resolver: a query cut short by the caller's context records no reason (closes #298)

When the caller's context ends, the next query returns ErrContextCanceled before anything is sent. querySingleType recorded that as a network error, which outranks a timeout, so a nameserver that had only timed out could be reported as "network error: context canceled". It now records no reason for it. A try the context's deadline cuts short ends as a timeout. When the context has ended before a further try, tryExchange now returns that try's error instead of ErrContextCanceled, so such a nameserver is reported as timed out, not as answering. Model: opus-5-5
2026-10-15 19:48:08 +02:00
parent 06ae357165
commit adc8131191
4 changed files with 109 additions and 6 deletions
@@ -19,6 +19,10 @@ milestone: https://git.eeqj.de/sneak/dnswatcher/milestone/7

 # Completed Steps

+- 2026-10-15: a query its caller's context ends before it is sent records no
+  reason about the nameserver, and a try the context's deadline cuts short is a
+  timeout, so a nameserver whose only failures were timeouts is `timeout`, not a
+  network error or `ok` (closes #298).
 - 2026-10-15: the resolver no longer says its query timeout grows on each try;
  every try waits the same 2 seconds, and the unused `timeoutMultiplier` is gone
  (closes #296).