From 5bbc50faa49114cc6c4e0ae2b4b93351c33b6bbd Mon Sep 17 00:00:00 2001
From: Martin Kalcok <69471063+mkalcok@users.noreply.github.com>
Date: Tue, 25 Apr 2023 12:18:58 +0200
Subject: [PATCH] Backport ErrorStatus to 1.5 branch (#875) (#927)

Add ErrorStatus so that getting Unit/App.status when the status is
"error" does not raise.

Co-authored-by: PietroPasotti <starfire.daemon@gmail.com>
Co-authored-by: Ben Hoyt <ben.hoyt@canonical.com>
---
 ops/model.py       | 10 ++++++++++
 test/test_model.py | 47 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/ops/model.py b/ops/model.py
index 9412ae989..6ade16cc7 100644
--- a/ops/model.py
+++ b/ops/model.py
@@ -1158,6 +1158,16 @@ def __repr__(self):
         return "UnknownStatus()"
 
 
+@StatusBase.register
+class ErrorStatus(StatusBase):
+    """The unit status is error.
+
+    The unit-agent has encountered an error (the application or unit requires
+    human intervention in order to operate correctly).
+    """
+    name = 'error'
+
+
 @StatusBase.register
 class ActiveStatus(StatusBase):
     """The unit is ready.
diff --git a/test/test_model.py b/test/test_model.py
index 173168fa6..9e45b28ff 100755
--- a/test/test_model.py
+++ b/test/test_model.py
@@ -2283,7 +2283,7 @@ def test_status_is_app_forced_kwargs(self):
                 case()
 
     def test_local_set_invalid_status(self):
-        # juju return exit code 1 if you ask to set status to 'unknown'
+        # juju returns exit code 1 if you ask to set status to 'unknown' or 'error'
         meta = ops.charm.CharmMeta.from_yaml('''
             name: myapp
         ''')
@@ -2293,20 +2293,65 @@ def test_local_set_invalid_status(self):
 
         with self.assertRaises(ops.model.ModelError):
             model.unit.status = ops.model.UnknownStatus()
+        with self.assertRaises(ops.model.ModelError):
+            model.unit.status = ops.model.ErrorStatus()
 
         self.assertEqual(fake_script_calls(self, True), [
             ['status-set', '--application=False', 'unknown', ''],
+            ['status-set', '--application=False', 'error', ''],
         ])
 
         with self.assertRaises(ops.model.ModelError):
             model.app.status = ops.model.UnknownStatus()
+        with self.assertRaises(ops.model.ModelError):
+            model.app.status = ops.model.ErrorStatus()
 
         # A leadership check is needed for application status.
         self.assertEqual(fake_script_calls(self, True), [
             ['is-leader', '--format=json'],
             ['status-set', '--application=True', 'unknown', ''],
+            ['status-set', '--application=True', 'error', ''],
         ])
 
+    def test_local_get_status(self):
+        for name, expected_cls in (
+            ("active", ops.model.ActiveStatus),
+            ("waiting", ops.model.WaitingStatus),
+            ("blocked", ops.model.BlockedStatus),
+            ("maintenance", ops.model.MaintenanceStatus),
+            ("error", ops.model.ErrorStatus),
+        ):
+            meta = ops.charm.CharmMeta.from_yaml('''
+                name: myapp
+            ''')
+            model = ops.model.Model(meta, self.backend)
+
+            with self.subTest(name):
+                content = json.dumps({
+                    "message": "foo",
+                    "status": name,
+                    "status-data": {},
+                })
+                fake_script(self, 'status-get', "echo '{}'".format(content))
+
+                self.assertIsInstance(model.unit.status, expected_cls)
+                self.assertEqual(model.unit.status.name, name)
+                self.assertEqual(model.unit.status.message, "foo")
+
+                content = json.dumps({
+                    "application-status": {
+                        "message": "bar",
+                        "status": name,
+                        "status-data": {},
+                    }
+                })
+                fake_script(self, 'status-get', "echo '{}'".format(content))
+                fake_script(self, 'is-leader', 'echo true')
+
+                self.assertIsInstance(model.app.status, expected_cls)
+                self.assertEqual(model.app.status.name, name)
+                self.assertEqual(model.app.status.message, "bar")
+
     def test_status_set_is_app_not_bool_raises(self):
         for is_app_v in [None, 1, 2.0, 'a', b'beef', object]:
             with self.assertRaises(TypeError):