Merge ~gabrielcocenza/juju-lint:bug/1979382 into juju-lint:master

[Gabriel Cocenza]

warning for applications from other model

- added default alpha space binding for applications that are
  present in the bundle, but miss 'bindings' keyword;
- check if both spaces in a endpoint are not from another model
  to add as mismatch;
- warn log for possible multi-model applications that appear on relations.

Closes-Bug: #1979382
Co-authored-by: Vern Hart <email address hidden>

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Eric Chen (eric-chen)]

review: Approve

[Martin Kalcok (martin-kalcok)]

LGTM

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision ca71a604c57b0c9641780b7cfa48d7e3a39d75c0

diff --git a/jujulint/check_spaces.py b/jujulint/check_spaces.py
index 337f9b2..975661d 100644
--- a/jujulint/check_spaces.py
+++ b/jujulint/check_spaces.py
@@ -62,8 +62,8 @@ class SpaceMismatch:
         """Return a relation object, mapping applications to charms."""
         app1, endpoint1 = self.endpoint1.split(":")
         app2, endpoint2 = self.endpoint2.split(":")
-        charm1 = app_to_charm_map[app1]
-        charm2 = app_to_charm_map[app2]
+        charm1 = app_to_charm_map.get(app1, "")
+        charm2 = app_to_charm_map.get(app2, "")
         return Relation(":".join([charm1, endpoint1]), ":".join([charm2, endpoint2]))
 
 
@@ -97,7 +97,7 @@ def find_space_mismatches(parsed_yaml, debug=False):
     for relation in relations_list:
         space1 = get_relation_space(relation.endpoint1, app_spaces)
         space2 = get_relation_space(relation.endpoint2, app_spaces)
-        if space1 != space2:
+        if space1 != space2 and all([space1 != "XModel", space2 != "XModel"]):
             mismatch = SpaceMismatch(
                 relation.endpoint1, space1, relation.endpoint2, space2
             )
@@ -119,13 +119,18 @@ def get_application_spaces(application_list, parsed_yaml):
     """Return a dictionary with app.binding=space mappings."""
     app_spaces = {}
     for app in application_list:
-        bindings = parsed_yaml["applications"][app].get('bindings', {})
+        bindings = parsed_yaml["applications"][app].get("bindings", {})
+        app_spaces.setdefault(app, {})
         if not bindings:
+            # this probably means that is a single space binding. See LP#1949883
             LOGGER.warning("Application %s is missing explicit bindings", app)
+            LOGGER.warning("Setting default binding of '%s' to alpha", app)
+            app_spaces[app][""] = "alpha"
             continue
         if not bindings.get(""):
-            LOGGER.warning("Application %s does not define explicit default binding", app)
-        app_spaces[app] = {}
+            LOGGER.warning(
+                "Application %s does not define explicit default binding", app
+            )
         for name, value in bindings.items():
             app_spaces[app][name] = value
     return app_spaces
@@ -149,4 +154,8 @@ def get_relation_space(endpoint, app_spaces):
         else:
             return app_spaces[app][service]
     else:
+        LOGGER.warning(
+            "Multi-model is not supported yet. Please check if '%s' is from another model",
+            app,
+        )
         return "XModel"
diff --git a/jujulint/lint.py b/jujulint/lint.py
index 748fc8a..e4afa10 100755
--- a/jujulint/lint.py
+++ b/jujulint/lint.py
@@ -1121,7 +1121,8 @@ class Linter:
                     self._log_with_header(
                         "Relations detected but explicit bindings not found; "
                         "Not specifying explicit bindings may cause problems on models"
-                        " with multiple network spaces.", level=logging.WARNING
+                        " with multiple network spaces.",
+                        level=logging.WARNING,
                     )
             else:
                 self._log_with_header(
diff --git a/tests/test_jujulint.py b/tests/test_jujulint.py
index 11cc514..9155ff9 100644
--- a/tests/test_jujulint.py
+++ b/tests/test_jujulint.py
@@ -824,7 +824,7 @@ applications:
         assert mock_log.call_count == 0
 
     def test_check_spaces_missing_explicit_bindings(self, linter, mocker):
-        """Test that check_spaces shows warning if some application are missing bindings
+        """Test that check_spaces shows warning if some application are missing bindings.
 
         This warning should be triggerred if some applications have bindings and some
         dont.
@@ -847,12 +847,13 @@ applications:
             ],
         }
 
-        expected_warning = "Application %s is missing explicit bindings"
+        expected_warning_callings = [
+            mock.call("Application %s is missing explicit bindings", "prometheus-app"),
+            mock.call("Setting default binding of '%s' to alpha", "prometheus-app"),
+        ]
 
         linter.check_spaces(bundle)
-
-        logger_mock.warning.assert_called_once_with(expected_warning,
-                                                    app_without_binding)
+        assert logger_mock.warning.call_args_list == expected_warning_callings
 
     def test_check_spaces_missing_default_endpoint_binding(self, linter, mocker):
         """Raise warning if application is missing explicit default binding.
@@ -888,5 +889,35 @@ applications:
 
         linter.check_spaces(bundle)
 
-        logger_mock.warning.assert_called_once_with(expected_warning,
-                                                    app_without_default_space)
+        logger_mock.warning.assert_called_once_with(
+            expected_warning, app_without_default_space
+        )
+
+    def test_check_spaces_multi_model_warning(self, linter, mocker):
+        """Test that check_spaces shows warning if some application are from another model."""
+        logger_mock = mocker.patch.object(check_spaces, "LOGGER")
+
+        app_another_model = "prometheus-app"
+        bundle = {
+            "applications": {
+                "telegraf-app": {
+                    "bindings": {
+                        "": "alpha",
+                        "prometheus-client": "alpha",
+                    },
+                },
+            },
+            "relations": [
+                ["telegraf-app:prometheus-client", "prometheus-app:target"],
+            ],
+        }
+
+        expected_warning_callings = [
+            mock.call(
+                "Multi-model is not supported yet. Please check if '%s' is from another model",
+                app_another_model,
+            ),
+        ]
+
+        linter.check_spaces(bundle)
+        assert logger_mock.warning.call_args_list == expected_warning_callings