mirror of
https://github.com/openai/codex.git
synced 2026-05-03 10:56:37 +00:00
f3989f6092
# Unified Exec Shell Selection on Windows ## Problem reference issue #7466 The `unified_exec` handler currently deserializes model-provided tool calls into the `ExecCommandArgs` struct: ```rust #[derive(Debug, Deserialize)] struct ExecCommandArgs { cmd: String, #[serde(default)] workdir: Option<String>, #[serde(default = "default_shell")] shell: String, #[serde(default = "default_login")] login: bool, #[serde(default = "default_exec_yield_time_ms")] yield_time_ms: u64, #[serde(default)] max_output_tokens: Option<usize>, #[serde(default)] with_escalated_permissions: Option<bool>, #[serde(default)] justification: Option<String>, } ``` The `shell` field uses a hard-coded default: ```rust fn default_shell() -> String { "/bin/bash".to_string() } ``` When the model returns a tool call JSON that only contains `cmd` (which is the common case), Serde fills in `shell` with this default value. Later, `get_command` uses that value as if it were a model-provided shell path: ```rust fn get_command(args: &ExecCommandArgs) -> Vec<String> { let shell = get_shell_by_model_provided_path(&PathBuf::from(args.shell.clone())); shell.derive_exec_args(&args.cmd, args.login) } ``` On Unix, this usually resolves to `/bin/bash` and works as expected. However, on Windows this behavior is problematic: - The hard-coded `"/bin/bash"` is not a valid Windows path. - `get_shell_by_model_provided_path` treats this as a model-specified shell, and tries to resolve it (e.g. via `which::which("bash")`), which may or may not exist and may not behave as intended. - In practice, this leads to commands being executed under a non-default or non-existent shell on Windows (for example, WSL bash), instead of the expected Windows PowerShell or `cmd.exe`. The core of the issue is that **"model did not specify `shell`" is currently interpreted as "the model explicitly requested `/bin/bash`"**, which is both Unix-specific and wrong on Windows. ## Proposed Solution Instead of hard-coding `"/bin/bash"` into `ExecCommandArgs`, we should distinguish between: 1. **The model explicitly specifying a shell**, e.g.: ```json { "cmd": "echo hello", "shell": "pwsh" } ``` In this case, we *do* want to respect the model’s choice and use `get_shell_by_model_provided_path`. 2. **The model omitting the `shell` field entirely**, e.g.: ```json { "cmd": "echo hello" } ``` In this case, we should *not* assume `/bin/bash`. Instead, we should use `default_user_shell()` and let the platform decide. To express this distinction, we can: 1. Change `shell` to be optional in `ExecCommandArgs`: ```rust #[derive(Debug, Deserialize)] struct ExecCommandArgs { cmd: String, #[serde(default)] workdir: Option<String>, #[serde(default)] shell: Option<String>, #[serde(default = "default_login")] login: bool, #[serde(default = "default_exec_yield_time_ms")] yield_time_ms: u64, #[serde(default)] max_output_tokens: Option<usize>, #[serde(default)] with_escalated_permissions: Option<bool>, #[serde(default)] justification: Option<String>, } ``` Here, the absence of `shell` in the JSON is represented as `shell: None`, rather than a hard-coded string value.