[FIX] core: using absolute paths

Start odoo-bin using a tier module (like `python3 -m pdb odoo-bin`), the
odoo/addons __path__ contains the relative link to the modules instead
of the absolute link like when directly started (`python3 odoo-bin`).

This cause trouble importing modules because it reuses the relative path
from within other directories.

closes odoo/odoo#39164

Signed-off-by: Xavier Dollé (xdo) <xdo@odoo.com>

odoo/__init__.py

@@ -8,7 +8,12 @@
 # odoo must be a namespace package for odoo.addons to become one too
 # https://packaging.python.org/guides/packaging-namespace-packages/
 #----------------------------------------------------------
-__path__ = __import__('pkgutil').extend_path(__path__, __name__)
+import pkgutil
+import os.path
+__path__ = [
+    os.path.abspath(path)
+    for path in pkgutil.extend_path(__path__, __name__)
+]
 
 import sys
 assert sys.version_info > (3, 6), "Outdated python version detected, Odoo requires Python >= 3.6 to run."

odoo/addons/__init__.py

@@ -17,4 +17,9 @@ Importing them from here is deprecated.
 # make odoo.addons a namespace package, while keeping this __init__.py
 # present, for python 2 compatibility
 # https://packaging.python.org/guides/packaging-namespace-packages/
-__path__ = __import__('pkgutil').extend_path(__path__, __name__)
+import pkgutil
+import os.path
+__path__ = [
+    os.path.abspath(path)
+    for path in pkgutil.extend_path(__path__, __name__)
+]