Fix connection timeout when retries are set to none

Sources/GRPC/ConnectionBackoff.swift

@@ -99,7 +99,7 @@ public struct ConnectionBackoff: Sequence, Sendable {
 
 /// An iterator for ``ConnectionBackoff``.
 public class ConnectionBackoffIterator: IteratorProtocol {
-  public typealias Element = (timeout: TimeInterval, backoff: TimeInterval)
+  public typealias Element = (timeout: TimeInterval, backoff: TimeInterval?)
 
   /// Creates a new connection backoff iterator with the given configuration.
   public init(connectionBackoff: ConnectionBackoff) {
@@ -135,7 +135,12 @@ public class ConnectionBackoffIterator: IteratorProtocol {
     case let .limited(limit) where limit > 0:
       self.connectionBackoff.retries.limit = .limited(limit - 1)
 
-    // limit must be <= 0, no new element.
+    // limit is reached, return an element with only a timeout.
+    case let .limited(limit) where limit == 0:
+      self.connectionBackoff.retries.limit = .limited(limit - 1)
+      return self.makeElement(backoff: nil)
+
+    // limit must be < 0, no new element.
     case .limited:
       return nil
     }
@@ -159,8 +164,8 @@ public class ConnectionBackoffIterator: IteratorProtocol {
 
   /// Make a timeout-backoff pair from the given backoff. The timeout is the `max` of the backoff
   /// and `connectionBackoff.minimumConnectionTimeout`.
-  private func makeElement(backoff: TimeInterval) -> Element {
-    let timeout = max(backoff, self.connectionBackoff.minimumConnectionTimeout)
+  private func makeElement(backoff: TimeInterval?) -> Element {
+    let timeout = max(backoff ?? self.unjitteredBackoff, self.connectionBackoff.minimumConnectionTimeout)
     return (timeout, backoff)
   }
 

Sources/GRPC/ConnectionManager.swift

@@ -997,7 +997,10 @@ extension ConnectionManager {
     }
 
     // Should we reconnect if the candidate channel fails?
-    let reconnect: Reconnect = timeoutAndBackoff.map { .after($0.backoff) } ?? .none
+    var reconnect = Reconnect.none
+    if let backoff = timeoutAndBackoff?.backoff {
+        reconnect = Reconnect.after(backoff)
+    }
     let connecting = ConnectingState(
       backoffIterator: backoffIterator,
       reconnect: reconnect,

Tests/GRPCTests/ConnectionBackoffTests.swift

@@ -43,7 +43,7 @@ class ConnectionBackoffTests: GRPCTestCase {
         pow(self.backoff.initialBackoff * self.backoff.multiplier, Double(i)),
         self.backoff.maximumBackoff
       )
-      XCTAssertEqual(expected, backoff, accuracy: 1e-6)
+      XCTAssertEqual(expected, backoff!, accuracy: 1e-6)
     }
   }
 
@@ -55,7 +55,7 @@ class ConnectionBackoffTests: GRPCTestCase {
       )
       let halfJitterRange = self.backoff.jitter * unjittered
       let jitteredRange = (unjittered - halfJitterRange) ... (unjittered + halfJitterRange)
-      XCTAssert(jitteredRange.contains(timeoutAndBackoff.backoff))
+      XCTAssert(jitteredRange.contains(timeoutAndBackoff.backoff!))
     }
   }
 
@@ -65,7 +65,7 @@ class ConnectionBackoffTests: GRPCTestCase {
     self.backoff.jitter = 0.0
 
     for backoff in self.backoff.prefix(100).map({ $0.backoff }) {
-      XCTAssertLessThanOrEqual(backoff, self.backoff.maximumBackoff)
+      XCTAssertLessThanOrEqual(backoff!, self.backoff.maximumBackoff)
     }
   }
 
@@ -79,19 +79,19 @@ class ConnectionBackoffTests: GRPCTestCase {
     for limit in [1, 3, 5] {
       let backoff = ConnectionBackoff(retries: .upTo(limit))
       let values = Array(backoff)
-      XCTAssertEqual(values.count, limit)
+      XCTAssertEqual(values.count, limit+1)
     }
   }
 
   func testConnectionBackoffWhenLimitedToZeroRetries() {
     let backoff = ConnectionBackoff(retries: .upTo(0))
     let values = Array(backoff)
-    XCTAssertTrue(values.isEmpty)
+      XCTAssertEqual(values.count, 1)
   }
 
   func testConnectionBackoffWithNoRetries() {
     let backoff = ConnectionBackoff(retries: .none)
     let values = Array(backoff)
-    XCTAssertTrue(values.isEmpty)
+      XCTAssertEqual(values.count, 1)
   }
 }