Fix deep syntax tree bug generated by proc-macro

Cargo.lock

@@ -1182,6 +1182,7 @@ dependencies = [
  "log",
  "serde",
  "serde_json",
+ "serde_stacker",
  "tt",
 ]
 
@@ -1239,6 +1240,15 @@ dependencies = [
  "toolchain",
 ]
 
+[[package]]
+name = "psm"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3abf49e5417290756acfd26501536358560c4a5cc4a0934d390939acb3e7083a"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "pulldown-cmark"
 version = "0.8.0"
@@ -1557,6 +1567,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_stacker"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4c92391a63e3b83f77334d8beaaf11bac4c900f3769483e543bf76a81bf8ee2"
+dependencies = [
+ "serde",
+ "stacker",
+]
+
 [[package]]
 name = "sharded-slab"
 version = "0.1.0"
@@ -1602,6 +1622,19 @@ dependencies = [
  "text_edit",
 ]
 
+[[package]]
+name = "stacker"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21ccb4c06ec57bc82d0f610f1a2963d7648700e43a6f513e564b9c89f7991786"
+dependencies = [
+ "cc",
+ "cfg-if 0.1.10",
+ "libc",
+ "psm",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "stdx"
 version = "0.0.0"

crates/proc_macro_api/Cargo.toml

@@ -12,6 +12,7 @@ doctest = false
 [dependencies]
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+serde_stacker = "0.1"
 log = "0.4.8"
 crossbeam-channel = "0.5.0"
 jod-thread = "0.1.1"

crates/proc_macro_api/src/msg.rs

@@ -58,7 +58,14 @@ pub trait Message: Serialize + DeserializeOwned {
     fn read(inp: &mut impl BufRead) -> io::Result<Option<Self>> {
         Ok(match read_json(inp)? {
             None => None,
-            Some(text) => Some(serde_json::from_str(&text)?),
+            Some(text) => {
+                let mut deserializer = serde_json::Deserializer::from_str(&text);
+                // Note that some proc-macro generate very deep syntax tree
+                // We have to disable the current limit of serde here
+                deserializer.disable_recursion_limit();
+                let deserializer = serde_stacker::Deserializer::new(&mut deserializer);
+                Some(Self::deserialize(deserializer)?)
+            }
         })
     }
     fn write(self, out: &mut impl Write) -> io::Result<()> {

crates/proc_macro_api/src/process.rs

@@ -92,10 +92,11 @@ fn client_loop(task_rx: Receiver<Task>, mut process: Process) {
     for Task { req, result_tx } in task_rx {
         match send_request(&mut stdin, &mut stdout, req) {
             Ok(res) => result_tx.send(res).unwrap(),
-            Err(_err) => {
+            Err(err) => {
                 log::error!(
-                    "proc macro server crashed, server process state: {:?}",
-                    process.child.try_wait()
+                    "proc macro server crashed, server process state: {:?}, server request error: {:?}",
+                    process.child.try_wait(),
+                    err
                 );
                 let res = Response::Error(ResponseError {
                     code: ErrorCode::ServerErrorEnd,