@@ -300,6 +300,13 @@ function _setup_package_with_constraints_edit {

     local flags=$2

     local extras=$3

+    # Normalize the directory name to avoid

+    # "installation from path or url cannot be constrained to a version"

+    # error.

+    # REVISIT(yamamoto): Remove this when fixed in pip.

+    # https://github.com/pypa/pip/pull/3582

+    project_dir=$(cd $project_dir && pwd)

+

     if [ -n "$REQUIREMENTS_DIR" ]; then

         # Constrain this package to this project directory from here on out.

         local name