[gdb/dap] Join JSON writer thread with DAP thread
The DAP interpreter runs in its own thread, and starts a few threads:
- the JSON reader thread,
- the JSON writer thread, and
- the inferior output reader thread.
As part of the DAP shutdown, both the JSON reader thread and the JSON writer
thread, as well as the DAP main thread run to exit, but these exits are not
ordered in any way.
Wait in the main DAP thread for the exit of the JSON writer thread.
This makes sure that the responses are flushed to the DAP client before DAP
shutdown.
An earlier version of this patch used Queue.task_done() to accomplish the
same, but that didn't guarantee writing the "<thread name>: terminating"
log entry from thread_wrapper before DAP shutdown.
Tested on aarch64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
PR dap/31380
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31380
diff --git a/gdb/python/lib/gdb/dap/io.py b/gdb/python/lib/gdb/dap/io.py
index 4edd504..81e835c 100644
--- a/gdb/python/lib/gdb/dap/io.py
+++ b/gdb/python/lib/gdb/dap/io.py
@@ -79,4 +79,4 @@
stream.write(body_bytes)
stream.flush()
- start_thread("JSON writer", _json_writer)
+ return start_thread("JSON writer", _json_writer)
diff --git a/gdb/python/lib/gdb/dap/server.py b/gdb/python/lib/gdb/dap/server.py
index 7cc5a46..e711066 100644
--- a/gdb/python/lib/gdb/dap/server.py
+++ b/gdb/python/lib/gdb/dap/server.py
@@ -212,7 +212,7 @@
# Before looping, start the thread that writes JSON to the
# client, and the thread that reads output from the inferior.
start_thread("output reader", self._read_inferior_output)
- start_json_writer(self.out_stream, self.write_queue)
+ json_writer = start_json_writer(self.out_stream, self.write_queue)
start_thread("JSON reader", self._reader_thread)
while not self.done:
cmd = self.read_queue.get()
@@ -229,6 +229,7 @@
# JSON-writing thread, so that we can ensure that all
# responses are flushed to the client before exiting.
self.write_queue.put(None)
+ json_writer.join()
@in_dap_thread
def send_event_later(self, event, body=None):
diff --git a/gdb/python/lib/gdb/dap/startup.py b/gdb/python/lib/gdb/dap/startup.py
index 6049121..0a42c91 100644
--- a/gdb/python/lib/gdb/dap/startup.py
+++ b/gdb/python/lib/gdb/dap/startup.py
@@ -80,6 +80,7 @@
result = gdb.Thread(name=name, target=thread_wrapper, args=args, daemon=True)
result.start()
+ return result
def start_dap(target):
