Add bidirectional test flow by Shourya742 · Pull Request #21479 · rust-lang/rust-analyzer

Shourya742 · 2026-01-15T19:56:23Z

This PR extends the proc-macro integration test suite to cover the bidirectional Postcard protocol flow.

Veykril · 2026-01-18T08:59:18Z

why are the line endings changed in this file?

Veykril · 2026-01-18T09:01:52Z

-            // IO error from server is expected when client disconnects
-            if matches!(
-                e.kind(),
-                io::ErrorKind::BrokenPipe
-                    | io::ErrorKind::UnexpectedEof
-                    | io::ErrorKind::InvalidData
-            ) {
-                panic!("Server error: {e}");
-            }
-        }
-        Err(e) => std::panic::resume_unwind(e),
-    }
-
-    result
-}
-
-/// Sends a request and reads the response using JSON protocol.
-pub(crate) fn request(
-    writer: &mut dyn Write,
-    reader: &mut dyn BufRead,
-    request: Request,
-) -> Response {
-    request.write::<JsonProtocol>(writer).expect("failed to write request");
-
-    let mut buf = String::new();
-    Response::read::<JsonProtocol>(reader, &mut buf)
-        .expect("failed to read response")
-        .expect("no response received")
-}
-
-/// Creates a simple empty token tree suitable for testing.
-pub(crate) fn create_empty_token_tree(
-    version: u32,
-    span_data_table: &mut SpanDataIndexMap,
-) -> FlatTree {
-    let anchor = SpanAnchor {
-        file_id: EditionedFileId::new(FileId::from_raw(0), Edition::CURRENT),
-        ast_id: span::ROOT_ERASED_FILE_AST_ID,
-    };
-    let span = Span {
-        range: TextRange::empty(0.into()),
-        anchor,
-        ctx: SyntaxContext::root(Edition::CURRENT),
-    };
-
-    let builder = TopSubtreeBuilder::new(Delimiter {
-        open: span,
-        close: span,
-        kind: DelimiterKind::Invisible,
-    });
-    let tt = builder.build();
-
-    FlatTree::from_subtree(tt.view(), version, span_data_table)
-}
+use std::{
+    collections::VecDeque,
+    io::{self, BufRead, Read, Write},
+    sync::{Arc, Condvar, Mutex},
+    thread,
+};
+
+use paths::Utf8PathBuf;
+use proc_macro_api::{
+    ServerError,
+    bidirectional_protocol::msg::{
+        BidirectionalMessage, Request as BiRequest, Response as BiResponse, SubRequest, SubResponse,
+    },
+    legacy_protocol::msg::{FlatTree, Message, Request, Response, SpanDataIndexMap},
+    transport::codec::{json::JsonProtocol, postcard::PostcardProtocol},
+};
+use span::{Edition, EditionedFileId, FileId, Span, SpanAnchor, SyntaxContext, TextRange};
+use tt::{Delimiter, DelimiterKind, TopSubtreeBuilder};
+
+/// Shared state for an in-memory byte channel.
+#[derive(Default)]
+struct ChannelState {
+    buffer: VecDeque<u8>,
+    closed: bool,
+}
+
+type InMemoryChannel = Arc<(Mutex<ChannelState>, Condvar)>;
+
+/// Writer end of an in-memory channel.
+pub(crate) struct ChannelWriter {
+    state: InMemoryChannel,
+}
+
+impl Write for ChannelWriter {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let (lock, cvar) = &*self.state;
+        let mut state = lock.lock().unwrap();
+        if state.closed {
+            return Err(io::Error::new(io::ErrorKind::BrokenPipe, "channel closed"));
+        }
+        state.buffer.extend(buf);
+        cvar.notify_all();
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Drop for ChannelWriter {
+    fn drop(&mut self) {
+        let (lock, cvar) = &*self.state;
+        let mut state = lock.lock().unwrap();
+        state.closed = true;
+        cvar.notify_all();
+    }
+}
+
+/// Reader end of an in-memory channel.
+pub(crate) struct ChannelReader {
+    state: InMemoryChannel,
+    internal_buf: Vec<u8>,
+}
+
+impl Read for ChannelReader {
+    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        let (lock, cvar) = &*self.state;
+        let mut state = lock.lock().unwrap();
+
+        while state.buffer.is_empty() && !state.closed {
+            state = cvar.wait(state).unwrap();
+        }
+
+        if state.buffer.is_empty() && state.closed {
+            return Ok(0);
+        }
+
+        let to_read = buf.len().min(state.buffer.len());
+        for (dst, src) in buf.iter_mut().zip(state.buffer.drain(..to_read)) {
+            *dst = src;
+        }
+        Ok(to_read)
+    }
+}
+
+impl BufRead for ChannelReader {
+    fn fill_buf(&mut self) -> io::Result<&[u8]> {
+        let (lock, cvar) = &*self.state;
+        let mut state = lock.lock().unwrap();
+
+        while state.buffer.is_empty() && !state.closed {
+            state = cvar.wait(state).unwrap();
+        }
+
+        self.internal_buf.clear();
+        self.internal_buf.extend(&state.buffer);
+        Ok(&self.internal_buf)
+    }
+
+    fn consume(&mut self, amt: usize) {
+        let (lock, _) = &*self.state;
+        let mut state = lock.lock().unwrap();
+        let to_drain = amt.min(state.buffer.len());
+        drop(state.buffer.drain(..to_drain));
+    }
+}
+
+/// Creates a connected pair of channels for bidirectional communication.
+fn create_channel_pair() -> (ChannelWriter, ChannelReader, ChannelWriter, ChannelReader) {
+    // Channel for client -> server communication
+    let client_to_server = Arc::new((
+        Mutex::new(ChannelState { buffer: VecDeque::new(), closed: false }),
+        Condvar::new(),
+    ));
+    let client_writer = ChannelWriter { state: client_to_server.clone() };
+    let server_reader = ChannelReader { state: client_to_server, internal_buf: Vec::new() };
+
+    // Channel for server -> client communication
+    let server_to_client = Arc::new((
+        Mutex::new(ChannelState { buffer: VecDeque::new(), closed: false }),
+        Condvar::new(),
+    ));
+
+    let server_writer = ChannelWriter { state: server_to_client.clone() };
+    let client_reader = ChannelReader { state: server_to_client, internal_buf: Vec::new() };
+
+    (client_writer, client_reader, server_writer, server_reader)
+}
+
+pub(crate) fn proc_macro_test_dylib_path() -> Utf8PathBuf {
+    let path = proc_macro_test::PROC_MACRO_TEST_LOCATION;
+    if path.is_empty() {
+        panic!("proc-macro-test dylib not available (requires nightly toolchain)");
+    }
+    path.into()
+}
+
+/// Creates a simple empty token tree suitable for testing.
+pub(crate) fn create_empty_token_tree(
+    version: u32,
+    span_data_table: &mut SpanDataIndexMap,
+) -> FlatTree {
+    let anchor = SpanAnchor {
+        file_id: EditionedFileId::new(FileId::from_raw(0), Edition::CURRENT),
+        ast_id: span::ROOT_ERASED_FILE_AST_ID,
+    };
+    let span = Span {
+        range: TextRange::empty(0.into()),
+        anchor,
+        ctx: SyntaxContext::root(Edition::CURRENT),
+    };
+
+    let builder = TopSubtreeBuilder::new(Delimiter {
+        open: span,
+        close: span,
+        kind: DelimiterKind::Invisible,
+    });
+    let tt = builder.build();
+
+    FlatTree::from_subtree(tt.view(), version, span_data_table)
+}
+
+pub(crate) fn with_server<F, R>(format: proc_macro_api::ProtocolFormat, test_fn: F) -> R
+where
+    F: FnOnce(&mut dyn Write, &mut dyn BufRead) -> R,
+{
+    let (mut client_writer, mut client_reader, mut server_writer, mut server_reader) =
+        create_channel_pair();
+
+    let server_handle = thread::spawn(move || {
+        proc_macro_srv_cli::main_loop::run(&mut server_reader, &mut server_writer, format)
+    });
+
+    let result = test_fn(&mut client_writer, &mut client_reader);
+
+    drop(client_writer);
+
+    match server_handle.join() {
+        Ok(Ok(())) => {}
+        Ok(Err(e)) => {
+            if !matches!(


why this change?

Thats sus... I am not sure why line change happened although locally on my editor I am seeing the diff clearly.

Though the lines are the same(nothing changed at all). I recently enable auto formatting on save, but not sure if that's the culprit.

…inition

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jan 15, 2026

Veykril reviewed Jan 18, 2026

View reviewed changes

Shourya742 force-pushed the 2026-01-15-add-bidirectional-test-flow branch 9 times, most recently from fb4a580 to 97178c8 Compare January 18, 2026 14:53

Shourya742 requested a review from Veykril January 18, 2026 15:19

Shourya742 added 6 commits January 19, 2026 12:33

remove non-describing field annotation from bidirectional message def…

dae5430

…inition

remove serialize from Expn Globals

c6398b0

add bidirectional flow

33191a9

add bidirectional test

7ad02d3

adapt json test

20bbc61

rename send and drive to request and receive and remove auto*

06fb5a7

Shourya742 force-pushed the 2026-01-15-add-bidirectional-test-flow branch from 8adeaba to 06fb5a7 Compare January 19, 2026 07:04

Veykril approved these changes Jan 24, 2026

View reviewed changes

Veykril added this pull request to the merge queue Jan 24, 2026

Merged via the queue into rust-lang:master with commit 5dc1579 Jan 24, 2026
15 checks passed

rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jan 24, 2026

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Add bidirectional test flow#21479

Add bidirectional test flow#21479
Veykril merged 6 commits into
rust-lang:masterfrom
Shourya742:2026-01-15-add-bidirectional-test-flow

Shourya742 commented Jan 15, 2026

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Veykril Jan 18, 2026

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Shourya742 commented Jan 15, 2026

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Veykril Jan 18, 2026

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