KTOR-5850 Fix SendCountExceedException in HttpRequestRetry

ktor-client/ktor-client-core/common/src/io/ktor/client/plugins/HttpRequestRetry.kt

@@ -325,6 +325,11 @@ public val HttpRequestRetry: ClientPlugin<HttpRequestRetryConfig> = createClient
         return subRequest
     }
 
+    onRequest { request, _ ->
+        val maxRetriesValue = request.attributes.getOrNull(MaxRetriesPerRequestAttributeKey) ?: maxRetries
+        request.attributes.put(MaxRetriesPerRequestAttributeKey, maxRetriesValue)
+    }
+
     on(Send) { request ->
         var retryCount = 0
         val shouldRetry = request.attributes.getOrNull(ShouldRetryPerRequestAttributeKey) ?: shouldRetry
@@ -376,8 +381,8 @@ public val HttpRequestRetry: ClientPlugin<HttpRequestRetryConfig> = createClient
 }
 
 /**
- * A context for [HttpRequestRetry.Configuration.shouldRetry]
- * and [HttpRequestRetry.Configuration.shouldRetryOnException]
+ * A context for [HttpRequestRetryConfig.shouldRetry]
+ * and [HttpRequestRetryConfig.shouldRetryOnException]
  *
  * [Report a problem](https://ktor.io/feedback/?fqname=io.ktor.client.plugins.HttpRetryShouldRetryContext)
  */
@@ -389,7 +394,7 @@ public class HttpRetryShouldRetryContext(
 )
 
 /**
- * A context for [HttpRequestRetry.Configuration.delayMillis].
+ * A context for [HttpRequestRetryConfig.delayMillis].
  * Contains a non-null [response] or [cause] but not both.
  *
  * [Report a problem](https://ktor.io/feedback/?fqname=io.ktor.client.plugins.HttpRetryDelayContext)
@@ -401,7 +406,7 @@ public class HttpRetryDelayContext internal constructor(
 )
 
 /**
- * A context for [HttpRequestRetry.Configuration.modifyRequest].
+ * A context for [HttpRequestRetryConfig.modifyRequest].
  * Contains a non-null [response] or [cause] but not both.
  *
  * [Report a problem](https://ktor.io/feedback/?fqname=io.ktor.client.plugins.HttpRetryModifyRequestContext)
@@ -445,8 +450,7 @@ public fun HttpRequestBuilder.retry(block: HttpRequestRetryConfig.() -> Unit) {
     attributes.put(ModifyRequestPerRequestAttributeKey, configuration.modifyRequest)
 }
 
-private val MaxRetriesPerRequestAttributeKey =
-    AttributeKey<Int>("MaxRetriesPerRequestAttributeKey")
+internal val MaxRetriesPerRequestAttributeKey = AttributeKey<Int>("MaxRetriesPerRequestAttributeKey")
 
 private val ShouldRetryPerRequestAttributeKey =
     AttributeKey<HttpRetryShouldRetryContext.(HttpRequest, HttpResponse) -> Boolean>(

ktor-client/ktor-client-core/common/src/io/ktor/client/plugins/HttpSend.kt

@@ -11,7 +11,7 @@ import io.ktor.http.*
 import io.ktor.http.content.*
 import io.ktor.util.*
 import io.ktor.utils.io.*
-import kotlinx.coroutines.*
+import kotlinx.coroutines.cancel
 
 /**
  * HttpSend pipeline interceptor function
@@ -89,8 +89,13 @@ public class HttpSend private constructor(
                         .trimMargin()
                 }
                 context.setBody(content)
-
-                val realSender: Sender = DefaultSender(plugin.maxSendCount, scope)
+                val maxRetriesFromRetryPlugin = context.attributes.getOrNull(MaxRetriesPerRequestAttributeKey)
+                val maxRetries = if (maxRetriesFromRetryPlugin != null) {
+                    maxRetriesFromRetryPlugin + 1 // +1 for the initial request
+                } else {
+                    plugin.maxSendCount
+                }
+                val realSender: Sender = DefaultSender(maxRetries, scope)
                 var interceptedSender = realSender
                 for (interceptor in plugin.interceptors.reversed()) {
                     interceptedSender = InterceptedSender(interceptor, interceptedSender)

ktor-client/ktor-client-tests/common/test/io/ktor/client/tests/HttpRequestRetryTest.kt

@@ -516,4 +516,35 @@ class HttpRequestRetryTest {
             assertEquals(HttpStatusCode.OK, response.status)
         }
     }
+
+    @Test
+    fun testRetryHasPriorityOverHttpSend() = testWithEngine(MockEngine) {
+        val maxRetriesCount = 5
+        var counter = 1
+        config {
+            engine {
+                addHandler {
+                    if (counter < maxRetriesCount) {
+                        counter++
+                        respondError(HttpStatusCode.InternalServerError)
+                    } else {
+                        respondOk()
+                    }
+                }
+            }
+
+            install(HttpRequestRetry) {
+                retryOnServerErrors(maxRetriesCount)
+                delayMillis { 0L }
+            }
+            install(HttpSend) {
+                maxSendCount = 1
+            }
+        }
+
+        test { client ->
+            assertEquals(HttpStatusCode.OK, client.get("/").status)
+            assertEquals(maxRetriesCount, counter)
+        }
+    }
 }