[TS] Implement near-heap-limit termination

crates/core/src/config.rs

@@ -185,8 +185,12 @@ pub struct V8HeapPolicyConfig {
     pub heap_gc_trigger_fraction: f64,
     #[serde(default = "def_retire", deserialize_with = "de_fraction")]
     pub heap_retire_fraction: f64,
-    #[serde(default, rename = "heap-limit-mb", deserialize_with = "de_limit_mb")]
-    pub heap_limit_bytes: Option<usize>,
+    #[serde(
+        default = "def_heap_limit",
+        rename = "heap-limit-mb",
+        deserialize_with = "de_limit_mb"
+    )]
+    pub heap_limit_bytes: usize,
 }
 
 impl Default for V8HeapPolicyConfig {
@@ -196,7 +200,7 @@ impl Default for V8HeapPolicyConfig {
             heap_check_time_interval: def_time_interval(),
             heap_gc_trigger_fraction: def_gc_trigger(),
             heap_retire_fraction: def_retire(),
-            heap_limit_bytes: None,
+            heap_limit_bytes: def_heap_limit(),
         }
     }
 }
@@ -237,6 +241,12 @@ fn def_retire() -> f64 {
     0.75
 }
 
+/// Default heap limit, in bytes
+fn def_heap_limit() -> usize {
+    // 1 GiB
+    1024 * 1024 * 1024
+}
+
 fn de_nz_u64<'de, D>(deserializer: D) -> Result<Option<u64>, D::Error>
 where
     D: serde::Deserializer<'de>,
@@ -289,22 +299,20 @@ where
     }
 }
 
-fn de_limit_mb<'de, D>(deserializer: D) -> Result<Option<usize>, D::Error>
+fn de_limit_mb<'de, D>(deserializer: D) -> Result<usize, D::Error>
 where
     D: serde::Deserializer<'de>,
 {
     let value = u64::deserialize(deserializer)?;
     if value == 0 {
-        return Ok(None);
+        return Ok(def_heap_limit());
     }
 
     let bytes = value
         .checked_mul(1024 * 1024)
         .ok_or_else(|| serde::de::Error::custom("heap-limit-mb is too large"))?;
 
-    usize::try_from(bytes)
-        .map(Some)
-        .map_err(|_| serde::de::Error::custom("heap-limit-mb does not fit in usize"))
+    usize::try_from(bytes).map_err(|_| serde::de::Error::custom("heap-limit-mb does not fit in usize"))
 }
 
 #[cfg(test)]
@@ -420,7 +428,7 @@ mod tests {
         );
         assert_eq!(config.v8_heap_policy.heap_gc_trigger_fraction, 0.67);
         assert_eq!(config.v8_heap_policy.heap_retire_fraction, 0.75);
-        assert_eq!(config.v8_heap_policy.heap_limit_bytes, None);
+        assert_eq!(config.v8_heap_policy.heap_limit_bytes, 1024 * 1024 * 1024);
     }
 
     #[test]
@@ -443,6 +451,6 @@ mod tests {
         );
         assert_eq!(config.v8_heap_policy.heap_gc_trigger_fraction, 0.6);
         assert_eq!(config.v8_heap_policy.heap_retire_fraction, 0.8);
-        assert_eq!(config.v8_heap_policy.heap_limit_bytes, Some(256 * 1024 * 1024));
+        assert_eq!(config.v8_heap_policy.heap_limit_bytes, 256 * 1024 * 1024);
     }
 }

crates/core/src/host/v8/error.rs

@@ -217,7 +217,7 @@ pub(crate) struct ExceptionThrown {
 
 impl ExceptionThrown {
     /// Turns a caught JS exception in `scope` into a [`JSError`].
-    pub(crate) fn into_error(self, scope: &mut PinTryCatch) -> JsError {
+    pub(crate) fn into_error(self, scope: &mut PinTryCatch) -> Result<JsError, UnknownJsError> {
         JsError::from_caught(scope)
     }
 }
@@ -254,12 +254,15 @@ pub(super) enum ErrorOrException<Exc> {
     Exception(Exc),
 }
 
-impl<Exc> ErrorOrException<Exc> {
-    pub(super) fn map_exception<Exc2>(self, f: impl FnOnce(Exc) -> Exc2) -> ErrorOrException<Exc2> {
-        match self {
+impl ErrorOrException<ExceptionThrown> {
+    pub(super) fn exc_into_error(
+        self,
+        scope: &mut PinTryCatch<'_, '_, '_, '_>,
+    ) -> Result<ErrorOrException<JsError>, UnknownJsError> {
+        Ok(match self {
             ErrorOrException::Err(e) => ErrorOrException::Err(e),
-            ErrorOrException::Exception(exc) => ErrorOrException::Exception(f(exc)),
-        }
+            ErrorOrException::Exception(exc) => ErrorOrException::Exception(exc.into_error(scope)?),
+        })
     }
 }
 
@@ -275,6 +278,12 @@ impl From<ExceptionThrown> for ErrorOrException<ExceptionThrown> {
     }
 }
 
+impl From<JsError> for ErrorOrException<JsError> {
+    fn from(e: JsError) -> Self {
+        Self::Exception(e)
+    }
+}
+
 impl From<ErrorOrException<JsError>> for anyhow::Error {
     fn from(err: ErrorOrException<JsError>) -> Self {
         match err {
@@ -528,23 +537,41 @@ fn get_or_insert_slot<T: 'static>(isolate: &mut v8::Isolate, default: impl FnOnc
 
 impl JsError {
     /// Turns a caught JS exception in `scope` into a [`JSError`].
-    fn from_caught(scope: &mut PinTryCatch<'_, '_, '_, '_>) -> Self {
-        match scope.message() {
-            Some(message) => Self {
-                trace: message
-                    .get_stack_trace(scope)
-                    .map(|trace| JsStackTrace::from_trace(scope, trace))
-                    .unwrap_or_default(),
-                msg: message.get(scope).to_rust_string_lossy(scope),
-            },
-            None => Self {
-                trace: JsStackTrace::default(),
-                msg: "unknown error".to_owned(),
-            },
+    fn from_caught(scope: &mut PinTryCatch<'_, '_, '_, '_>) -> Result<Self, UnknownJsError> {
+        let message = scope.message().ok_or(UnknownJsError)?;
+        Ok(Self {
+            trace: message
+                .get_stack_trace(scope)
+                .map(|trace| JsStackTrace::from_trace(scope, trace))
+                .unwrap_or_default(),
+            msg: message.get(scope).to_rust_string_lossy(scope),
+        })
+    }
+}
+
+pub(super) struct UnknownJsError;
+
+impl From<UnknownJsError> for JsError {
+    fn from(_: UnknownJsError) -> Self {
+        Self {
+            trace: JsStackTrace::default(),
+            msg: "unknown error".to_owned(),
         }
     }
 }
 
+impl From<UnknownJsError> for ErrorOrException<JsError> {
+    fn from(e: UnknownJsError) -> Self {
+        Self::Exception(e.into())
+    }
+}
+
+impl From<UnknownJsError> for anyhow::Error {
+    fn from(e: UnknownJsError) -> Self {
+        JsError::from(e).into()
+    }
+}
+
 pub(super) fn log_traceback(replica_ctx: &ReplicaContext, func_type: &str, func: &str, e: &anyhow::Error) {
     log::info!("{func_type} \"{func}\" runtime error: {e:}");
     if let Some(js_err) = e.downcast_ref::<JsError>() {
@@ -573,7 +600,7 @@ pub(super) fn catch_exception<'scope, T>(
     body: impl FnOnce(&mut PinTryCatch<'scope, '_, '_, '_>) -> Result<T, ErrorOrException<ExceptionThrown>>,
 ) -> Result<T, ErrorOrException<JsError>> {
     tc_scope!(scope, scope);
-    body(scope).map_err(|e| e.map_exception(|exc| exc.into_error(scope)))
+    body(scope).map_err(|e| e.exc_into_error(scope).unwrap_or_else(Into::into))
 }
 
 pub(super) type PinTryCatch<'scope, 'iso, 'x, 's> = PinnedRef<'x, TryCatch<'s, 'scope, HandleScope<'iso>>>;