diff --git a/inc/python b/inc/python
index ca185f0..bba9cda 100644
--- a/inc/python
+++ b/inc/python
@@ -238,7 +238,9 @@
     if [ -n "$REQUIREMENTS_DIR" ]; then
         # Constrain this package to this project directory from here on out.
         local name=$(awk '/^name.*=/ {print $3}' $project_dir/setup.cfg)
-        $REQUIREMENTS_DIR/.venv/bin/edit-constraints $REQUIREMENTS_DIR/upper-constraints.txt -- $name "$flags $project_dir"
+        $REQUIREMENTS_DIR/.venv/bin/edit-constraints \
+            $REQUIREMENTS_DIR/upper-constraints.txt -- $name \
+            "$flags file://$project_dir#egg=$name"
     fi
 
     setup_package $project_dir $flags