Summary
- mark `output-last-message` as a global exec flag so it can follow
subcommands like `resume`
- add regression tests in both `cli` and `exec` crates verifying the
flag order works when invoking `resume`
Fixes#12538
## Why
The current escalate path in `codex-rs/exec-server` still had policy
creation coupled to MCP details, which makes it hard to reuse the shell
execution flow outside the MCP server. This change is part of a broader
goal to split MCP-specific behavior from shared escalation execution so
other handlers (for example a future `ShellCommandHandler`) can reuse it
without depending on MCP request context types.
## What changed
- Added a new `EscalationPolicyFactory` abstraction in `mcp.rs`:
- `crate`-relative path: `codex-rs/exec-server/src/posix/mcp.rs`
-
https://github.com/openai/codex/blob/main/codex-rs/exec-server/src/posix/mcp.rs#L87-L107
- Made `run_escalate_server` in `mcp.rs` accept a policy factory instead
of constructing `McpEscalationPolicy` directly.
-
https://github.com/openai/codex/blob/main/codex-rs/exec-server/src/posix/mcp.rs#L178-L201
- Introduced `McpEscalationPolicyFactory` that stores MCP-only state
(`RequestContext`, `preserve_program_paths`) and implements the new
trait.
-
https://github.com/openai/codex/blob/main/codex-rs/exec-server/src/posix/mcp.rs#L100-L117
- Updated `shell()` to pass a `McpEscalationPolicyFactory` instance into
`run_escalate_server`, so the server remains the MCP-specific wiring
layer.
-
https://github.com/openai/codex/blob/main/codex-rs/exec-server/src/posix/mcp.rs#L163-L170
## Verification
- Build and test execution was not re-run in this pass; changes are
limited to `mcp.rs` and preserve the existing escalation flow semantics
by only extracting policy construction behind a factory.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/12555).
* #12556
* __->__ #12555
## Why
The zsh integration tests were still brittle in two ways:
- they relied on `CODEX_TEST_ZSH_PATH` / environment-specific setup, so
they often did not exercise the patched zsh fork that `shell-tool-mcp`
ships
- once the tests consistently used the vendored zsh fork, they exposed
real Linux-specific zsh-fork issues in CI
In particular, the Linux failures were not just test noise:
- the zsh-fork launch path was dropping `ExecRequest.arg0`, so Linux
`codex-linux-sandbox` arg0 dispatch did not run and zsh wrapper-mode
could receive malformed arguments
- the
`turn_start_shell_zsh_fork_subcommand_decline_marks_parent_declined_v2`
test uses the zsh exec bridge (which talks to the parent over a Unix
socket), but Linux restricted sandbox seccomp denies `connect(2)`,
causing timeouts on `ubuntu-24.04` x86/arm
This PR makes the zsh tests consistently run against the intended
vendored zsh fork and fixes/hardens the zsh-fork path so the Linux CI
signal is meaningful.
## What Changed
- Added a single shared test-only DotSlash file for the patched zsh fork
at `codex-rs/exec-server/tests/suite/zsh` (analogous to the existing
`bash` test resource).
- Updated both app-server and exec-server zsh tests to use that shared
DotSlash zsh (no duplicate zsh DotSlash file, no `CODEX_TEST_ZSH_PATH`
dependency).
- Updated the app-server zsh-fork test helper to resolve the shared
DotSlash zsh and avoid silently falling back to host zsh.
- Kept the app-server zsh-fork tests configured via `config.toml`, using
a test wrapper path where needed to force `zsh -df` (and rewrite `-lc`
to `-c`) for the subcommand-decline test.
- Hardened the app-server subcommand-decline zsh-fork test for CI
variability:
- tolerate an extra `/responses` POST with a no-op mock response
- tolerate non-target approval ordering while remaining strict on the
two `/usr/bin/true` approvals and decline behavior
- use `DangerFullAccess` on Linux for this one test because it validates
zsh approval flow, not Linux sandbox socket restrictions
- Fixed zsh-fork process launching on Linux by preserving `req.arg0` in
`ZshExecBridge::execute_shell_request(...)` so `codex-linux-sandbox`
arg0 dispatch continues to work.
- Moved `maybe_run_zsh_exec_wrapper_mode()` under
`arg0_dispatch_or_else(...)` in `app-server` and `cli` so wrapper-mode
handling coexists correctly with arg0-dispatched helper modes.
- Consolidated duplicated `dotslash -- fetch` resolution logic into
shared test support (`core/tests/common/lib.rs`).
- Updated `codex-rs/exec-server/tests/suite/accept_elicitation.rs` to
use DotSlash zsh and hardened the zsh elicitation test for Bazel/zsh
differences by:
- resolving an absolute `git` path
- running `git init --quiet .`
- asserting success / `.git` creation instead of relying on banner text
## Verification
- `cargo test -p codex-app-server turn_start_zsh_fork -- --nocapture`
- `cargo test -p codex-exec-server accept_elicitation -- --nocapture`
- `bazel test //codex-rs/exec-server:exec-server-all-test
--test_output=streamed --test_arg=--nocapture
--test_arg=accept_elicitation_for_prompt_rule_with_zsh`
- CI (`rust-ci`) on the final cleaned commit: `Tests — ubuntu-24.04 -
x86_64-unknown-linux-gnu` and `Tests — ubuntu-24.04-arm -
aarch64-unknown-linux-gnu` passed in [run
22291424358](https://github.com/openai/codex/actions/runs/22291424358)