improve error checking (caddyserver#1938)

Author: arxdsilva

assets_test.go

@@ -25,9 +25,15 @@ func TestAssetsPath(t *testing.T) {
 		t.Errorf("Expected path to be a .caddy folder, got: %v", actual)
 	}
 
-	os.Setenv("CADDYPATH", "testpath")
+	err := os.Setenv("CADDYPATH", "testpath")
+	if err != nil {
+		t.Error("Could not set CADDYPATH")
+	}
 	if actual, expected := AssetsPath(), "testpath"; actual != expected {
 		t.Errorf("Expected path to be %v, got: %v", expected, actual)
 	}
-	os.Setenv("CADDYPATH", "")
+	err = os.Setenv("CADDYPATH", "")
+	if err != nil {
+		t.Error("Could not set CADDYPATH")
+	}
 }

caddy.go

@@ -206,12 +206,15 @@ func (i *Instance) Restart(newCaddyfile Input) (*Instance, error) {
 
 	// success! stop the old instance
 	for _, shutdownFunc := range i.onShutdown {
-		err := shutdownFunc()
+		err = shutdownFunc()
 		if err != nil {
 			return i, err
 		}
 	}
-	i.Stop()
+	err = i.Stop()
+	if err != nil {
+		return i, err
+	}
 
 	// Execute instantiation events
 	EmitEvent(InstanceStartupEvent, newInst)
@@ -483,14 +486,14 @@ func startWithListenerFds(cdyfile Input, inst *Instance, restartFds map[string]r
 	if !IsUpgrade() && restartFds == nil {
 		// first startup means not a restart or upgrade
 		for _, firstStartupFunc := range inst.onFirstStartup {
-			err := firstStartupFunc()
+			err = firstStartupFunc()
 			if err != nil {
 				return err
 			}
 		}
 	}
 	for _, startupFunc := range inst.onStartup {
-		err := startupFunc()
+		err = startupFunc()
 		if err != nil {
 			return err
 		}
@@ -653,15 +656,21 @@ func startServers(serverList []Server, inst *Instance, restartFds map[string]res
 				if fdIndex, ok := loadedGob.ListenerFds["tcp"+addr]; ok {
 					file := os.NewFile(fdIndex, "")
 					ln, err = net.FileListener(file)
-					file.Close()
+					if err != nil {
+						return err
+					}
+					err = file.Close()
 					if err != nil {
 						return err
 					}
 				}
 				if fdIndex, ok := loadedGob.ListenerFds["udp"+addr]; ok {
 					file := os.NewFile(fdIndex, "")
 					pc, err = net.FilePacketConn(file)
-					file.Close()
+					if err != nil {
+						return err
+					}
+					err = file.Close()
 					if err != nil {
 						return err
 					}
@@ -684,7 +693,10 @@ func startServers(serverList []Server, inst *Instance, restartFds map[string]res
 					if err != nil {
 						return err
 					}
-					file.Close()
+					err = file.Close()
+					if err != nil {
+						return err
+					}
 				}
 				// packetconn
 				if old.packet != nil {
@@ -696,7 +708,10 @@ func startServers(serverList []Server, inst *Instance, restartFds map[string]res
 					if err != nil {
 						return err
 					}
-					file.Close()
+					err = file.Close()
+					if err != nil {
+						return err
+					}
 				}
 			}
 		}

upgrade.go

@@ -136,15 +136,21 @@ func Upgrade() error {
 
 	// immediately close our dup'ed fds and the write end of our signal pipe
 	for _, f := range extraFiles {
-		f.Close()
+		err = f.Close()
+		if err != nil {
+			return err
+		}
 	}
 
 	// feed Caddyfile to the child
 	err = gob.NewEncoder(wpipe).Encode(cdyfileGob)
 	if err != nil {
 		return err
 	}
-	wpipe.Close()
+	err = wpipe.Close()
+	if err != nil {
+		return err
+	}
 
 	// determine whether child startup succeeded
 	answer, readErr := ioutil.ReadAll(sigrpipe)