vaadin/flow 24.9.18 on GitHub

Changes since 24.9.17

Prevent deadlock on concurrent push and disconnect (CP: 25.0) (#24216) (CP: 24.9)
Commit · Pull request
This PR cherry-picks changes from the original PR #24216 to branch 24.9. --- #### Original PR description > The previous AtomicBoolean guard in AtmospherePushConnection closed only the disconnect-vs-disconnect race. A push thread that reads disconnecting as false before a concurrent disconnect() flips it can still proceed into synchronized(lock) behind the disconnect thread, which is itself blocked inside resource.close() waiting for the servlet container's HTTP session lock held by the push thread — a two-lock cycle. > > Move resource.close() out of the monitor: inside synchronized(lock) capture the resource into a local and call connectionLost() to transition the state, then release the monitor before invoking close() on the stashed reference. Add a matching re-check of isConnected() at the top of the synchronized block in push() so a push that waited for the monitor observes the late disconnect and defers via PUSH_PENDING/RESPONSE_PENDING instead of NPEing on the cleared resource. The disconnecting flag stays set until close() returns so subsequent pushes take the fast path and no new disconnect() re-enters while close() is still in flight. > > Related-to #24192 > ---------