[MM 12458] Include user preferences in bulk export (#9784)

* First version of the preference exporter

* First working version of the preference export

* Removed useless debug line

* Added special case of empty string to harverst the omitempty feature

* Removed dangling line from rebase

* Moved exportablepreference in scope

* Fix go vet issue

* Fix formating

* Add simple test

* Add full test for BulkExportUsers

* Improve variable naming

app/export.go

@@ -15,6 +15,41 @@ import (
 	"github.com/pkg/errors"
 )
 
+// We use this map to identify the exportable preferences.
+// Here we link the preference category and name, to the name of the relevant filed in the import struct.
+var exportablePreferences = map[ComparablePreference]string{{
+	Category: model.PREFERENCE_CATEGORY_THEME,
+	Name:     "",
+}: "Theme", {
+	Category: model.PREFERENCE_CATEGORY_ADVANCED_SETTINGS,
+	Name:     "feature_enabled_markdown_preview",
+}: "UseMarkdownPreview", {
+	Category: model.PREFERENCE_CATEGORY_ADVANCED_SETTINGS,
+	Name:     "formatting",
+}: "UseFormatting", {
+	Category: model.PREFERENCE_CATEGORY_SIDEBAR_SETTINGS,
+	Name:     "show_unread_section",
+}: "ShowUnreadSection", {
+	Category: model.PREFERENCE_CATEGORY_DISPLAY_SETTINGS,
+	Name:     model.PREFERENCE_NAME_USE_MILITARY_TIME,
+}: "UseMilitaryTime", {
+	Category: model.PREFERENCE_CATEGORY_DISPLAY_SETTINGS,
+	Name:     model.PREFERENCE_NAME_COLLAPSE_SETTING,
+}: "CollapsePreviews", {
+	Category: model.PREFERENCE_CATEGORY_DISPLAY_SETTINGS,
+	Name:     model.PREFERENCE_NAME_MESSAGE_DISPLAY,
+}: "MessageDisplay", {
+	Category: model.PREFERENCE_CATEGORY_DISPLAY_SETTINGS,
+	Name:     "channel_display_mode",
+}: "ChannelDisplayMode", {
+	Category: model.PREFERENCE_CATEGORY_TUTORIAL_STEPS,
+	Name:     "",
+}: "TutorialStep", {
+	Category: model.PREFERENCE_CATEGORY_NOTIFICATIONS,
+	Name:     model.PREFERENCE_NAME_EMAIL_INTERVAL,
+}: "EmailInterval",
+}
+
 func (a *App) BulkExport(writer io.Writer, file string, pathToEmojiDir string, dirNameToExportEmoji string) *model.AppError {
 	if err := a.ExportVersion(writer); err != nil {
 		return err
@@ -154,7 +189,45 @@ func (a *App) ExportAllUsers(writer io.Writer) *model.AppError {
 				continue
 			}
 
-			userLine := ImportLineFromUser(user)
+			// Gathering here the exportable preferences to pass them on to ImportLineFromUser
+			exportedPrefs := make(map[string]*string)
+			allPrefs, err := a.GetPreferencesForUser(user.Id)
+			if err != nil {
+				return err
+			}
+			for _, pref := range allPrefs {
+				// We need to manage the special cases
+				// Here we manage Tutorial steps
+				if pref.Category == model.PREFERENCE_CATEGORY_TUTORIAL_STEPS {
+					pref.Name = ""
+					// Then the email interval
+				} else if pref.Category == model.PREFERENCE_CATEGORY_NOTIFICATIONS && pref.Name == model.PREFERENCE_NAME_EMAIL_INTERVAL {
+					switch pref.Value {
+					case model.PREFERENCE_EMAIL_INTERVAL_NO_BATCHING_SECONDS:
+						pref.Value = model.PREFERENCE_EMAIL_INTERVAL_IMMEDIATELY
+					case model.PREFERENCE_EMAIL_INTERVAL_FIFTEEN_AS_SECONDS:
+						pref.Value = model.PREFERENCE_EMAIL_INTERVAL_FIFTEEN
+					case model.PREFERENCE_EMAIL_INTERVAL_HOUR_AS_SECONDS:
+						pref.Value = model.PREFERENCE_EMAIL_INTERVAL_HOUR
+					case "0":
+						pref.Value = ""
+					}
+				}
+				id, ok := exportablePreferences[ComparablePreference{
+					Category: pref.Category,
+					Name:     pref.Name,
+				}]
+				if ok {
+					prefPtr := pref.Value
+					if prefPtr != "" {
+						exportedPrefs[id] = &prefPtr
+					} else {
+						exportedPrefs[id] = nil
+					}
+				}
+			}
+
+			userLine := ImportLineFromUser(user, exportedPrefs)
 
 			userLine.User.NotifyProps = a.buildUserNotifyProps(user.NotifyProps)