keep CLI units current during rebuilds

scripts/test_dependency_invalidation.sh

@@ -84,14 +84,24 @@ rebuild_lock_pid=$!
 sleep 0.2
 sed -i 's/dependency-marker-b/dependency-marker-d/' "$source_dir/child.uce"
 started_at=$(date +%s%N)
-assert_marker parent dependency-marker-b
+http_during_lock=$(http_marker)
 elapsed_ms=$(( ($(date +%s%N) - started_at) / 1000000 ))
+if [[ "$http_during_lock" != *"dependency-marker-b"* ]]; then
+	echo "HTTP request did not serve the last complete artifact during rebuild: $http_during_lock" >&2
+	exit 1
+fi
 if (( elapsed_ms >= 2000 )); then
-	echo "request waited ${elapsed_ms}ms for an active transitive rebuild" >&2
+	echo "HTTP request waited ${elapsed_ms}ms for an active transitive rebuild" >&2
+	exit 1
+fi
+started_at=$(date +%s%N)
+assert_marker parent dependency-marker-d
+elapsed_ms=$(( ($(date +%s%N) - started_at) / 1000000 ))
+if (( elapsed_ms < 2000 )); then
+	echo "CLI request returned before the locked rebuild published the current artifact (${elapsed_ms}ms)" >&2
 	exit 1
 fi
 wait "$rebuild_lock_pid"
-assert_marker parent dependency-marker-d
 
 # Warm every configured worker, then replace the artifact while retaining its
 # whole-second mtime. The worker cache must notice the nanosecond/ctime change.