@title Spaces User Guide
@group userguide

Guide to the Spaces application.

Overview
========

The Spaces application makes it easier to manage large groups of objects which
share the same access policy. For example:

  - An organization might make a space for a project in order to satisfy a
    contractual obligation to limit access, even internally.
  - An open source organization might make a space for work related to
    internal governance, to separate private and public discussions.
  - A contracting company might make spaces for clients, to separate them from
    one another.
  - A company might create a spaces for consultants, to give them limited
    access to only the resources they need to do their work.
  - An ambitious manager might create a space to hide her team's work from her
    enemies at the company, that she might use the element of surprise to later
    expand her domain.

Phabricator's access control policies are generally powerful enough to handle
these use cases on their own, but applying the same policy to a large group
of objects requires a lot of effort and is error-prone.

Spaces build on top of policies and make it easier and more reliable to
configure, review, and manage groups of objects with similar policies.


Creating Spaces
=================

Spaces are optional, and are inactive by default. You don't need to configure
them if you don't plan to use them. You can always set them up later.

To activate Spaces, you need to create at least two spaces. Create spaces from
the web UI, by navigating to {nav Spaces > Create Space}. By default, only
administrators can create new spaces, but you can configure this in the
{nav Applications} application.

The first space you create will be a special "default" space, and all existing
objects will be shifted into this space as soon as you create it. Spaces you
create later will be normal spaces, and begin with no objects inside them.

Create the first space (you may want to name it something like "Default" or
"Global" or "Public", depending on the nature of your organization), then
create a second space. Usually, the second space will be something like
"Secret Plans" and have a more restrictive "Visible To" policy.


Using Spaces
============

Once you've created at least two spaces, you can begin using them.

Application UIs will change for users who can see at least two spaces, opening
up new controls which let them work with spaces. They will now be able to
choose which space to create new objects into, be able to move objects between
spaces, and be able to search for objects in a specific space or set of spaces.

In list and detail views, objects will show which space they're in if they're
in a non-default space.

Users with access to only one space won't see these controls, even if many
spaces exist. This simplifies the UI for users with limited access.


Space Policies
==============

Briefly, spacess affect policies like this:

  - Spaces apply their view policy to all objects inside the space.
  - Space policies are absolute, and stronger than all other policies. A
    user who can not see a space can **never** see objects inside the space.
  - Normal policies are still checked: spaces can only reduce access.

When you create a space, you choose a view policy for that space by using the
**Visible To** control. This policy controls both who can see the space, and
who can see objects inside the space.

Spaces apply their view policy to all objects inside the space: if you can't
see a space, you can never see objects inside it. This policy check is absolute
and stronger than all other policy rules, including policy exceptions.

For example, a user can never see a task in a space they can't see, even if
they are an admin and the author and owner of the task, and subscribed to the
task and the view and edit policies are set to "All Users", and they created
the space originally and the moon is full and they are pure of heart and
possessed of the noblest purpose. Spaces are impenetrable.

Even if a user satisfies the view policy for a space, they must still pass the
view policy on the object: the space check is a new check in addition to any
check on the object, and can only limit access.

The edit policy for a space only affects the space itself, and is not applied
to objects inside the space.


Archiving Spaces
================

If you no longer need a space, you can archive it by choosing
{nav Archive Space} from the detail view. This hides the space and all the
objects in it without deleting any data.

New objects can't be created into archived spaces, and existing objects can't
be shifted into archived spaces. The UI won't give you options to choose
these spaces when creating or editing objects.

Additionally, objects (like tasks) in archived spaces won't be shown in most
search result lists by default. If you need to find objects in an archived
space, use the `Spaces` constraint to specifically search for objects in that
space.

You can reactivate a space later by choosing {nav Activate Space}.


Application Email
=================

After activating spaces, you can choose a space when configuring inbound email
addresses in {nav Applications}.

Spaces affect policies for application email just like they do for other
objects: to see or use the address, you must be able to see the space which
contains it.

Objects created from inbound email will be created in the space the email is
associated with.


Limitations and Caveats
=======================

Some information is shared between spaces, so they do not completely isolate
users from other activity on the install. This section discusses limitations
of the isolation model. Most of these limitations are intrinsic to the policy
model Phabricator uses.

**Shared IDs**: Spaces do not have unique object IDs: there is only one `T1`,
not a separate one in each space. It can be moved between spaces, but `T1`
always refers to the same object. In most cases, this makes working with
spaces simpler and easier.

However, because IDs are shared, users in any space can look at object IDs to
determine how many objects exist in other spaces, even if they can't see those
objects. If a user creates a new task and sees that it is `T5000`, they can
know that there are 4,999 other tasks they don't have permission to see.

**Globally Unique Values**: Some values (like usernames, email addresses,
project hashtags, repository callsigns, and application emails) must be
globally unique.

As with normal policies, users may be able to determine that a `#yolo` project
exists, even if they can't see it: they can try to create a project using the
`#yolo` hashtag, and will receive an error if it is a duplicate.

**User Accounts**: Spaces do not apply to users, and can not hide the existence
of user accounts.

For example, if you are a contracting company and have Coke and Pepsi as
clients, the CEO of Coke and the CEO of Pepsi will each be able to see that the
other has an account on the install, even if all the work you are doing for
them is separated into "Coke" and "Pepsi" spaces.
