From 18bcf46fad1cbb41d43275a6d7154555492136c2 Mon Sep 17 00:00:00 2001
From: Mathias Fussenegger <f.mathias@zignar.net>
Date: Sat, 16 Nov 2024 10:51:03 +0100
Subject: [PATCH] Fix race between stopped thread retrieval and continued event

If the debug adapter sends continued right after stopped, before the
client retrieved the threads the continued change was lost.

Should fix https://github.com/mfussenegger/nvim-dap/issues/1365
---
 lua/dap/session.lua       | 15 ++++++++++++++-
 spec/integration_spec.lua | 26 ++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/lua/dap/session.lua b/lua/dap/session.lua
index fcfe9861..3b2aca03 100644
--- a/lua/dap/session.lua
+++ b/lua/dap/session.lua
@@ -657,7 +657,8 @@ function Session:update_threads(cb)
       threads[thread.id] = thread
       local old_thread = self.threads[thread.id]
       if old_thread then
-        thread.stopped = old_thread.stopped
+        local stopped = old_thread.stopped == nil and false or old_thread.stopped
+        thread.stopped = stopped
         thread.frames = old_thread.frames
       end
     end
@@ -689,12 +690,24 @@ function Session:event_stopped(stopped)
     local co = coroutine.running()
 
     if self.dirty.threads or (stopped.threadId and self.threads[stopped.threadId] == nil) then
+      local thread = {
+        id = stopped.threadId,
+        name = "Unknown",
+        stopped = true
+      }
+      if thread.id then
+        self.threads[thread.id] = thread
+      end
       self:update_threads(coresume(co))
       local err = coroutine.yield()
       if err then
         utils.notify('Error retrieving threads: ' .. utils.fmt_error(err), vim.log.levels.ERROR)
         return
       end
+      if thread.stopped == false then
+        log.debug("Thread resumed during stopped event handling", stopped, thread)
+        return
+      end
     end
 
     local should_jump = stopped.reason ~= 'pause' or stopped.allThreadsStopped
diff --git a/spec/integration_spec.lua b/spec/integration_spec.lua
index 1f0b9cd8..2e83bd76 100644
--- a/spec/integration_spec.lua
+++ b/spec/integration_spec.lua
@@ -322,6 +322,32 @@ describe('dap with fake server', function()
     })
   end)
 
+  it("Doesn't jump on stopped if continue is received before threads response", function()
+    run_and_wait_until_initialized(config, server)
+    server.client.threads = function(self, request)
+      self:send_event("continued", {
+        threadId = 1,
+      })
+      self:send_response(request, {
+        threads = { { id = 1, name = 'thread1' }, }
+      })
+    end
+    local log = require('dap.log').create_logger('dap.log')
+    local debug = log.debug
+    local messages = {}
+    log.debug = function(...)
+      table.insert(messages, {...})
+      debug(...)
+    end
+    server.client:send_event('stopped', {
+      threadId = 1,
+      reason = 'unknown',
+    })
+    wait_for_response(server, "threads")
+    wait(function() return #messages >= 5 end)
+    assert.are.same("Thread resumed during stopped event handling", messages[6][1])
+  end)
+
   it("Clears stopped state on continued event", function()
     local buf = api.nvim_create_buf(true, false)
     local win = api.nvim_get_current_win()