I have a usecase wherein a Partner user creates a Case which gets assigned to internal Salesforce user. The agent resolves the case and wanted to collaborate with the partner user with @mention tags but unfortunately, its not coming up. Is this a bug or work as designed .
However, the inverse works, from a partner community chatter feed I am able to @mention salesforce internal user.
Any inputs are welcome
Thanks
JJ
I'd say it's not possible to do this the way you described it. After moving to communities your partners will have access to Chatter but it will be independant from internal organization's Chatter (let's call it Internal Community). Profiles, Groups, Files and all activity everything is visible only inside a community even if you're a member of all communities.
This screen is taken from this documentation page: http://help.salesforce.com/apex/HTViewHelpDoc?id=networks_visibility.htm
So to achieve what you would like to have you would need to add some internal users to partner community. Then creating such private group shouldn't be a problem.
The only way to @mention someone in apex is using the ConnectApi (AKA Chatter in apex) and not by just creating a FeedItem in apex. You'll need to refactor most everything in your code around the posting to Chatter. Here is a code sample of a text post with a mention borrowed from an example that Jeff Douglas has on his blog:
// makes a simple chatter text post to the specified user from the running user
public static void mentionTextPost(Id userId, Id userToMentionId, String postText) {
ConnectApi.MessageBodyInput messageInput = new ConnectApi.MessageBodyInput();
messageInput.messageSegments = new List();
// add some text before the mention
ConnectApi.TextSegmentInput textSegment = new ConnectApi.TextSegmentInput();
textSegment.text = 'Hey ';
messageInput.messageSegments.add(textSegment);
// add the mention
ConnectApi.MentionSegmentInput mentionSegment = new ConnectApi.MentionSegmentInput();
mentionSegment.id = userToMentionId;
messageInput.messageSegments.add(mentionSegment);
// add the text that was passed
textSegment = new ConnectApi.TextSegmentInput();
textSegment.text = postText;
messageInput.messageSegments.add(textSegment);
ConnectApi.FeedItemInput input = new ConnectApi.FeedItemInput();
input.body = messageInput;
// post it
ConnectApi.ChatterFeeds.postFeedItem(null, ConnectApi.FeedType.UserProfile, userId, input, null);
}
Lastly, it's worth noting that you can only post as the running user. It's not possible to post on anyone else's behalf.
Best Answer
Two things must happen in order to @mention a community user on a record feed. The record must be viewed and the Chatter post initiated by the internal user in the communities context. In other words, you must be viewing the record with the Community base URL( e.g. https://mycommunity.force.com/recordid ). Second, the visibility of the Chatter post from the internal user must be set to Everyone. The default is internal users.
EDIT: To add, this is not a bug, this is by design. Communities users are not part of your internal Salesforce CRM. Although records can span communities and your "internal" community, Chatter on those records is contextual to the place you are posting it.