Extract rollout into its own crate (#15548)

codex-rs/utils/path-utils/src/env.rs

@@ -0,0 +1,46 @@
+//! Functions for environment detection that need to be shared across crates.
+
+fn env_var_set(key: &str) -> bool {
+    std::env::var(key).is_ok_and(|v| !v.trim().is_empty())
+}
+
+/// Returns true if the current process is running under Windows Subsystem for Linux.
+pub fn is_wsl() -> bool {
+    #[cfg(target_os = "linux")]
+    {
+        if std::env::var_os("WSL_DISTRO_NAME").is_some() {
+            return true;
+        }
+        match std::fs::read_to_string("/proc/version") {
+            Ok(version) => version.to_lowercase().contains("microsoft"),
+            Err(_) => false,
+        }
+    }
+    #[cfg(not(target_os = "linux"))]
+    {
+        false
+    }
+}
+
+/// Returns true when Codex is likely running in an environment without a usable GUI.
+///
+/// This is intentionally conservative and is used by frontends to avoid flows that would try to
+/// open a browser (e.g. device-code auth fallback).
+pub fn is_headless_environment() -> bool {
+    if env_var_set("CI")
+        || env_var_set("SSH_CONNECTION")
+        || env_var_set("SSH_CLIENT")
+        || env_var_set("SSH_TTY")
+    {
+        return true;
+    }
+
+    #[cfg(target_os = "linux")]
+    {
+        if !env_var_set("DISPLAY") && !env_var_set("WAYLAND_DISPLAY") {
+            return true;
+        }
+    }
+
+    false
+}