several one-line panic, race, and logic fixes (#7766)

app/auto_posts.go

@@ -44,6 +44,9 @@ func (cfg *AutoPostCreator) UploadTestFile() ([]string, bool) {
 
 	path, _ := utils.FindDir("web/static/images")
 	file, err := os.Open(path + "/" + filename)
+	if err != nil {
+		return nil, false
+	}
 	defer file.Close()
 
 	data := &bytes.Buffer{}

app/channel.go

@@ -1185,7 +1185,7 @@ func (a *App) ViewChannel(view *model.ChannelView, userId string, clearPushNotif
 		}
 	}
 
-	times := map[string]int64{}
+	var times map[string]int64
 	if result := <-uchan; result.Err != nil {
 		return nil, result.Err
 	} else {

app/file.go

@@ -259,10 +259,10 @@ func (a *App) UploadFiles(teamId string, channelId string, userId string, fileHe
 
 	for i, fileHeader := range fileHeaders {
 		file, fileErr := fileHeader.Open()
-		defer file.Close()
 		if fileErr != nil {
 			return nil, model.NewAppError("UploadFiles", "api.file.upload_file.bad_parse.app_error", nil, fileErr.Error(), http.StatusBadRequest)
 		}
+		defer file.Close()
 
 		buf := bytes.NewBuffer(nil)
 		io.Copy(buf, file)

app/saml.go

@@ -36,10 +36,10 @@ func WriteSamlFile(fileData *multipart.FileHeader) *model.AppError {
 	}
 
 	file, err := fileData.Open()
-	defer file.Close()
 	if err != nil {
 		return model.NewAppError("AddSamlCertificate", "api.admin.add_certificate.open.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
+	defer file.Close()
 
 	configDir, _ := utils.FindDir("config")
 	out, err := os.Create(configDir + filename)

app/user.go

@@ -774,10 +774,10 @@ func (a *App) GetProfileImage(user *model.User) ([]byte, bool, *model.AppError)
 
 func (a *App) SetProfileImage(userId string, imageData *multipart.FileHeader) *model.AppError {
 	file, err := imageData.Open()
-	defer file.Close()
 	if err != nil {
 		return model.NewAppError("SetProfileImage", "api.user.upload_profile_user.open.app_error", nil, err.Error(), http.StatusBadRequest)
 	}
+	defer file.Close()
 
 	// Decode image config first to check dimensions before loading the whole thing into memory later on
 	config, _, err := image.DecodeConfig(file)