multi: don't access loop variables in goroutines

This commit makes sure that no loop variables or other temporary
variables are accessed directly in a goroutine but are instead passed
into the goroutine through a parameter. This makes sure a copy of the
value is put on the stack and is not changed while the outside loop
continues.

chainntnfs/bitcoindnotify/bitcoind.go

@@ -235,7 +235,9 @@ out:
 				//
 				// TODO(wilmer): add retry logic if rescan fails?
 				b.wg.Add(1)
-				go func() {
+
+				//nolint:lll
+				go func(msg *chainntnfs.HistoricalConfDispatch) {
 					defer b.wg.Done()
 
 					confDetails, _, err := b.historicalConfDetails(
@@ -269,7 +271,7 @@ out:
 							"details of %v: %v",
 							msg.ConfRequest, err)
 					}
-				}()
+				}(msg)
 
 			case *chainntnfs.HistoricalSpendDispatch:
 				// In order to ensure we don't block the caller
@@ -278,7 +280,9 @@ out:
 				//
 				// TODO(wilmer): add retry logic if rescan fails?
 				b.wg.Add(1)
-				go func() {
+
+				//nolint:lll
+				go func(msg *chainntnfs.HistoricalSpendDispatch) {
 					defer b.wg.Done()
 
 					spendDetails, err := b.historicalSpendDetails(
@@ -320,7 +324,7 @@ out:
 							"details of %v: %v",
 							msg.SpendRequest, err)
 					}
-				}()
+				}(msg)
 
 			case *blockEpochRegistration:
 				chainntnfs.Log.Infof("New block epoch subscription")

chainntnfs/btcdnotify/btcd.go

@@ -347,7 +347,9 @@ out:
 				//
 				// TODO(wilmer): add retry logic if rescan fails?
 				b.wg.Add(1)
-				go func() {
+
+				//nolint:lll
+				go func(msg *chainntnfs.HistoricalConfDispatch) {
 					defer b.wg.Done()
 
 					confDetails, _, err := b.historicalConfDetails(
@@ -372,7 +374,7 @@ out:
 					if err != nil {
 						chainntnfs.Log.Error(err)
 					}
-				}()
+				}(msg)
 
 			case *blockEpochRegistration:
 				chainntnfs.Log.Infof("New block epoch subscription")

chainntnfs/neutrinonotify/neutrino.go

@@ -432,7 +432,9 @@ func (n *NeutrinoNotifier) notificationDispatcher() {
 				// chain asynchronously to prevent blocking
 				// potentially long rescans.
 				n.wg.Add(1)
-				go func() {
+
+				//nolint:lll
+				go func(msg *chainntnfs.HistoricalConfDispatch) {
 					defer n.wg.Done()
 
 					confDetails, err := n.historicalConfDetails(
@@ -457,7 +459,7 @@ func (n *NeutrinoNotifier) notificationDispatcher() {
 					if err != nil {
 						chainntnfs.Log.Error(err)
 					}
-				}()
+				}(msg)
 
 			case *blockEpochRegistration:
 				chainntnfs.Log.Infof("New block epoch subscription")

healthcheck/healthcheck.go

@@ -71,10 +71,11 @@ func (m *Monitor) Start() error {
 		}
 
 		m.wg.Add(1)
-		go func() {
+		go func(check *Observation) {
 			defer m.wg.Done()
+
 			check.monitor(m.cfg.Shutdown, m.quit)
-		}()
+		}(check)
 	}
 
 	return nil

lntest/itest/utils.go

@@ -78,13 +78,12 @@ func completePaymentRequests(client lnrpc.LightningClient,
 	// Launch all payments simultaneously.
 	results := make(chan error)
 	for _, payReq := range paymentRequests {
-		payReqCopy := payReq
-		go func() {
-			err := send(payReqCopy)
+		go func(payReq string) {
+			err := send(payReq)
 			if awaitResponse {
 				results <- err
 			}
-		}()
+		}(payReq)
 	}
 
 	// If awaiting a response, verify that all payments succeeded.

lnwallet/btcwallet/btcwallet.go

@@ -1483,9 +1483,13 @@ out:
 
 			// Launch a goroutine to re-package and send
 			// notifications for any newly confirmed transactions.
-			go func() {
+			//nolint:lll
+			go func(txNtfn *wallet.TransactionNotifications) {
 				for _, block := range txNtfn.AttachedBlocks {
-					details, err := minedTransactionsToDetails(currentHeight, block, t.w.ChainParams())
+					details, err := minedTransactionsToDetails(
+						currentHeight, block,
+						t.w.ChainParams(),
+					)
 					if err != nil {
 						continue
 					}
@@ -1499,11 +1503,11 @@ out:
 					}
 				}
 
-			}()
+			}(txNtfn)
 
 			// Launch a goroutine to re-package and send
 			// notifications for any newly unconfirmed transactions.
-			go func() {
+			go func(txNtfn *wallet.TransactionNotifications) {
 				for _, tx := range txNtfn.UnminedTransactions {
 					detail, err := unminedTransactionsToDetail(
 						tx, t.w.ChainParams(),
@@ -1518,7 +1522,7 @@ out:
 						return
 					}
 				}
-			}()
+			}(txNtfn)
 		case <-t.quit:
 			break out
 		}

rpcserver.go

@@ -5214,7 +5214,7 @@ sendLoop:
 			// payment so we can continue to serve requests while
 			// this payment is being dispatched.
 			wg.Add(1)
-			go func() {
+			go func(payIntent *rpcPaymentIntent) {
 				defer wg.Done()
 
 				// Attempt to grab a free semaphore slot, using
@@ -5292,7 +5292,7 @@ sendLoop:
 					}
 					return
 				}
-			}()
+			}(payIntent)
 		}
 	}