fix(protocol): enforce request IDs and params

conformance/fixtures/v1/03-request-before-initialize.json

@@ -1,10 +1,12 @@
 {
   "name": "request-before-initialize",
-  "description": "No method except lpp/initialize may be processed before the handshake.",
+  "description": "Lifecycle errors take precedence over params validation before the handshake.",
   "scope": "protocol",
   "steps": [
     {"request":{"id":1,"method":"lpp/check","params":{"documents":{}}},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"notInitialized"}}}}}},
-    {"request":{"id":2,"method":"lpp/initialize","params":{"protocolVersion":"1.0"}},"expectResponse":{"result":{"protocolVersion":"1.0","serverInfo":{"name":{"$provider":"nonEmptyString"},"version":{"$provider":"nonEmptyString"}},"languages":{"$provider":"languageList"},"capabilities":{"check":{"$provider":"boolean"},"compile":{"$provider":"boolean"},"reconstruct":{"$provider":"boolean"},"symbols":{"$provider":"boolean"},"definition":{"$provider":"boolean"},"references":{"$provider":"boolean"},"rename":{"$provider":"boolean"},"editValidation":{"$provider":"boolean"}}}}},
-    {"request":{"id":3,"method":"lpp/shutdown","params":{}},"expectResponse":{"result":null}}
+    {"request":{"id":2,"method":"lpp/check"},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"notInitialized"}}}}}},
+    {"request":{"id":3,"method":"lpp/check","params":[]},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"notInitialized"}}}}}},
+    {"request":{"id":4,"method":"lpp/initialize","params":{"protocolVersion":"1.0"}},"expectResponse":{"result":{"protocolVersion":"1.0","serverInfo":{"name":{"$provider":"nonEmptyString"},"version":{"$provider":"nonEmptyString"}},"languages":{"$provider":"languageList"},"capabilities":{"check":{"$provider":"boolean"},"compile":{"$provider":"boolean"},"reconstruct":{"$provider":"boolean"},"symbols":{"$provider":"boolean"},"definition":{"$provider":"boolean"},"references":{"$provider":"boolean"},"rename":{"$provider":"boolean"},"editValidation":{"$provider":"boolean"}}}}},
+    {"request":{"id":5,"method":"lpp/shutdown","params":{}},"expectResponse":{"result":null}}
   ]
 }

conformance/fixtures/v1/04-initialize-twice.json

@@ -5,6 +5,8 @@
   "steps": [
     {"request":{"id":1,"method":"lpp/initialize","params":{"protocolVersion":"1.0"}},"expectResponse":{"result":{"protocolVersion":"1.0","serverInfo":{"name":{"$provider":"nonEmptyString"},"version":{"$provider":"nonEmptyString"}},"languages":{"$provider":"languageList"},"capabilities":{"check":{"$provider":"boolean"},"compile":{"$provider":"boolean"},"reconstruct":{"$provider":"boolean"},"symbols":{"$provider":"boolean"},"definition":{"$provider":"boolean"},"references":{"$provider":"boolean"},"rename":{"$provider":"boolean"},"editValidation":{"$provider":"boolean"}}}}},
     {"request":{"id":2,"method":"lpp/initialize","params":{"protocolVersion":"1.0"}},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"alreadyInitialized"}}}}}},
-    {"request":{"id":3,"method":"lpp/shutdown","params":{}},"expectResponse":{"result":null}}
+    {"request":{"id":3,"method":"lpp/initialize"},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"alreadyInitialized"}}}}}},
+    {"request":{"id":4,"method":"lpp/initialize","params":[]},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"alreadyInitialized"}}}}}},
+    {"request":{"id":5,"method":"lpp/shutdown","params":{}},"expectResponse":{"result":null}}
   ]
 }

conformance/fixtures/v1/08-notification-not-supported.json

@@ -1,9 +1,10 @@
 {
   "name": "notification-not-supported",
-  "description": "LPP v1 defines no notifications: a message without an id is a protocol violation answered with an LPP invalidRequest error (id null in the response).",
+  "description": "LPP v1 defines no notifications: a missing or null id is a protocol violation answered with an LPP invalidRequest error (id null in the response).",
   "scope": "protocol",
   "steps": [
     {"request":{"method":"lpp/shutdown"},"expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"notificationNotSupported"}}}}}},
+    {"rawLine":"{\"jsonrpc\":\"2.0\",\"id\":null,\"method\":\"lpp/shutdown\",\"params\":{}}","expectResponse":{"error":{"code":-32000,"message":{"$provider":"nonEmptyString"},"data":{"lpp":{"kind":"invalidRequest","details":{"reason":"notificationNotSupported"}}}}}},
     {"request":{"id":1,"method":"lpp/initialize","params":{"protocolVersion":"1.0"}},"expectResponse":{"result":{"protocolVersion":"1.0","serverInfo":{"name":{"$provider":"nonEmptyString"},"version":{"$provider":"nonEmptyString"}},"languages":{"$provider":"languageList"},"capabilities":{"check":{"$provider":"boolean"},"compile":{"$provider":"boolean"},"reconstruct":{"$provider":"boolean"},"symbols":{"$provider":"boolean"},"definition":{"$provider":"boolean"},"references":{"$provider":"boolean"},"rename":{"$provider":"boolean"},"editValidation":{"$provider":"boolean"}}}}},
     {"request":{"id":2,"method":"lpp/shutdown","params":{}},"expectResponse":{"result":null}}
   ]

conformance/fixtures/v1/68-invalid-request-id-types.json

@@ -0,0 +1,11 @@
+{
+  "name": "invalid-request-id-types",
+  "description": "A non-null request id must be an integer or string; other JSON values receive standard -32600 with a null response id.",
+  "scope": "protocol",
+  "steps": [
+    {"rawLine":"{\"jsonrpc\":\"2.0\",\"id\":1.5,\"method\":\"lpp/shutdown\",\"params\":{}}","expectResponse":{"error":{"code":-32600,"message":{"$provider":"nonEmptyString"}}}},
+    {"rawLine":"{\"jsonrpc\":\"2.0\",\"id\":true,\"method\":\"lpp/shutdown\",\"params\":{}}","expectResponse":{"error":{"code":-32600,"message":{"$provider":"nonEmptyString"}}}},
+    {"rawLine":"{\"jsonrpc\":\"2.0\",\"id\":[1],\"method\":\"lpp/shutdown\",\"params\":{}}","expectResponse":{"error":{"code":-32600,"message":{"$provider":"nonEmptyString"}}}},
+    {"rawLine":"{\"jsonrpc\":\"2.0\",\"id\":{},\"method\":\"lpp/shutdown\",\"params\":{}}","expectResponse":{"error":{"code":-32600,"message":{"$provider":"nonEmptyString"}}}}
+  ]
+}

conformance/fixtures/v1/69-required-object-params.json

@@ -0,0 +1,12 @@
+{
+  "name": "required-object-params",
+  "description": "Every request requires an object-valued params field; missing or non-object params receive -32602.",
+  "scope": "protocol",
+  "steps": [
+    {"request":{"id":1,"method":"lpp/initialize","params":{"protocolVersion":"1.0","clientInfo":{"name":"wright","version":"0.2.0"}}},"expectResponse":{"result":{"protocolVersion":"1.0","serverInfo":{"name":{"$provider":"nonEmptyString"},"version":{"$provider":"nonEmptyString"}},"languages":{"$provider":"languageList"},"capabilities":{"check":{"$provider":"boolean"},"compile":{"$provider":"boolean"},"reconstruct":{"$provider":"boolean"},"symbols":{"$provider":"boolean"},"definition":{"$provider":"boolean"},"references":{"$provider":"boolean"},"rename":{"$provider":"boolean"},"editValidation":{"$provider":"boolean"}}}}},
+    {"request":{"id":2,"method":"lpp/shutdown"},"expectResponse":{"error":{"code":-32602,"message":{"$provider":"nonEmptyString"}}}},
+    {"request":{"id":3,"method":"lpp/shutdown","params":[]},"expectResponse":{"error":{"code":-32602,"message":{"$provider":"nonEmptyString"}}}},
+    {"request":{"id":4,"method":"lpp/shutdown","params":null},"expectResponse":{"error":{"code":-32602,"message":{"$provider":"nonEmptyString"}}}},
+    {"request":{"id":5,"method":"lpp/shutdown","params":{}},"expectResponse":{"result":null}}
+  ]
+}

conformance/fixtures/v1/70-large-integer-request-ids.json

@@ -0,0 +1,15 @@
+{
+  "name": "large-integer-request-ids",
+  "description": "Integer request ids outside the signed and unsigned 64-bit ranges are accepted and echoed exactly.",
+  "scope": "protocol",
+  "steps": [
+    {
+      "request": {"id": 18446744073709551616, "method": "lpp/shutdown", "params": {}},
+      "expectResponse": {"error": {"code": -32000, "message": {"$provider": "nonEmptyString"}, "data": {"lpp": {"kind": "invalidRequest", "details": {"reason": "notInitialized"}}}}}
+    },
+    {
+      "request": {"id": -9223372036854775809, "method": "lpp/shutdown", "params": {}},
+      "expectResponse": {"error": {"code": -32000, "message": {"$provider": "nonEmptyString"}, "data": {"lpp": {"kind": "invalidRequest", "details": {"reason": "notInitialized"}}}}}
+    }
+  ]
+}

conformance/mock-provider/Cargo.toml

@@ -11,7 +11,7 @@ publish = false
 lpp-conformance-common = { path = "../common" }
 sha2 = "0.10"
 serde = { workspace = true, features = ["derive"] }
-serde_json.workspace = true
+serde_json = { workspace = true, features = ["arbitrary_precision"] }
 
 [lints]
 workspace = true

conformance/mock-provider/src/server.rs

@@ -44,6 +44,12 @@ fn invalid_request() -> Value {
     std_error(Value::Null, -32600, "Invalid Request")
 }
 
+fn is_integer_number(number: &serde_json::Number) -> bool {
+    let number = number.to_string();
+    let digits = number.strip_prefix('-').unwrap_or(&number);
+    !digits.is_empty() && digits.bytes().all(|byte| byte.is_ascii_digit())
+}
+
 /// `invalidRequest`/`notInitialized` for any method called pre-`initialize`.
 fn not_initialized(id: &Value) -> Value {
     lpp_error(
@@ -54,6 +60,15 @@ fn not_initialized(id: &Value) -> Value {
     )
 }
 
+fn already_initialized(id: &Value) -> Value {
+    lpp_error(
+        id.clone(),
+        "invalidRequest",
+        json!({ "reason": "alreadyInitialized" }),
+        "invalid request: already initialized",
+    )
+}
+
 /// Mark `name` disabled for `--without`. Returns false for unknown names.
 pub(crate) fn disable_capability(disabled: &mut HashSet<&'static str>, name: &str) -> bool {
     match CAPABILITIES.iter().find(|(n, _)| *n == name) {
@@ -125,19 +140,33 @@ impl Server {
             return invalid_request();
         };
         let id = match object.get("id") {
-            Some(id @ (Value::Number(_) | Value::String(_))) => id.clone(),
-            // No notifications in LPP v1: a message without an id (or with a
-            // null id) is a protocol violation.
-            _ => {
+            Some(id @ Value::String(_)) => id.clone(),
+            Some(Value::Number(number)) if is_integer_number(number) => {
+                Value::Number(number.clone())
+            }
+            // No notifications in LPP v1: a missing or null id is a protocol
+            // violation, distinct from an invalid non-null id.
+            None | Some(Value::Null) => {
                 return lpp_error(
                     Value::Null,
                     "invalidRequest",
                     json!({ "reason": "notificationNotSupported" }),
                     "invalid request: LPP v1 defines no notifications",
                 );
             }
+            Some(_) => return invalid_request(),
+        };
+        if method == "lpp/initialize" {
+            if self.initialized {
+                return already_initialized(&id);
+            }
+        } else if !self.initialized {
+            return not_initialized(&id);
+        }
+        let params = match object.get("params") {
+            Some(params) if params.is_object() => params.clone(),
+            _ => return std_error(id, -32602, "Invalid params"),
         };
-        let params = object.get("params").cloned().unwrap_or_else(|| json!({}));
         match method {
             "lpp/initialize" => self.initialize(&id, params),
             "lpp/shutdown" => self.shutdown(&id),
@@ -146,14 +175,6 @@ impl Server {
     }
 
     fn initialize(&mut self, id: &Value, params: Value) -> Value {
-        if self.initialized {
-            return lpp_error(
-                id.clone(),
-                "invalidRequest",
-                json!({ "reason": "alreadyInitialized" }),
-                "invalid request: already initialized",
-            );
-        }
         let params: InitParams = match parse_params(params) {
             Ok(params) => params,
             Err(_) => return std_error(id.clone(), -32602, "Invalid params"),
@@ -187,17 +208,11 @@ impl Server {
     }
 
     fn shutdown(&mut self, id: &Value) -> Value {
-        if !self.initialized {
-            return not_initialized(id);
-        }
         self.exiting = true;
         ok(id.clone(), Value::Null)
     }
 
     fn dispatch(&mut self, id: &Value, method: &str, params: Value) -> Value {
-        if !self.initialized {
-            return not_initialized(id);
-        }
         let Some(entry) = METHODS.iter().find(|m| m.name == method) else {
             return std_error(id.clone(), -32601, "Method not found");
         };
@@ -215,3 +230,91 @@ impl Server {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn server() -> Server {
+        Server::new(DEFAULT_PROTOCOL_VERSION.to_string(), HashSet::new())
+    }
+
+    #[test]
+    fn invalid_non_null_request_ids_are_invalid_requests() {
+        let mut server = server();
+        for request in [
+            r#"{"jsonrpc":"2.0","id":1.5,"method":"lpp/shutdown","params":{}}"#,
+            r#"{"jsonrpc":"2.0","id":true,"method":"lpp/shutdown","params":{}}"#,
+            r#"{"jsonrpc":"2.0","id":[1],"method":"lpp/shutdown","params":{}}"#,
+            r#"{"jsonrpc":"2.0","id":{},"method":"lpp/shutdown","params":{}}"#,
+        ] {
+            let response = server.handle_message(request);
+            assert_eq!(response["error"]["code"], json!(-32600));
+            assert_eq!(response["id"], Value::Null);
+        }
+    }
+
+    #[test]
+    fn integer_request_ids_larger_than_u64_are_preserved() {
+        let mut server = server();
+        for id in ["18446744073709551616", "-9223372036854775809"] {
+            let request =
+                format!(r#"{{"jsonrpc":"2.0","id":{id},"method":"lpp/shutdown","params":{{}}}}"#);
+            let response = server.handle_message(&request);
+
+            assert_eq!(
+                response["error"]["data"]["lpp"]["details"]["reason"],
+                "notInitialized"
+            );
+            assert_eq!(response["id"].as_number().unwrap().to_string(), id);
+        }
+    }
+
+    #[test]
+    fn missing_and_null_ids_keep_the_notification_error() {
+        let mut server = server();
+        for request in [
+            r#"{"jsonrpc":"2.0","method":"lpp/shutdown","params":{}}"#,
+            r#"{"jsonrpc":"2.0","id":null,"method":"lpp/shutdown","params":{}}"#,
+        ] {
+            let response = server.handle_message(request);
+            assert_eq!(
+                response["error"]["data"]["lpp"]["details"]["reason"],
+                json!("notificationNotSupported")
+            );
+            assert_eq!(response["id"], Value::Null);
+        }
+    }
+
+    #[test]
+    fn params_must_be_present_and_an_object() {
+        let mut server = server();
+        let initialized = server.handle_message(
+            r#"{"jsonrpc":"2.0","id":1,"method":"lpp/initialize","params":{"protocolVersion":"1.0"}}"#,
+        );
+        assert!(initialized.get("result").is_some());
+
+        for (request, id) in [
+            (
+                r#"{"jsonrpc":"2.0","id":2,"method":"lpp/shutdown"}"#,
+                json!(2),
+            ),
+            (
+                r#"{"jsonrpc":"2.0","id":3,"method":"lpp/shutdown","params":[]}"#,
+                json!(3),
+            ),
+            (
+                r#"{"jsonrpc":"2.0","id":4,"method":"lpp/shutdown","params":null}"#,
+                json!(4),
+            ),
+        ] {
+            let response = server.handle_message(request);
+            assert_eq!(response["error"]["code"], json!(-32602));
+            assert_eq!(response["id"], id);
+        }
+
+        let shutdown = server
+            .handle_message(r#"{"jsonrpc":"2.0","id":5,"method":"lpp/shutdown","params":{}}"#);
+        assert_eq!(shutdown["result"], Value::Null);
+    }
+}

conformance/runner/Cargo.toml

@@ -10,7 +10,7 @@ publish = false
 [dependencies]
 lpp-conformance-common = { path = "../common" }
 serde = { workspace = true, features = ["derive"] }
-serde_json.workspace = true
+serde_json = { workspace = true, features = ["arbitrary_precision"] }
 
 [lints]
 workspace = true

docs/spec/transport.md

@@ -48,6 +48,9 @@ rules:
   `details.reason` = `notificationNotSupported`, with `id` null in the
   response. (This is an explicit deviation from JSON-RPC notification
   semantics, chosen so that client mistakes are always observable.)
+* **Invalid ids**: a non-null `id` that is neither an integer nor a string is
+  an invalid request and MUST receive the standard `-32600` error with a null
+  response `id`.
 * **No batches**: clients MUST NOT send batch messages. If a provider receives
   an array message, it MUST respond with the standard JSON-RPC error
   `-32600` ("Invalid Request") and `id` null.
@@ -63,7 +66,7 @@ data attached:
 | Code | Name | When |
 | --- | --- | --- |
 | `-32700` | Parse error | A message line is not valid JSON. Response `id` is null. |
-| `-32600` | Invalid Request | The message is not a valid JSON-RPC request (wrong `jsonrpc` value, missing `method`, non-object message, batch). |
+| `-32600` | Invalid Request | The message is not a valid JSON-RPC request (wrong `jsonrpc` value, missing `method`, invalid non-null `id`, non-object message, batch). |
 | `-32601` | Method not found | The method name is not a known LPP v1 method. |
 | `-32602` | Invalid params | The `params` value does not match the method's schema (wrong types or missing required fields). |
 | `-32603` | Internal error | The provider failed internally. |