diff --git a/lib/spack/spack/installer.py b/lib/spack/spack/installer.py
index cdfd34fb33e..2e90be882d3 100644
--- a/lib/spack/spack/installer.py
+++ b/lib/spack/spack/installer.py
@@ -1144,6 +1144,7 @@ def priority(self):
 class BuildTask(Task):
     """Class for representing a build task for a package."""
 
+    process_handle: spack.build_environment.ProcessHandle
     started: bool = False
 
     def start(self):