feat: govern attachment exceptions and ownership transfers

src/govoplan_campaign/backend/routes/sharing.py

@@ -35,7 +35,6 @@ from govoplan_core.security.time import utc_now
 
 from govoplan_campaign.backend.route_support import (
     _access_directory,
-    _clear_current_version_mail_profile_for_owner_transfer,
     _get_campaign_for_principal,
 )
 
@@ -170,59 +169,20 @@ def update_campaign_owner(
     session: Session = Depends(get_session),
     principal: ApiPrincipal = Depends(require_scope("campaigns:campaign:share")),
 ):
-    campaign = _get_campaign_for_principal(session, campaign_id, principal, write=True)
-    if payload.owner_user_id and payload.owner_group_id:
-        raise HTTPException(
-            status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
-            detail="Choose either a user owner or a group owner, not both",
-        )
-    directory = _access_directory()
-    if payload.owner_user_id:
-        owner = directory.get_user(payload.owner_user_id)
-        if owner is not None and (
-            owner.tenant_id != principal.tenant_id or owner.status != "active"
-        ):
-            owner = None
-        if owner is None:
-            raise HTTPException(
-                status_code=status.HTTP_404_NOT_FOUND, detail="Owner user not found"
-            )
-    if payload.owner_group_id:
-        group = directory.get_group(payload.owner_group_id)
-        if group is not None and (
-            group.tenant_id != principal.tenant_id or group.status != "active"
-        ):
-            group = None
-        if group is None:
-            raise HTTPException(
-                status_code=status.HTTP_404_NOT_FOUND, detail="Owner group not found"
-            )
-    owner_changed = (
-        campaign.owner_user_id != payload.owner_user_id
-        or campaign.owner_group_id != payload.owner_group_id
-    )
-    mail_profile_reselection_required = False
-    if owner_changed:
-        mail_profile_reselection_required = (
-            _clear_current_version_mail_profile_for_owner_transfer(session, campaign)
-        )
-
-    campaign.owner_user_id = payload.owner_user_id
-    campaign.owner_group_id = payload.owner_group_id
-    session.add(campaign)
-    audit_from_principal(
+    del payload
+    _get_campaign_for_principal(
         session,
+        campaign_id,
         principal,
-        action="campaign.owner_updated",
-        object_type="campaign",
-        object_id=campaign.id,
-        details={
-            **payload.model_dump(),
-            "mail_profile_reselection_required": mail_profile_reselection_required,
-        },
-        commit=True,
+        write=True,
+    )
+    raise HTTPException(
+        status_code=status.HTTP_409_CONFLICT,
+        detail=(
+            "Direct campaign owner mutation has been retired. Use the "
+            "ownership transfer workflow so the target can accept."
+        ),
     )
-    return CampaignResponse.model_validate(campaign)
 
 
 @router.post(