Document that --output_user_root cannot be used for user sharing any longer.
This hasn't been true since unknown commit (2014), and changing this behavior
would expose us to security issues unless, at least, is fixed.
Fixes
RELNOTES: None.
@@ -2744,19 +2744,13 @@ adb -s deadbeef install ...
<h4 id='flag--output_user_root'><code class='flag'>--output_user_root=<var>dir</var></code></h4>
<p>
- By default, the <code>output_base</code> value is chosen to as to
- avoid conflicts between multiple users building in the same workspace directory.
- In some situations, though, it is desirable to build from a directory
- shared between multiple users; release engineers often do this. In
- those cases it may be useful to deliberately override the default so
- as to ensure "conflicts" (i.e., sharing) between multiple users.
- Use the <code class='flag'>--output_user_root</code> option to achieve this: the
- output base is placed in a subdirectory of the output user root,
- with a unique name based on the workspace, so the result of using an
- output user root that is not a function of <code>$USER</code> is
- sharing. Of course, it is important to ensure (via umask and group
- membership) that all the cooperating users can read/write each
- others files.
+ Points to the root directory where output bases are created unless
+ overriden with <code class='flag'>--output_base</code>. The directory
+ must either not exist or be owned by the calling user. In the past,
+ this was allowed to point to a directory shared among various users
+ but it's not allowed any longer. (We can reconsider allowing this once
+ <a href='https://github.com/bazelbuild/bazel/issues/11100'>#11100</a>
+ is addressed.)
</p>
<p>
If the <code class='flag'>--output_base</code> option is specified, it overrides
