rs/core/src/**`
with a path-based module declaration
- moved each extracted unit test module into a sibling `*_tests.rs`
file, using `mod_tests.rs` for `mod.rs` modules
- preserved the existing `cfg(...)` guards and module-local structure so
the refactor remains structural rather than behavioral
## Testing
- `cargo test -p codex-core --lib` (`1653 passed; 0 failed; 5 ignored`)
- `just fix -p codex-core`
- `cargo fmt --check`
- `cargo shear`
Andrei Eternal