diff --git a/charms/reactive/relations.py b/charms/reactive/relations.py
index f81b23c..969e7af 100644
--- a/charms/reactive/relations.py
+++ b/charms/reactive/relations.py
@@ -14,7 +14,9 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
 
+import os
 import sys
+import importlib
 from inspect import isclass
 
 from charmhelpers.core import hookenv
@@ -25,6 +27,7 @@ from charms.reactive.bus import get_state
 from charms.reactive.bus import set_state
 from charms.reactive.bus import remove_state
 from charms.reactive.bus import StateList
+from charms.reactive.bus import _append_path
 
 
 # arbitrary obj instances to use as defaults instead of None
@@ -200,10 +203,14 @@ class RelationBase(object, metaclass=AutoAccessors):
         """
         # The module has already been discovered and imported.
         module = 'relations.{}.{}'.format(interface, role)
-        if module in sys.modules:
-            return cls._find_subclass(sys.modules[module])
-        else:
-            return None
+        if module not in sys.modules:
+            try:
+                _append_path(hookenv.charm_dir())
+                _append_path(os.path.join(hookenv.charm_dir(), 'hooks'))
+                importlib.import_module(module)
+            except ImportError:
+                return None
+        return cls._find_subclass(sys.modules[module])
 
     @classmethod
     def _find_subclass(cls, module):

0.4.6 breaks charms.openstack (AttributeError: 'NoneType' object has no attribute 'relation_name')
#### Built with charms.reactive 0.4.5: Apr 26 (ok):
https://openstack-ci-reports.ubuntu.com/artifacts/test_charm_pipeline_amulet_full/openstack/charm-tempest/458466/5/16/index.html

#### Built with charms.reactive 0.4.6: Today (fail):
https://openstack-ci-reports.ubuntu.com/artifacts/test_charm_pipeline/openstack/charm-tempest/458466/5/206/index.html

The tempest-0-var-log.tar.bz2  artifact is of interest for both.
diff --git a/tests/test_relations.py b/tests/test_relations.py
index 8f84616..48a664d 100644
--- a/tests/test_relations.py
+++ b/tests/test_relations.py
@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with charm-helpers.  If not, see <http://www.gnu.org/licenses/>.
 
+import os
 import sys
 import mock
 import unittest
@@ -98,8 +99,23 @@ class TestRelationBase(unittest.TestCase):
         self.assertEqual(res.conversations(), ['conv.join'])
 
     @mock.patch.dict('sys.modules')
+    @mock.patch.object(relations.Conversation, 'join')
+    @mock.patch.object(relations, 'hookenv')
+    def test_cold_import(self, hookenv, conv_join):
+        tests_dir = os.path.dirname(__file__)
+        hookenv.charm_dir.return_value = os.path.join(tests_dir, 'data')
+        sys.modules.pop('relations.hyphen-ated.peer', None)
+        hookenv.relation_to_role_and_interface.return_value = ('peer',
+                                                               'hyphen-ated')
+        relations.RelationBase._cache.clear()
+        assert relations.RelationBase.from_name('test') is not None
+
+    @mock.patch.dict('sys.modules')
+    @mock.patch.object(relations, 'hookenv')
     @mock.patch.object(relations.RelationBase, '_find_subclass')
-    def test_find_impl(self, find_subclass):
+    def test_find_impl(self, find_subclass, hookenv):
+        tests_dir = os.path.dirname(__file__)
+        hookenv.charm_dir.return_value = os.path.join(tests_dir, 'data')
         self.assertIsNone(relations.RelationBase._find_impl('role',
                                                             'interface'))
         assert not find_subclass.called

pip install -e .
parse_log_pytest
requirements.txt
coverage mock nose flake8 ipython ipdb pytest
3.6
requirements.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
attrs==22.2.0
backcall==0.2.0
certifi==2021.5.30
charmhelpers==1.2.1
-e git+https://github.com/juju-solutions/charms.reactive.git@59b07bd9447d8a4cb027ea2515089216b8d20549#egg=charms.reactive
coverage==6.2
decorator==5.1.1
flake8==5.0.4
importlib-metadata==4.2.0
importlib-resources==5.4.0
iniconfig==1.1.1
ipdb==0.13.13
ipython==7.16.3
ipython-genutils==0.2.0
jedi==0.17.2
Jinja2==3.0.3
MarkupSafe==2.0.1
mccabe==0.7.0
mock==5.2.0
netaddr==0.10.1
nose==1.3.7
packaging==21.3
parso==0.7.1
pbr==6.1.1
pexpect==4.9.0
pickleshare==0.7.5
pluggy==1.0.0
prompt-toolkit==3.0.36
ptyprocess==0.7.0
py==1.11.0
pyaml==23.5.8
pycodestyle==2.9.1
pyflakes==2.5.0
Pygments==2.14.0
pyparsing==3.1.4
pytest==7.0.1
PyYAML==6.0.1
six==1.17.0
tomli==1.2.3
traitlets==4.3.3
typing_extensions==4.1.1
wcwidth==0.2.13
zipp==3.6.0

name: charms.reactive
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - pip=21.2.2=py36h06a4308_0
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - attrs==22.2.0
      - backcall==0.2.0
      - charmhelpers==1.2.1
      - coverage==6.2
      - decorator==5.1.1
      - flake8==5.0.4
      - importlib-metadata==4.2.0
      - importlib-resources==5.4.0
      - iniconfig==1.1.1
      - ipdb==0.13.13
      - ipython==7.16.3
      - ipython-genutils==0.2.0
      - jedi==0.17.2
      - jinja2==3.0.3
      - markupsafe==2.0.1
      - mccabe==0.7.0
      - mock==5.2.0
      - netaddr==0.10.1
      - nose==1.3.7
      - packaging==21.3
      - parso==0.7.1
      - pbr==6.1.1
      - pexpect==4.9.0
      - pickleshare==0.7.5
      - pluggy==1.0.0
      - prompt-toolkit==3.0.36
      - ptyprocess==0.7.0
      - py==1.11.0
      - pyaml==23.5.8
      - pycodestyle==2.9.1
      - pyflakes==2.5.0
      - pygments==2.14.0
      - pyparsing==3.1.4
      - pytest==7.0.1
      - pyyaml==6.0.1
      - six==1.17.0
      - tomli==1.2.3
      - traitlets==4.3.3
      - typing-extensions==4.1.1
      - wcwidth==0.2.13
      - zipp==3.6.0
prefix: /opt/conda/envs/charms.reactive

tests/test_relations.py::TestRelationBase::test_cold_import
tests/test_relations.py::TestAutoAccessors::test_accessor tests/test_relations.py::TestAutoAccessors::test_accessor_doc tests/test_relations.py::TestRelationBase::test_conversation tests/test_relations.py::TestRelationBase::test_find_impl tests/test_relations.py::TestRelationBase::test_find_subclass tests/test_relations.py::TestRelationBase::test_from_name tests/test_relations.py::TestRelationBase::test_from_state tests/test_relations.py::TestRelationBase::test_get_local tests/test_relations.py::TestRelationBase::test_get_remote tests/test_relations.py::TestRelationBase::test_is_state tests/test_relations.py::TestRelationBase::test_remove_state tests/test_relations.py::TestRelationBase::test_set_local tests/test_relations.py::TestRelationBase::test_set_remote tests/test_relations.py::TestRelationBase::test_set_state tests/test_relations.py::TestRelationBase::test_toggle_state tests/test_relations.py::TestConversation::test_depart tests/test_relations.py::TestConversation::test_get_local tests/test_relations.py::TestConversation::test_get_remote tests/test_relations.py::TestConversation::test_get_remote_departed tests/test_relations.py::TestConversation::test_is_state tests/test_relations.py::TestConversation::test_join tests/test_relations.py::TestConversation::test_key tests/test_relations.py::TestConversation::test_load tests/test_relations.py::TestConversation::test_relation_ids tests/test_relations.py::TestConversation::test_remove_state tests/test_relations.py::TestConversation::test_set_local tests/test_relations.py::TestConversation::test_set_remote tests/test_relations.py::TestConversation::test_set_state tests/test_relations.py::TestConversation::test_toggle_state tests/test_relations.py::TestMigrateConvs::test_migrate tests/test_relations.py::TestRelationCall::test_call_conversations tests/test_relations.py::TestRelationCall::test_call_name tests/test_relations.py::TestRelationCall::test_call_state tests/test_relations.py::TestRelationCall::test_no_impl
charms/reactive/relations.py
charms/reactive/relations.py