Uncommitted changes on SPWeb object

Question

In my simple Powershell script, I keep getting an error "Exception calling "ResetRoleInheritance" : There are uncommitted changes on the SPWEb Object, call SPWeb.Update() to commit the cahnges before calling this method."

I am attempting to reset all subsites with inherited permissions in preparation of cleaning up the permissions for our TeamSites. Where should I be placing SPWeb.Update() in the following code?

$spWeb = Get-SPWeb "http://<sitecollection>/<subsite>/"

Echo "Resetting Permission Inheritance for Site: $spWeb"
$spWeb.ResetRoleInheritance()
$spWeb.Update()

foreach($subSite in $spWeb.Webs)
{
  Echo "Resetting Permission Inheritance for SubSite: $subSite"
  $subSite.ResetRoleInheritance()
  $subSite.Update()
  $subSite.Dispose()
}
$spWeb.Dispose()

Answer 1

This works... for some reason. I have no idea why, really. It most definately could be cleaned up i'm sure as well:

$spWeb = Get-SPWeb "http://<site collection>/<subsite>/"

Echo "Resetting Permission Inheritance for Site: $spWeb"


foreach($subSite in $spWeb.Webs)
{
  $subSite.Update()
  Echo "Resetting Permission Inheritance for SubSite: $subSite"
  $subSite.ResetRoleInheritance()
  $subSite.Update()
  $subSite.Dispose()
}
$spWeb.ResetRoleInheritance()
$spWeb.Update()
$spWeb.Dispose()

Answer 2

I was tired of dealing with this issue so I got around it by fetching each SPWeb individually, using a list of urls as a string array. Something like this:

$urls = (Get-SPWeb "http://<site collection>/<subsite>/").webs | select -exp url

(copy and paste urls to/from text file to new powershell session)

# this is now a brand new SPWeb object each time. to be absolutely sure im not causing the afore-mentioned errors
$urls | foreach { $web = get-spweb $_; $web.resetroleinheritance(); $web.dispose() }

Probably not a great solution for automated scripts but it got me over the line.