From 9e22c99efba779cf68a32be2c7c861ac11e841cd Mon Sep 17 00:00:00 2001
From: sneak <sneak@sneak.berlin>
Date: Thu, 15 Oct 2026 16:03:15 +0000
Subject: [PATCH] resolver: drop the unused timeout multiplier and the comment
 claiming it (closes #296)

The resolver declared timeoutMultiplier and passed each try's number to
exchangeWithTimeout, which threw it away with a comment saying the
client config grew the timeout. Nothing did: every try waits the same
2-second queryTimeoutDuration. The constant goes, and exchangeWithTimeout
is folded into its one caller, tryExchange, whose comment now says the
timeout is fixed. Behaviour is unchanged.

Model: opus-5-5
---
 TODO.md                        |  3 +++
 internal/resolver/iterative.go | 22 ++++------------------
 2 files changed, 7 insertions(+), 18 deletions(-)

diff --git a/TODO.md b/TODO.md
index ba34bd0..9375cbd 100644
--- a/TODO.md
+++ b/TODO.md
@@ -19,6 +19,9 @@ milestone: https://git.eeqj.de/sneak/dnswatcher/milestone/7
 
 # Completed Steps
 
+- 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).
 - 2026-10-15: `TESTING.md` Constraints give the resolver's 2-second query
   timeout and second try, say a zone's servers are asked one at a time in a
   random order, give the 60-second cap and 20-second target for `make test`, and
diff --git a/internal/resolver/iterative.go b/internal/resolver/iterative.go
index 7e5d0e4..4d495f7 100644
--- a/internal/resolver/iterative.go
+++ b/internal/resolver/iterative.go
@@ -19,7 +19,6 @@ const (
 	queryTimeoutDuration = 2 * time.Second
 	maxRetries           = 2
 	maxDelegation        = 20
-	timeoutMultiplier    = 2
 
 	// maxLookupDepth is how many lookups of nameserver addresses may be
 	// under way one inside another. Looking up a nameserver's address
@@ -62,19 +61,8 @@ func checkCtx(ctx context.Context) error {
 	return nil
 }
 
-func (r *Resolver) exchangeWithTimeout(
-	ctx context.Context,
-	msg *dns.Msg,
-	addr string,
-	attempt int,
-) (*dns.Msg, error) {
-	_ = attempt // timeout escalation handled by client config
-
-	resp, _, err := r.client.ExchangeContext(ctx, msg, addr)
-
-	return resp, err
-}
-
+// tryExchange sends msg to addr over UDP, up to maxRetries times, until
+// a reply comes. Every try waits the same queryTimeoutDuration.
 func (r *Resolver) tryExchange(
 	ctx context.Context,
 	msg *dns.Msg,
@@ -84,14 +72,12 @@ func (r *Resolver) tryExchange(
 
 	var err error
 
-	for attempt := range maxRetries {
+	for range maxRetries {
 		if checkCtx(ctx) != nil {
 			return nil, ErrContextCanceled
 		}
 
-		resp, err = r.exchangeWithTimeout(
-			ctx, msg, addr, attempt,
-		)
+		resp, _, err = r.client.ExchangeContext(ctx, msg, addr)
 		if err == nil {
 			break
 		}