Stage 4

README.md: 
codetracer-python-recorder/Cargo.lock: 
codetracer-python-recorder/Cargo.toml: 
codetracer-python-recorder/src/policy.rs: 
codetracer-python-recorder/src/runtime/io_capture/fd_mirror.rs: 
codetracer-python-recorder/src/runtime/io_capture/install.rs: 
codetracer-python-recorder/src/runtime/io_capture/mod.rs: 
codetracer-python-recorder/src/runtime/io_capture/proxies.rs: 
codetracer-python-recorder/src/runtime/io_capture/sink.rs: 
codetracer-python-recorder/src/runtime/mod.rs: 
design-docs/adr/0008-line-aware-io-capture.md: 
design-docs/io-capture-line-proxy-implementation-plan.md: 
design-docs/io-capture-line-proxy-implementation-plan.status.md: 

Signed-off-by: Tzanko Matev <[email protected]>

Author: tzanko-matev

README.md

@@ -54,7 +54,7 @@ Line-aware stdout/stderr capture proxies are now enabled by default. Control the
 
 - CLI: `python -m codetracer_python_recorder --io-capture=off script.py` disables capture, while `--io-capture=proxies+fd` also mirrors raw file-descriptor writes.
 - Python: `configure_policy(io_capture_line_proxies=False)` toggles proxies, and `configure_policy(io_capture_fd_fallback=True)` enables the FD fallback.
-- Environment: set `CODETRACER_CAPTURE_IO=off`, `proxies`, or `proxies,fd` to match the CLI and Python helpers.
+- Environment: set `CODETRACER_CAPTURE_IO=off`, `proxies`, or `proxies+fd` (`,` is also accepted) to match the CLI and Python helpers.
 
 ### Migration checklist for downstream tools
 

codetracer-python-recorder/Cargo.lock

@@ -31,6 +31,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 uuid = { version = "1.10", features = ["v4"] }
 recorder-errors = { version = "0.1.0", path = "crates/recorder-errors" }
+libc = "0.2"
 
 [dev-dependencies]
 pyo3 = { version = "0.25.1", features = ["auto-initialize"] }

codetracer-python-recorder/Cargo.toml

@@ -251,7 +251,7 @@ fn parse_capture_io(value: &str) -> RecorderResult<(bool, bool)> {
 
     let mut line_proxies = false;
     let mut fd_fallback = false;
-    for token in lower.split(',') {
+    for token in lower.split(|c| matches!(c, ',' | '+')) {
         match token.trim() {
             "" => {}
             "proxies" | "proxy" => line_proxies = true,
@@ -460,6 +460,22 @@ mod tests {
         reset_policy();
     }
 
+    #[test]
+    fn configure_policy_from_env_accepts_plus_separator() {
+        reset_policy();
+        let env_guard = env_lock();
+        env::set_var(ENV_CAPTURE_IO, "proxies+fd");
+
+        configure_policy_from_env().expect("configure from env with plus separator");
+
+        drop(env_guard);
+
+        let snap = policy_snapshot();
+        assert!(snap.io_capture.line_proxies);
+        assert!(snap.io_capture.fd_fallback);
+        reset_policy();
+    }
+
     #[test]
     fn configure_policy_from_env_rejects_invalid_boolean() {
         reset_policy();