Only show rebuild permission messages to users who can access link

@averagejoe3000 thanks for the work here.

I suppose that we should add a test to ensure that we don't show the message to someone who can edit the settings, but not rebuild the access permissions.

Hi !
IMO the availability of this messages — considering that in my experience, access to these forms is usually granted to users with elevated permissions — could be something configurable within the module itself, WDYT ?

Thank you!

Added test coverage and used ->access($current_user) to check access, instead of a permission check.

Please review.

I think a better approach for both this issue and the underlying original issue #3357181: Does not react to role changes is to just call node_access_needs_rebuild(TRUE) rather than showing a message via content_access_user_update().

1. The current implementation uses addMessage() to show a message to the user, but that only gets displayed once. My reading of #3357181: Does not react to role changes is that this check was added in order to make sure a site owner knows that permissions need to be rebuilt
2. DRY: the node_help() implementation in core already performs multiple checks to decide if the "needs rebuild" message should be shown, including but not limted to checking if the user has the right permission. (NB node_help() currently checks explicitly for the 'administer nodes' permission, although I agree that the checking if $current_user can access the relevant route is better)
3. UX consistency: setting the node access rebuild flag generates a warning message, whereas this module currently sets a status message. (It might be better if this module could check if the role changes actually require a permission rebuild rather than showing a message unconditionally, but as noted in some of the linked issues that feels like a separate and non-trivial issue)

Taking this approach would also mean the test cases added in MR !14 should just check e.g. $this->assertTrue(\Drupal::state()->get('node.node_access_needs_rebuild'), 'Node access permissions need to be rebuilt'); (following NodeAccessRebuildNodeGrantsTest.php in the core node module)

@alt36 I agree, it makes more sense, and this way we're relying on the core behavior without re-inventing the same thing in our module.

Merged in 2.1.x

I'm suggested that we revert the changes introduced in this issue over here:

#3574984-14: 2.1.0-rc2 keeps asking to rebuild permissions

Because these changes call node_access_needs_rebuild(TRUE); a lot of the time when they don't need to.

I'm going to raise a new issue about how to do the content auth grant realm properly, and then that'll mean that we can safely remove the messaging that this ticket was originally about.

Over in #3579507: Re-work the author grant realms I've got a different implementation that doesn't need to recompute the node access records any time a user's roles change.
It should be considered experimental I think, but if anyone wanted to test that out on a dev site and let me know if it works for them that would be much appreciated. I've added tests for the functionality that's changing, but you never know eh?

I'm going to go ahead and mark this issue as 'won't fix' since the proper fix is coming in 3.x / #3579507: Re-work the author grant realms. We're just going to go around in circles trying to do something a bit silly if we try to resolve this message being shown incorrectly etc. The correct way forward is to get the records/grants done right, so that we don't need a message at all, because the system works.

Thanks for your help on this issue everyone, and feel free to pitch in on #3579507: Re-work the author grant realms.