Fix unused component detection

There was a bug in unused component detection which was triggered occasionally. It is not entirely clear what triggered it, but it "helped" to have a lot of components.

CHANGES.d/20241118_114301_cz_regression.md

@@ -0,0 +1,3 @@
+- Fix unused component detection
+
+  There was a bug in unused component detection which was triggered occasionally. It is not entirely clear what triggered it, but it "helped" to have a lot of components.

src/batou/__init__.py

@@ -567,9 +567,9 @@ class UnsatisfiedResources(ConfigurationError):
     def from_context(cls, resources):
         self = cls()
         self.unsatisfied_resources = []
-        for key in sorted(resources.keys()):
+        for (key, host), res_for_key in sorted(resources.items()):
             self.unsatisfied_resources.append(
-                (key, [r.name for r in resources[key]])
+                (key, host, [r.name for r in res_for_key])
             )
         return self
 
@@ -578,11 +578,10 @@ def __str__(self):
 
     def report(self):
         output.error("Unsatisfied resource requirements")
-        for key, resources in self.unsatisfied_resources:
+        for key, host, resources in self.unsatisfied_resources:
             output.line(
-                '    Resource "{}" required by {}'.format(
-                    key, ",".join(resources)
-                ),
+                f'    Resource "{key}" at host {host} required by '
+                f'{",".join(resources)}',
                 red=True,
             )
 

src/batou/resources.py

@@ -154,7 +154,7 @@ def unsatisfied(self):
             if not any(s.strict for s in subscribers):
                 continue
             if key not in self.resources:
-                unsatisfied.add(key)
+                unsatisfied.add((key, None))
                 continue
             for s in subscribers:
                 if s.host is None:
@@ -163,25 +163,25 @@ def unsatisfied(self):
                     resource_root.host.name == s.host.name
                     for resource_root in self.resources[key]
                 ):
-                    unsatisfied.add(key)
+                    unsatisfied.add((key, s.host.name))
                     break
         return unsatisfied
 
     @property
     def unsatisfied_components(self):
         components = set()
-        for resource in self.unsatisfied:
+        for resource, host in self.unsatisfied:
             components.update(
-                [s.root for s in self._subscriptions(resource, None)]
+                [s.root for s in self._subscriptions(resource, host)]
             )
         return components
 
     @property
     def unsatisfied_keys_and_components(self):
         keys = {}
-        for resource in self.unsatisfied:
-            keys[resource] = set(
-                [s.root for s in self._subscriptions(resource, None)]
+        for resource, host in self.unsatisfied:
+            keys[(resource, host)] = set(
+                [s.root for s in self._subscriptions(resource, host)]
             )
         return keys
 

src/batou/tests/test_resources.py

@@ -34,4 +34,7 @@ def test_mentions_missing_requirement_with_host_requirement(sample_service):
     assert len(errors) == 2
     assert isinstance(errors[0], UnsatisfiedResources)
     assert isinstance(errors[1], NonConvergingWorkingSet)
-    assert "key" in str(errors[0].__dict__)
+    assert errors[0].unsatisfied_resources == [
+        ("key", "host1", []),
+        ("unrelated", None, ["component1"]),
+    ]