feat(php-rpc): replay Rust-side env writes into the PHP worker

The worker is a long-lived child holding the environment it was handed
at spawn, so `@putenv`, the bin dir the event dispatcher prepends to
PATH, and COMPOSER_DEV_MODE never reached the PHP code running in it.

The shim now journals every write to the three storages PHP exposes, and
the outermost rpc_call replays the entries the worker has not seen yet
through __shirabe_sync_env. Replaying the writes rather than pushing a
whole snapshot keeps the worker's own $_SERVER entries intact.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 51 insertions, 6 deletions

diff --git a/crates/shirabe-php-shim/src/env.rs b/crates/shirabe-php-shim/src/env.rs
index 8facfb4a..861c0243 100644
--- a/crates/shirabe-php-shim/src/env.rs
+++ b/crates/shirabe-php-shim/src/env.rs
@@ -15,6 +15,7 @@ pub fn getenv<K: AsRef<std::ffi::OsStr>>(key: K) -> Option<std::ffi::OsString> {
 /// duration of this call.
 pub unsafe fn putenv<K: AsRef<std::ffi::OsStr>, V: AsRef<std::ffi::OsStr>>(key: K, value: V) {
     // TODO(php-semantics): validate key and value format to avoid panic?
+    record(EnvStorageKind::Process, key.as_ref(), Some(value.as_ref()));
     unsafe { std::env::set_var(key, value) }
 }
 
@@ -25,19 +26,59 @@ pub unsafe fn putenv<K: AsRef<std::ffi::OsStr>, V: AsRef<std::ffi::OsStr>>(key:
 /// duration of this call.
 pub unsafe fn putenv_clear<K: AsRef<std::ffi::OsStr>>(key: K) {
     // TODO(php-semantics): validate key and value format to avoid panic?
+    record(EnvStorageKind::Process, key.as_ref(), None);
     unsafe { std::env::remove_var(key) }
 }
 
+/// Which of the three environment storages a recorded mutation writes to.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum EnvStorageKind {
+    /// The real process environment, as `putenv()` writes it.
+    Process,
+    /// The `$_ENV` superglobal.
+    Env,
+    /// The `$_SERVER` superglobal.
+    Server,
+}
+
+/// One recorded write. `value` is `None` for an unset.
+#[derive(Debug, Clone)]
+pub struct EnvMutation {
+    pub storage: EnvStorageKind,
+    pub key: std::ffi::OsString,
+    pub value: Option<std::ffi::OsString>,
+}
+
+static ENV_MUTATIONS: std::sync::Mutex<Vec<EnvMutation>> = std::sync::Mutex::new(Vec::new());
+
+fn record(storage: EnvStorageKind, key: &std::ffi::OsStr, value: Option<&std::ffi::OsStr>) {
+    ENV_MUTATIONS.lock().unwrap().push(EnvMutation {
+        storage,
+        key: key.to_os_string(),
+        value: value.map(|value| value.to_os_string()),
+    });
+}
+
+/// The mutations recorded after the first `cursor` ones, and the cursor that follows them.
+///
+/// A separate PHP runtime holds the environment it was handed when it started; replaying these
+/// writes in order is what brings its three storages back in line with this process's.
+pub fn env_mutations_since(cursor: usize) -> (usize, Vec<EnvMutation>) {
+    let mutations = ENV_MUTATIONS.lock().unwrap();
+    (mutations.len(), mutations[cursor..].to_vec())
+}
+
 pub struct Superglobal {
+    storage: EnvStorageKind,
     vars: indexmap::IndexMap<std::ffi::OsString, std::ffi::OsString>,
 }
 
 pub struct SuperglobalServer(Superglobal);
 
 impl Superglobal {
-    fn from_env_vars() -> Self {
+    fn from_env_vars(storage: EnvStorageKind) -> Self {
         let vars = std::env::vars_os().collect();
-        Self { vars }
+        Self { storage, vars }
     }
 
     pub fn get_all(&self) -> impl Iterator<Item = (std::ffi::OsString, std::ffi::OsString)> + '_ {
@@ -49,17 +90,19 @@ impl Superglobal {
     }
 
     pub fn put(&mut self, key: std::ffi::OsString, value: std::ffi::OsString) {
+        record(self.storage, &key, Some(&value));
         self.vars.insert(key, value);
     }
 
     pub fn clear<K: AsRef<std::ffi::OsStr>>(&mut self, key: K) {
+        record(self.storage, key.as_ref(), None);
         self.vars.shift_remove(key.as_ref());
     }
 }
 
 impl SuperglobalServer {
     fn from_env_vars() -> Self {
-        Self(Superglobal::from_env_vars())
+        Self(Superglobal::from_env_vars(EnvStorageKind::Server))
     }
 
     pub fn get_all(&self) -> impl Iterator<Item = (std::ffi::OsString, std::ffi::OsString)> + '_ {
@@ -89,12 +132,14 @@ impl SuperglobalServer {
 
 /// PHP superglobal $_SERVER. $_SERVER is a snapshot at startup. Modifying it does not affect the
 /// real environment variables, while putenv() does.
-/// TODO(php-runtime): modify the real PHP's $_SERVER.
+/// TODO(php-runtime): a write PHP code makes to its own $_SERVER is not reflected back here.
 pub static PHP_SERVER: std::sync::LazyLock<std::sync::Mutex<SuperglobalServer>> =
     std::sync::LazyLock::new(|| std::sync::Mutex::new(SuperglobalServer::from_env_vars()));
 
 /// PHP superglobal $_ENV. $_ENV is a snapshot at startup. Modifying it does not affect the real
 /// environment variables, while putenv() does.
-/// TODO(php-runtime): modify the real PHP's $_ENV.
+/// TODO(php-runtime): a write PHP code makes to its own $_ENV is not reflected back here.
 pub static PHP_ENV: std::sync::LazyLock<std::sync::Mutex<Superglobal>> =
-    std::sync::LazyLock::new(|| std::sync::Mutex::new(Superglobal::from_env_vars()));
+    std::sync::LazyLock::new(|| {
+        std::sync::Mutex::new(Superglobal::from_env_vars(EnvStorageKind::Env))
+    });