[FIX] base: assets cannot load on Windows

Assets can not be loaded on Windows due to the OS path separator
character ´\´.

This commit fixes it.

Specifically:

- `os.path.split` needed to get changed because it only serves to split
  the last part of the path (equivalent to `str.rsplit(os.path.sep, 1)`).
  What we want instead is to replace all `os.path.sep` by `"/"`.

- for a template file, when verifying that the path is safe we were
  trying to determine if it was including the string `{addon}/static/`.
  It should have been converted to the correct OS representation of a
  path. Now it is.

- `_get_paths` method should return the OS-style paths for the template
  files and the web-style path for others.

closes odoo/odoo#69290

X-original-commit: e8e724ad6c754484bc5f03ce3262d2337e476d42
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>
Co-authored-by: Lucas Perais <lpe@odoo.com>
Co-authored-by: François Georis <fge@odoo.com>

odoo/addons/base/models/ir_asset.py

@@ -35,7 +35,9 @@ WILDCARD_CHARACTERS = {'*', "?", "[", "]"}
 
 def fs2web(path):
     """Converts a file system path to a web path"""
-    return '/'.join(os.path.split(path))
+    if os.path.sep == '/':
+        return path
+    return '/'.join(path.split(os.path.sep))
 
 def can_aggregate(url):
     parsed = urls.url_parse(url)
@@ -347,8 +349,10 @@ class IrAsset(models.Model):
                 except (ValueError, FileNotFoundError):
                     return False
                 if path.rpartition('.')[2] in TEMPLATE_EXTENSIONS:
+                    # normpath will strip the trailing /, which is why it has to be added afterwards
+                    static_path = os.path.normpath("%s/static" % addon) + os.path.sep
                     # Forbid xml to leak
-                    return ("%s/static/" % addon) in path
+                    return static_path in path
                 return True
 
             len_paths = len(paths)
@@ -359,7 +363,7 @@ class IrAsset(models.Model):
             # files are read from the file system. But web assets (scripts and
             # stylesheets) must be loaded using relative paths, hence the trimming
             # for non-xml file paths.
-            paths = [path if path.split('.')[-1] in TEMPLATE_EXTENSIONS else path[len(addons_path):] for path in paths]
+            paths = [path if path.split('.')[-1] in TEMPLATE_EXTENSIONS else fs2web(path[len(addons_path):]) for path in paths]
 
         else:
             addon = None