[MM-38375] Fix processing bulk import with attachments (#18352)

* Fix improper attachments in replies

* Fix import data path

* Improve errors

* Fix importing attachments directly from zip file

* Add some test cases to cover error paths

app/import_functions.go

@@ -565,13 +565,22 @@ func (a *App) importUser(data *UserImportData, dryRun bool) *model.AppError {
 	}
 
 	if data.ProfileImage != nil {
-		file, err := os.Open(*data.ProfileImage)
+		var file io.ReadCloser
+		var err error
+		if data.ProfileImageData != nil {
+			file, err = data.ProfileImageData.Open()
+		} else {
+			file, err = os.Open(*data.ProfileImage)
+		}
+
 		if err != nil {
 			mlog.Warn("Unable to open the profile image.", mlog.Err(err))
-		}
-		defer file.Close()
-		if err == nil {
-			if err := a.SetProfileImageFromMultiPartFile(savedUser.Id, file); err != nil {
+		} else {
+			defer file.Close()
+			if limitErr := checkImageLimits(file, *a.Config().FileSettings.MaxImageResolution); limitErr != nil {
+				return model.NewAppError("SetProfileImage", "api.user.upload_profile_user.check_image_limits.app_error", nil, "", http.StatusBadRequest)
+			}
+			if err := a.SetProfileImageFromFile(savedUser.Id, file); err != nil {
 				mlog.Warn("Unable to set the profile image from a file.", mlog.Err(err))
 			}
 		}
@@ -1804,7 +1813,12 @@ func (a *App) importEmoji(data *EmojiImportData, dryRun bool) *model.AppError {
 		emoji.PreSave()
 	}
 
-	file, err := os.Open(*data.Image)
+	var file io.ReadCloser
+	if data.Data != nil {
+		file, err = data.Data.Open()
+	} else {
+		file, err = os.Open(*data.Image)
+	}
 	if err != nil {
 		return model.NewAppError("BulkImport", "app.import.emoji.bad_file.error", map[string]interface{}{"EmojiName": *data.Name}, "", http.StatusBadRequest)
 	}