pakrym-oai ddbd1889ca Run write_stdin in parallel across unified-exec sessions (#1992) ...

## Why

`write_stdin` inherited serial tool dispatch, so long polls for
independent unified-exec sessions blocked each other even when the
caller used parallel tool calls or code-mode `Promise.all`.

The useful boundary is the terminal process: independent sessions should
overlap, while operations sharing one process must not overlap because
they mutate stdin, drain one output buffer, and observe the same
lifecycle.

## What changed

- opt `write_stdin` into parallel tool dispatch
- guard each unified-exec process with a process-local interaction mutex
while allowing different process IDs to overlap
- treat a held interaction mutex as a pruning reservation so parallel
`exec_command` calls cannot evict an actively polled process
- revalidate process identity after waiting for that mutex so a stale
waiter cannot redirect input to a replacement process
- add direct non-code and code-mode integration coverage using a
symmetric rendezvous: both sessions can finish only if their
`write_stdin` calls overlap

This does not add a source-order contract for calls targeting the same
session. Their interactions are mutually exclusive, but callers must not
depend on which concurrent call acquires the process mutex first.

## Testing

- `just test -p codex-core write_stdin` (13 passed)
- `just fix -p codex-core`

2026-07-20 18:04:56 -07:00

..

common

Select the elevated Windows sandbox for network proxies (#33445)

2026-07-15 23:19:00 +00:00

remote_env_windows

Scope runtime workspace roots to execution environments (#32952)

2026-07-14 04:41:08 +00:00

suite

Run write_stdin in parallel across unified-exec sessions (#1992)

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all.rs

[codex] Use expect in integration tests (#28441)

2026-06-15 21:53:47 -07:00

responses_headers.rs

Always send reasoning parameters in Responses requests (#32206)

2026-07-10 16:11:58 +00:00