Pass series info into origin for ResolveCharm

Without the series the ResolveCharm will select the latest base for
the charm. E.g. even if we want focal, the ResolveCharm will return
22.04 (jammy) for the base channel in the resulting origin if the
charm supports both jammy and focal.

This communicates the series info with the ResolveCharm via the
inputted origin so the resulting origin will have the correct base
channel.

Fixes #822

Author: cderici

juju/model.py

@@ -552,23 +552,14 @@ async def resolve(self, url, architecture, app_name=None, channel=None, series=N
         origin = client.CharmOrigin(source="charm-hub",
                                     architecture=architecture,
                                     risk=ch.risk,
-                                    track=ch.track)
+                                    track=ch.track,
+                                    series=series)
 
-        charm_url_str, origin, supported_series = await self.charm_resolver(url, origin)
-        charm_url = URL.parse(charm_url_str)
+        charm_url, origin = await self.charm_resolver(url, origin, force)
 
         if app_name is None:
             app_name = url.name
 
-        if series:
-            # Check whether the charm supports this series
-            # or we force it
-            if series in supported_series or force:
-                origin.series = series
-                charm_url.series = series
-            else:
-                raise JujuError("Series {} not supported for {}. Only {}".format(series, url, supported_series))
-
         return DeployTypeResult(
             identifier=str(charm_url),
             app_name=app_name,
@@ -1722,7 +1713,7 @@ async def _add_charm(self, charm_url, origin):
         client_facade = client.ClientFacade.from_connection(self.connection())
         return await client_facade.AddCharm(channel=str(origin.risk), url=charm_url, force=False)
 
-    async def _resolve_charm(self, url, origin):
+    async def _resolve_charm(self, url, origin, force):
         charms_cls = client.CharmsFacade
         if charms_cls.best_facade_version(self.connection()) < 3:
             raise JujuError("resolve charm")
@@ -1733,9 +1724,11 @@ async def _resolve_charm(self, url, origin):
             source = "charm-store"
         else:
             source = "charm-hub"
+
         resp = await charms_facade.ResolveCharms(resolve=[{
             'reference': str(url),
             'charm-origin': {
+                'series': origin.series,
                 'source': source,
                 'architecture': origin.architecture,
                 'track': origin.track,
@@ -1749,7 +1742,18 @@ async def _resolve_charm(self, url, origin):
         if result.error:
             raise JujuError(result.error.message)
 
-        return (result.url, result.charm_origin, result.supported_series)
+        supported_series = result.supported_series
+        charm_url = URL.parse(result.url)
+        if origin.series:
+            # Check whether the charm supports this series
+            # or we force it
+            if origin.series in supported_series or force:
+                result.charm_origin.series = origin.series
+                charm_url.series = origin.series
+            else:
+                raise JujuError("Series {} not supported for {}. Only {}".format(origin.series, result.url, supported_series))
+
+        return charm_url, result.charm_origin
 
     async def _resolve_architecture(self, url):
         if url.architecture: