From 3a66395756ba3b599ae3e54d9c5250f576827e79 Mon Sep 17 00:00:00 2001
From: Jesse Wilson <jesse@swank.ca>
Date: Sat, 25 Jul 2026 13:46:10 -0400
Subject: [PATCH 1/2] Cache empty results on the failure schedule.

---
 .../okhttp3/internal/dns/RealDnsCache.kt      |  7 ++-
 .../internal/dns/StateMachineDnsCallTest.kt   | 61 +++++++++++++++++++
 2 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt
index eb95b73a5cf3..99ad1885ec52 100644
--- a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt
+++ b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt
@@ -204,10 +204,11 @@ class RealDnsCache(
       while (true) {
         val previous = entry.state.get()
         val sentAt = previous.inFlightCall!!.sentAt
-        val timeToLive =
-          (dnsResponse.answers.minOfOrNull { it.timeToLive } ?: 0)
-            .seconds
+        val timeToLive = when {
+          dnsResponse.answers.isEmpty() -> failureTimeToLive
+          else -> dnsResponse.answers.minOf { it.timeToLive }.seconds
             .coerceIn(minimumTimeToLive, maximumTimeToLive)
+        }
         val revalidateDelay = (timeToLive - revalidateBeforeExpire).coerceAtLeast(0.seconds)
 
         val next =
diff --git a/okhttp/src/commonTest/kotlin/okhttp3/internal/dns/StateMachineDnsCallTest.kt b/okhttp/src/commonTest/kotlin/okhttp3/internal/dns/StateMachineDnsCallTest.kt
index 13d2f94bd31c..0871a2aef844 100644
--- a/okhttp/src/commonTest/kotlin/okhttp3/internal/dns/StateMachineDnsCallTest.kt
+++ b/okhttp/src/commonTest/kotlin/okhttp3/internal/dns/StateMachineDnsCallTest.kt
@@ -738,6 +738,67 @@ class StateMachineDnsCallTest {
       assertThat(cache.hitCount).isEqualTo(0)
     }
 
+  @Test
+  fun `empty result expires on the same schedule as failure`() =
+    testStateMachineDnsCall {
+      val call0 =
+        newCall(
+          request = Dns.Request(hostname = "lysine.dev"),
+          caching = true,
+          includeIPv6 = false,
+          includeServiceMetadata = false,
+        )
+      call0.enqueue()
+      queryFactory.respondToQuery(
+        hostname = "lysine.dev",
+        type = TYPE_A,
+        addresses = listOf(),
+      )
+      call0.takeOnRecordsIpAddresses(
+        last = true,
+        addresses = listOf(),
+      )
+
+      // The empty result is still cached.
+      val call1 =
+        newCall(
+          request = Dns.Request(hostname = "lysine.dev"),
+          caching = true,
+          includeIPv6 = false,
+          includeServiceMetadata = false,
+        )
+      call1.enqueue()
+      call1.takeOnRecordsIpAddresses(
+        last = true,
+        addresses = listOf(),
+      )
+
+      // The empty result expires after 5 seconds.
+      sleep(5.seconds)
+      val call2 =
+        newCall(
+          request = Dns.Request(hostname = "lysine.dev"),
+          caching = true,
+          includeIPv6 = false,
+          includeServiceMetadata = false,
+        )
+      call2.enqueue()
+      queryFactory.respondToQuery(
+        hostname = "lysine.dev",
+        type = TYPE_A,
+        addresses = blueIpv4s,
+      )
+      call2.takeOnRecordsIpAddresses(
+        last = true,
+        addresses = blueIpv4s,
+      )
+
+      assertThat(cache.size).isEqualTo(1)
+      assertThat(cache.requestCount).isEqualTo(3)
+      assertThat(cache.networkCount).isEqualTo(2)
+      assertThat(cache.hitCount).isEqualTo(1)
+    }
+
   @Test
   fun `failure is revalidated`() =
     testStateMachineDnsCall {

From 48ff0962a31f07440241650d3a6d9a8775942f05 Mon Sep 17 00:00:00 2001
From: Jesse Wilson <jesse@swank.ca>
Date: Sat, 25 Jul 2026 17:56:37 -0400
Subject: [PATCH 2/2] Spotless

---
 .../okhttp3/internal/dns/RealDnsCache.kt       | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt
index 99ad1885ec52..bbf46d1abe66 100644
--- a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt
+++ b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/dns/RealDnsCache.kt
@@ -204,11 +204,19 @@ class RealDnsCache(
       while (true) {
         val previous = entry.state.get()
         val sentAt = previous.inFlightCall!!.sentAt
-        val timeToLive = when {
-          dnsResponse.answers.isEmpty() -> failureTimeToLive
-          else -> dnsResponse.answers.minOf { it.timeToLive }.seconds
-            .coerceIn(minimumTimeToLive, maximumTimeToLive)
-        }
+        val timeToLive =
+          when {
+            dnsResponse.answers.isEmpty() -> {
+              failureTimeToLive
+            }
+
+            else -> {
+              dnsResponse.answers
+                .minOf { it.timeToLive }
+                .seconds
+                .coerceIn(minimumTimeToLive, maximumTimeToLive)
+            }
+          }
         val revalidateDelay = (timeToLive - revalidateBeforeExpire).coerceAtLeast(0.seconds)
 
         val next =