Add static analyzer to discourage use of panic() (#15075)

* Implement static analysis to prevent panics

* Add nopanic to nogo

* Fix violations and add exclusions

Fix violations and add exclusions for all

* Changelog fragment

* Use pass.Report instead of pass.Reportf

* Remove strings.ToLower for checking init method name

* Add exclusion for herumi init

* Move api/client/beacon template function to init and its own file

* Fix nopanic testcase

cmd/beacon-chain/main.go

@@ -180,7 +180,7 @@ func before(ctx *cli.Context) error {
 		f := joonix.NewFormatter()
 
 		if err := joonix.DisableTimestampFormat(f); err != nil {
-			panic(err)
+			panic(err) // lint:nopanic -- This shouldn't happen, but crashing immediately at startup is OK.
 		}
 
 		logrus.SetFormatter(f)
@@ -250,7 +250,7 @@ func main() {
 	defer func() {
 		if x := recover(); x != nil {
 			log.Errorf("Runtime panic: %v\n%v", x, string(runtimeDebug.Stack()))
-			panic(x)
+			panic(x) // lint:nopanic -- This is just resurfacing the original panic.
 		}
 	}()
 

cmd/client-stats/main.go

@@ -69,7 +69,7 @@ func main() {
 		case "fluentd":
 			f := joonix.NewFormatter()
 			if err := joonix.DisableTimestampFormat(f); err != nil {
-				panic(err)
+				panic(err) // lint:nopanic -- This shouldn't happen, but crashing immediately at startup is OK.
 			}
 			logrus.SetFormatter(f)
 		case "json":
@@ -94,7 +94,7 @@ func main() {
 	defer func() {
 		if x := recover(); x != nil {
 			log.Errorf("Runtime panic: %v\n%v", x, string(runtimeDebug.Stack()))
-			panic(x)
+			panic(x) // lint:nopanic -- This is just resurfacing the original panic.
 		}
 	}()
 

cmd/prysmctl/p2p/client.go

@@ -90,7 +90,7 @@ func newClient(beaconEndpoints []string, tcpPort, quicPort uint) (*client, error
 
 func (c *client) Close() {
 	if err := c.host.Close(); err != nil {
-		panic(err)
+		panic(err) // lint:nopanic -- The client is closing anyway...
 	}
 }
 
@@ -193,7 +193,7 @@ func (c *client) initializeMockChainService(ctx context.Context) (*mockChain, er
 func ipAddr() net.IP {
 	ip, err := network.ExternalIP()
 	if err != nil {
-		panic(err)
+		panic(err) // lint:nopanic -- Only returns an error when network interfaces are not available. This is a requirement for the application anyway.
 	}
 	return net.ParseIP(ip)
 }

cmd/prysmctl/p2p/peers.go

@@ -14,7 +14,7 @@ func (c *client) connectToPeers(ctx context.Context, peerMultiaddrs ...string) e
 	}
 	addrInfos, err := peer.AddrInfosFromP2pAddrs(peers...)
 	if err != nil {
-		panic(err)
+		return err
 	}
 	for _, info := range addrInfos {
 		if info.ID == c.host.ID() {

cmd/validator/main.go

@@ -163,7 +163,7 @@ func main() {
 			case "fluentd":
 				f := joonix.NewFormatter()
 				if err := joonix.DisableTimestampFormat(f); err != nil {
-					panic(err)
+					panic(err) // lint:nopanic -- This shouldn't happen, but crashing immediately at startup is OK.
 				}
 				logrus.SetFormatter(f)
 			case "json":
@@ -208,7 +208,7 @@ func main() {
 	defer func() {
 		if x := recover(); x != nil {
 			log.Errorf("Runtime panic: %v\n%v", x, string(runtimeDebug.Stack()))
-			panic(x)
+			panic(x) // lint:nopanic -- This is just resurfacing the original panic.
 		}
 	}()
 

cmd/wrap_flags.go

@@ -34,11 +34,11 @@ func WrapFlags(flags []cli.Flag) []cli.Flag {
 			f = altsrc.NewPathFlag(t)
 		case *cli.Int64Flag:
 			// Int64Flag does not work. See https://github.com/prysmaticlabs/prysm/issues/6478
-			panic(fmt.Sprintf("unsupported flag type %T", f))
+			panic(fmt.Sprintf("unsupported flag type %T", f)) // lint:nopanic -- This is evaluated at application start.
 		case *cli.IntSliceFlag:
 			f = altsrc.NewIntSliceFlag(t)
 		default:
-			panic(fmt.Sprintf("cannot convert type %T", f))
+			panic(fmt.Sprintf("cannot convert type %T", f)) // lint:nopanic -- This is evaluated at application start.
 		}
 		wrapped = append(wrapped, f)
 	}