MM-55208 allow search prefixes (#28146)

* Ignore at and tilde for username and channel searches.

* allow using tilde in search suggestions

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/post.go

@@ -1467,9 +1467,11 @@ func (a *App) deletePostFiles(c request.CTX, postID string) {
 }
 
 func (a *App) parseAndFetchChannelIdByNameFromInFilter(c request.CTX, channelName, userID, teamID string, includeDeleted bool) (*model.Channel, error) {
-	if strings.HasPrefix(channelName, "@") && strings.Contains(channelName, ",") {
+	cleanChannelName := strings.TrimLeft(channelName, "~")
+
+	if strings.HasPrefix(cleanChannelName, "@") && strings.Contains(cleanChannelName, ",") {
 		var userIDs []string
-		users, err := a.GetUsersByUsernames(strings.Split(channelName[1:], ","), false, nil)
+		users, err := a.GetUsersByUsernames(strings.Split(cleanChannelName[1:], ","), false, nil)
 		if err != nil {
 			return nil, err
 		}
@@ -1484,8 +1486,8 @@ func (a *App) parseAndFetchChannelIdByNameFromInFilter(c request.CTX, channelNam
 		return channel, nil
 	}
 
-	if strings.HasPrefix(channelName, "@") && !strings.Contains(channelName, ",") {
-		user, err := a.GetUserByUsername(channelName[1:])
+	if strings.HasPrefix(cleanChannelName, "@") && !strings.Contains(cleanChannelName, ",") {
+		user, err := a.GetUserByUsername(cleanChannelName[1:])
 		if err != nil {
 			return nil, err
 		}
@@ -1496,7 +1498,7 @@ func (a *App) parseAndFetchChannelIdByNameFromInFilter(c request.CTX, channelNam
 		return channel, nil
 	}
 
-	channel, err := a.GetChannelByName(c, channelName, teamID, includeDeleted)
+	channel, err := a.GetChannelByName(c, cleanChannelName, teamID, includeDeleted)
 	if err != nil {
 		return nil, err
 	}
@@ -1556,7 +1558,7 @@ func (a *App) convertChannelNamesToChannelIds(c request.CTX, channels []string,
 
 func (a *App) convertUserNameToUserIds(c request.CTX, usernames []string) []string {
 	for idx, username := range usernames {
-		user, err := a.GetUserByUsername(username)
+		user, err := a.GetUserByUsername(strings.TrimLeft(username, "@"))
 		if err != nil {
 			c.Logger().Warn("error getting user by username", mlog.String("user_name", username), mlog.Err(err))
 			continue

server/channels/app/post_test.go

@@ -1767,6 +1767,48 @@ func TestSearchPostsForUser(t *testing.T) {
 		assert.Equal(t, []string{}, results.Order)
 		es.AssertExpectations(t)
 	})
+
+	t.Run("should return the same results if there is a tilde in the channel name", func(t *testing.T) {
+		th, _ := setup(t, false)
+		defer th.TearDown()
+
+		page := 0
+
+		searchQueryWithPrefix := fmt.Sprintf("in:~%s %s", th.BasicChannel.Name, searchTerm)
+
+		resultsWithPrefix, err := th.App.SearchPostsForUser(th.Context, searchQueryWithPrefix, th.BasicUser.Id, th.BasicTeam.Id, false, false, 0, page, perPage)
+		assert.Nil(t, err)
+		assert.Greater(t, len(resultsWithPrefix.PostList.Posts), 0, "searching using a tilde in front of a channel should return results")
+		searchQueryWithoutPrefix := fmt.Sprintf("in:%s %s", th.BasicChannel.Name, searchTerm)
+
+		resultsWithoutPrefix, err := th.App.SearchPostsForUser(th.Context, searchQueryWithoutPrefix, th.BasicUser.Id, th.BasicTeam.Id, false, false, 0, page, perPage)
+		assert.Nil(t, err)
+		assert.Equal(t, len(resultsWithPrefix.Posts), len(resultsWithoutPrefix.Posts), "searching using a tilde in front of a channel should return the same number of results")
+		for k, v := range resultsWithPrefix.Posts {
+			assert.Equal(t, v, resultsWithoutPrefix.Posts[k], "post at %s was different", k)
+		}
+	})
+
+	t.Run("should return the same results if there is an 'at' in the user", func(t *testing.T) {
+		th, _ := setup(t, false)
+		defer th.TearDown()
+
+		page := 0
+
+		searchQueryWithPrefix := fmt.Sprintf("from:@%s %s", th.BasicUser.Username, searchTerm)
+
+		resultsWithPrefix, err := th.App.SearchPostsForUser(th.Context, searchQueryWithPrefix, th.BasicUser.Id, th.BasicTeam.Id, false, false, 0, page, perPage)
+		assert.Nil(t, err)
+		assert.Greater(t, len(resultsWithPrefix.PostList.Posts), 0, "searching using a 'at' symbol in front of a channel should return results")
+		searchQueryWithoutPrefix := fmt.Sprintf("from:@%s %s", th.BasicUser.Username, searchTerm)
+
+		resultsWithoutPrefix, err := th.App.SearchPostsForUser(th.Context, searchQueryWithoutPrefix, th.BasicUser.Id, th.BasicTeam.Id, false, false, 0, page, perPage)
+		assert.Nil(t, err)
+		assert.Equal(t, len(resultsWithPrefix.Posts), len(resultsWithoutPrefix.Posts), "searching using an 'at' symbol in front of a channel should return the same number of results")
+		for k, v := range resultsWithPrefix.Posts {
+			assert.Equal(t, v, resultsWithoutPrefix.Posts[k], "post at %s was different", k)
+		}
+	})
 }
 
 func TestCountMentionsFromPost(t *testing.T) {

webapp/channels/src/components/suggestion/search_channel_provider.tsx

@@ -49,7 +49,10 @@ export default class SearchChannelProvider extends Provider {
             if (isAtSearch) {
                 channelPrefix = channelPrefix.replace(/^@/, '');
             }
-
+            const isTildeSearch = channelPrefix.startsWith('~');
+            if (isTildeSearch) {
+                channelPrefix = channelPrefix.replace(/^~/, '');
+            }
             this.startNewRequest(channelPrefix);
 
             this.autocompleteChannelsForSearch(