hello,
We upgrades to 15.0.2 and seems unshare and link sharings are missing
this one?

I have the same issue. And @BurtGummer , yes, this menu is missing.
I had similar issues in 14.xx, but it turned out this was due to some ad-blockers and the like. This time, no browser I tried (Chrome, Firefox, Opera, Edge, IE) with our without private mode or disabled ad-blockers brings the menu back.
Already shared resources stay shared, but cannot be edited any more.
There are no error messages in the log.

Hi, same issue to me -- NC-15.0.2, complete new installation (after upgrade failure).
Not only the menu is missing, the whole "Share link" line inclusive "Copy to clipboard". Tested in five browsers on Linux, also browsers without any Addon. Also tested in IE-11 on Win-7.
The app "File sharing" is enabled and active?
I have the same issue on 15.02 stable. Browser is Firefox 64.

Sharing is enabled (Allow users to share via link). I can still share/unshare folders and files in android mobile app.
Thanks guys for all you hard work.
Same here. The functionality is there, i can still create and edit shares via the apps and the desktop client. On the Web GUI the controls are completely invisible. This was a NEW install of 15.0.1 via the web installer and broke after upgrading to 15.0.2 via online update.
@BurtGummer, yes, "File sharing" v1.7.0 is (and was) already enabled. If I click on an existing share I can't neither disable it nor change some share settings.
Yes, sharing is enabled and active.
is the app socialsharing_email active on your instances?
then it's probably a duplicate of nextcloud/socialsharing#29
I can confirm that disabling "Social sharing via email" app sorted out the issue for me. Thank you!

Indeed, it works again if I disable Social sharing via email.
Only disabling the app "Social sharing via email" doesn't correct this issue, I had to disable the app "Share by mail" too. NOW the share menu appears correctly again. Many thanks for your support! (y)
I had to remove the "Social sharing via email" and the "Social sharing via twitter" apps
The "Share by mail" app is present on both of my 15.0.2 instances with no issue
Same issue on 15.0.2. Disabling e-mail share apps doesn't help.
... and "Social sharing via Diaspora" too!
Yesterday for a short time (half an hour or so; why depending on time?) everything was fine with the Share Button as I described above. Then it was not shown again. After disabling "Social sharing via Diaspora" it appears again. Strange ;-)
Disabling "Social sharing via Diaspora" helped here, too.
It was the only social sharing app enabled in my instance.
should be fixed with nextcloud/server#13738 see https://github.com/nextcloud/socialsharing/issues/29#issuecomment-456421423
Most helpful comment
is the app socialsharing_email active on your instances?
then it's probably a duplicate of nextcloud/socialsharing#29