gnodet opened a new pull request, #1901:
URL: https://github.com/apache/maven-resolver/pull/1901
Fixes #1743
## Problem
The IPC lock tests are increasingly flaky on Windows CI. The root cause is a
protocol-level bug where the server accumulates orphaned waiters and contexts
when clients time out waiting for lock acquisition.
### The race condition
When two threads compete for an exclusive lock via IPC:
1. Thread A acquires the lock, Thread B is added as a waiter on the server
2. B's client-side `CompletableFuture.get(time, unit)` times out →
`doLockExclusively()` returns `false`
3. A unlocks → server promotes B's waiter → server sends RESPONSE_ACQUIRE to
client
4. **But B already moved on** — the response hits a stale/missing entry in
the `responses` map
5. **B's context is never closed** (no REQUEST_CLOSE sent) → server thinks B
holds the lock → corrupted state for subsequent tests
On Windows, higher IPC latency widens the race window significantly.
## Fix
Three targeted changes:
1. **`IpcNamedLock.doLockShared()` / `doLockExclusively()`**: When
`client.lock()` throws `TimeoutException`, send `client.unlock(contextId)` to
clean up the server-side context and waiter before returning `false`.
Previously the context was leaked.
2. **`IpcClient.send()`**: On `TimeoutException`, remove the
`CompletableFuture` from the `responses` map so late server responses don't hit
stale entries.
3. **`IpcClient.receive()`**: When the response map lookup returns `null`
(response arrived for a timed-out request), `continue` gracefully instead of
throwing `IllegalStateException("Protocol error")` and killing the connection.
Re-enabled all three IPC test classes on Windows
(`@DisabledOnOs(OS.WINDOWS)` removed from `IpcAdapterIT`, `IpcAdapterNoForkIT`,
`IpcNamedLockFactoryIT`).
All 32 tests pass consistently.
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