Bug 1598574

For the record, this is the hideous string comparison I came up with, that seems to work:

diff --git a/pyanaconda/dbus/typing.py b/pyanaconda/dbus/typing.py
index ea8a2999c..8915a421f 100644
--- a/pyanaconda/dbus/typing.py
+++ b/pyanaconda/dbus/typing.py
@@ -150,14 +150,15 @@ class DBusType(object):
     def _is_container_type(type_hint):
         """Is it a container type?"""
         # Try to get the "base" type of the container type.
-        origin = getattr(type_hint, "__origin__", None)
-        return origin in DBusType._container_type_mapping
+        return any(str(type_hint).startswith(str(hintcls))
+                   for hintcls in DBusType._container_type_mapping)
 
     @staticmethod
     def _get_container_type(type_hint):
         """Return a container type."""
         # Get the "base" type of the container.
-        origin = type_hint.__origin__
+        origin = [hintcls for hintcls in DBusType._container_type_mapping
+                  if str(type_hint).startswith(str(hintcls))][0]
         # Get the arguments of the container.
         args = type_hint.__args__
 

....ew.

Some interesting discussion here:

https://stackoverflow.com/questions/49171189/whats-the-correct-way-to-check-if-an-object-is-a-typing-generic
https://github.com/python/typing/issues/136

Someone at github suggested using this:

https://github.com/ilevkivskyi/typing_inspect

seems like its `get_origin()` would be what we want, but it's not yet packaged for Fedora.

Well...actually, it looks like that doesn't support List or Dict, so not much use.

$ python3.6
>>> from typing import Tuple
>>> tup = Tuple[int, str]
>>> origin = getattr(tup, "__origin__")
>>> issubclass(origin, tuple)
True


$ python3.7
>>> from typing import Tuple
>>> tup = Tuple[int, str]
>>> origin = getattr(tup, "__origin__")
>>> issubclass(origin, tuple)
True


Would this be helpful?

E.g. instead of:

return origin in DBusType._container_type_mapping

any(issubclass(origin, c) for c in DBusType._container_type_mapping)

note that aslo this is true on both versions:

>>> issubclass(origin, Tuple)
True

And:

     @staticmethod
     def _get_container_type(type_hint):
         """Return a container type."""
         # Get the "base" type of the container.
-        origin = type_hint.__origin__
+        origin = tuple(c for c in DBusType._container_type_mapping if issubclass(type_hint.__origin__, c))[0]
         # Get the arguments of the container.
         args = type_hint.__args__

Sorry, I'm from cell phone data only, on my laptop, outside (it's a public holiday here) so I won't be able to try it out.

It's a bit ugly, but at least it's not string matching.

Note that the tuple comprehension might be replaced with a generator and 1 call to next, if we want to make it more efficient. I have no idea how long the dbus type list is.

any(issubclass(origin, c) for c in DBusType._container_type_mapping)

Might be easier to just:

issubclass(origin, DBusType._container_type_mapping)

Well, DBusType._container_type_mapping must be (converted to) a tuple for that to actually work.

Thanks, Miro - that's the suggestion I like most so far. I've sent a PR based on it:

https://github.com/rhinstaller/anaconda/pull/1526

I'm going to do an anaconda build with that PR patched in, as we really want to try and get a compose with Python 3.7 through some time soon.

Is there anything that could have been done to prevent this kind of breakage? E.g. is it possible to build a "scratch" compose from a side tag to see if it works? If so, we can set it as a goal for next time (Python 3.8).

nirik should know the answer to that, I'm not sure off the top of my head whether that's possible or not.

There isn't currently, but we really want there to be. For just such things as this.

Thanks for the info. 3.8 is couple releases away, so hopefully, it'll be possible by then.


BTW latest compose says DOOMED but there are os many logs that I don't know where to look for the cause to see if it is related to this bug or something else.

It's something else currently. bug 1599009 (cdrkit changes broke k3b that broke the kde spin).

You're most likely to find discussion of failed composes at https://pagure.io/dusty/failed-composes/issues and/or on #fedora-releng on IRC, FWIW.

Note this is fixed for current composes by downstream patch of my PR, but the PR is still open upstream. So leaving the bug open for now.

Fixed in a pull request that is based on a solution from Adam:
https://github.com/rhinstaller/anaconda/pull/1538

The PR is merged and this has been patched in rawhide long ago.