bin/mkosi: support running from the source checkout

It is super useful for development if we can use the helper and not
worry about setting PYTHONPATH manually. We can also run mkosi directly after
cloing the repo, without doing any other setup.

diff --git a/bin/mkosi b/bin/mkosi
index e72ec263ccf53889cf5b49ab867734f6864da2de..721a36cb56bdb2865ba7fbc614359ab2ef7db13d 100755 (executable)
--- a/bin/mkosi
+++ b/bin/mkosi
@@ -9,16 +9,18 @@
 # home directory via "python3 -m pip install --user"
 #
 # We support installation via:
-# sudo python3 -m pip install <mkosi>
-# python3 -m pip install --user <mkosi>
-# python3 -m pip install --user --editable <mkosi>
-# /path/to/venv/bin/python3 -m pip install <mkosi>
+#   sudo python3 -m pip install <mkosi>
+#   python3 -m pip install --user <mkosi>
+#   python3 -m pip install --user --editable <mkosi>
+#   /path/to/venv/bin/python3 -m pip install <mkosi>
+# and running directly from the source checkout.
 #
-# In the first and the last case this script is a noop because we leave it up to
-# the python binary to set up its path, in the case of "--user" installation we
-# prepend PYTHON_PATH with the original users
+# In the first and the next-to-last cases this script is a noop because we leave
+# it up to the python binary to set up its path. In the case of '--user'
+# installation we prepend PYTHON_PATH with the original user's
 # ~/.local/lib/pythonX.Y/site-packages or the directory where mkosi has been
 # cloned to, for "--editable" installations, when this script is run via sudo.
+# When running from a source checkout, we prepend that directory to the path.
 
 PYROOT=$(dirname "$0")
 
@@ -36,7 +38,10 @@ PYVERSION=$($PYTHON --version | cut -d ' ' -f 2 | cut -d '.' -f 1-2)
 
 declare PREPEND_PYTHONPATH
 
-if [[ -n $SUDO_USER ]] && \
+if [[ -e "${PYROOT}/../setup.py" ]]
+then
+    PREPEND_PYTHONPATH="$(dirname ${PYROOT})"
+elif [[ -n $SUDO_USER ]] && \
        [[ -z $VIRTUAL_ENV ]] && \
        [[ "$SYSTEM_PYTHON_OR_VENV" == false ]]
 then