Update aquery documentation (Known Issues)
This is to include the case of Shared Action.
RELNOTES: None
@@ -383,11 +383,23 @@ $ bazel aquery 'inputs(".*cpp", deps(//src/target_a))'
<h2 id='known-issues'>Known Issues</h2>
+<h3 id='shared-actions'>Handling Shared Actions</h3>
+
+<p>
+ Sometimes actions are
+ <a href="https://source.bazel.build/bazel/+/master:src/main/java/com/google/devtools/build/lib/actions/Actions.java;l=59;drc=146d51aa1ec9dcb721a7483479ef0b1ac21d39f1">shared</a>
+ between configured targets.
+
+ In the execution phase, those shared actions are
+ <a href="https://source.bazel.build/bazel/+/master:src/main/java/com/google/devtools/build/lib/actions/Actions.java;l=241;drc=003b8734036a07b496012730964ac220f486b61f">simply considered as one</a> and only executed once.
+ However, aquery operates on the pre-execution, post-analysis action graph, and hence treats these
+ like separate actions whose output Artifacts have the exact same <code>execPath</code>. As a result,
+ we'll have equivalent Artifacts appearing duplicated.
+</p>
<p>
The list of aquery issues/planned features can be found on
<a href="https://github.com/bazelbuild/bazel/labels/team-Performance">GitHub</a>.
</p>
-
<h2 id='updates'>Updates</h2>
<p>
