## What changed
- The PTY Python REPL test now starts Python with a startup marker
already embedded in argv.
- The test waits for that marker in PTY output before making assertions.
## Why this fixes the flake
- The old version tried to probe the live REPL almost immediately after
spawn.
- That races PTY initialization, Python startup, and prompt buffering,
all of which vary across platforms and CI load.
- By having the child process emit a known marker as part of its own
startup path, the test gets a deterministic synchronization point that
comes from the process under test rather than from guessed timing.
## Scope
- Test-only change.
Addresses #13945
The vendored WezTerm ConPTY backend in
`codex-rs/utils/pty/src/win/mod.rs` treated `TerminateProcess` return
values backwards: nonzero success was handled as failure, and `0`
failure was handled as success.
This is likely causing a number of bugs reported against Codex running
on Windows native where processes are not cleaned up.
Enhance pty utils:
* Support closing stdin
* Separate stderr and stdout streams to allow consumers differentiate them
* Provide compatibility helper to merge both streams back into combined one
* Support specifying terminal size for pty, including on-demand resizes while process is already running
* Support terminating the process while still consuming its outputs
Hardens PTY Python REPL test and make MCP test startup deterministic
**Summary**
- `utils/pty/src/tests.rs`
- Added a REPL readiness handshake (`wait_for_python_repl_ready`) that
repeatedly sends a marker and waits for it in PTY output before sending
test commands.
- Updated `pty_python_repl_emits_output_and_exits` to:
- wait for readiness first,
- preserve startup output,
- append output collected through process exit.
- Reduces Windows/ConPTY flakiness from early stdin writes racing REPL
startup.
- `mcp-server/tests/suite/codex_tool.rs`
- Avoid remote model refresh during MCP test startup, reducing
timeout-prone nondeterminism.
This PR changes stdio MCP child processes to run in their own process
group
* Add guarded teardown in codex-rmcp-client: send SIGTERM to the group
first, then SIGKILL after a short grace period.
* Add terminate_process_group helper in process_group.rs.
* Add Unix regression test in process_group_cleanup.rs to verify wrapper
+ grandchild are reaped on client drop.
Addresses reported MCP process/thread storm: #10581
Unified exec isn't working on Linux because we don't provide the correct
arg0.
The library we use for pty management doesn't allow setting arg0
separately from executable. Use the same aliasing strategy we use for
`apply_patch` for `codex-linux-sandbox`.
Use `#[ctor]` hack to dispatch codex-linux-sandbox calls.
Addresses https://github.com/openai/codex/issues/6450
Ahmed IbrahimandGitHub
Eric TrautandGitHub
Ruslan NigmatullinandGitHub
jif-oaiandGitHub
