How to find if a list/document library has item(s) with unique permissions using PowerShell - SharePoint Online

Question

With SharePoint Online, are there any ways to find if a list/document library has item(s) with unique permissions using PowerShell without iterating through all the items in it.

When a list/library has item(s) with unique permission, the permission page - List(Library) Settings -> Permissions for this list (document library) - shows a message "Some items of this list may have unique permissions which are not controlled from this page."

I am wondering how the page is getting this information - I checked the definition of SPList (https://msdn.microsoft.com/en-us/library/microsoft.sharepoint.client.list_properties.aspx) but there do not seem to have a relevant property for this.

I have a PowerShell script with CSOM to collect various information associated with lists. If iterating through all the items in a list and check their permission, it would slow the script down considerably especially when a list contains a large number of items.

Answer 1

This is possible in PowerShell or SharePoint Server Object Model by using SPList method GetItemsWithUniquePermissions https://msdn.microsoft.com/en-us/library/ee572463.aspx

Examples:-

PowerShell

$web = Get-SPWeb("http://site_url")
$list = $web.Lists["list_title"]
$itemCount = $list.GetItemsWithUniquePermissions().Count

SharePoint Server Object Model

using(SPSite site = new SPSite("http://site_url"))
{
    using(SPWeb web = site.OpenWeb())
    {
        SPList list = web.Lists["list_title"];
        int itemCount = list.GetItemsWithUniquePermissions().Count;
    }
}