Report root node for unused components, test

src/batou/__init__.py

@@ -453,6 +453,27 @@ def report(self):
             )
 
 
+class UnusedComponentsInitialized(ConfigurationError):
+    """Some components were initialized but never used."""
+
+    sort_key = (5, "unused")
+
+    @classmethod
+    def from_context(cls, components, root):
+        self = cls()
+        self.unused_components = []
+        for component in components:
+            self.unused_components.append(repr(component.__class__.__name__))
+        self.root_name = root.name
+        return self
+
+    def __str__(self):
+        return f"Unused components: {', '.join(self.unused_components)}"
+
+    def report(self):
+        output.error(f"Unused components: {', '.join(self.unused_components)}")
+
+
 class UnsatisfiedResources(ConfigurationError):
     """Some required resources were never provided."""
 

src/batou/environment.py

@@ -28,6 +28,7 @@
     SuperfluousSection,
     UnknownComponentConfigurationError,
     UnsatisfiedResources,
+    UnusedComponentsInitialized,
     UnusedResources,
 )
 from batou._output import output
@@ -497,6 +498,7 @@ def configure(self):
 
             for root in working_set:
                 try:
+                    Component.instances.clear()
                     self.resources.reset_component_resources(root)
                     root.overrides = self.overrides.get(root.name, {})
                     root.prepare()
@@ -516,9 +518,20 @@ def configure(self):
                         )
                     )
                 else:
-                    # configured this component successfully
-                    # we won't have to retry it later
-                    continue
+                    unprepared_components = []
+                    for component in Component.instances:
+                        if not component._prepared:
+                            unprepared_components.append(component)
+                    if unprepared_components:
+                        exceptions.append(
+                            UnusedComponentsInitialized.from_context(
+                                unprepared_components, root
+                            )
+                        )
+                    if not exceptions:
+                        # configured this component successfully
+                        # we won't have to retry it later
+                        continue
                 retry.add(root)
 
             retry.update(self.resources.dirty_dependencies)
@@ -566,17 +579,6 @@ def configure(self):
                 UnusedResources.from_context(self.resources.unused)
             )
 
-        # if any of Component.instances has ._prepared == False, then
-        # warn via output.annotate
-        if not exceptions:
-            for component in Component.instances:
-                if not component._prepared:
-                    output.warn(
-                        "A Component '{}' was initialized but was not prepared (configured).\nThis may not be what you want".format(
-                            component.__class__.__name__
-                        ),
-                    )
-
         for root in order:
             root.log_finish_configure()
 

src/batou/tests/fixture/sample_service/components/hello/component.py

@@ -62,3 +62,12 @@ def configure(self):
 class Sub(Component):
     def configure(self):
         self.log("Sub!")
+
+
+class Unused(Component):
+    pass
+
+
+class BadUnused(Component):
+    def configure(self):
+        Unused()

src/batou/tests/fixture/sample_service/environments/test-unused/environment.cfg

@@ -0,0 +1,5 @@
+[environment]
+connect_method = local
+
+[hosts]
+localhost = badunused

src/batou/tests/test_environment.py

@@ -4,7 +4,7 @@
 
 import batou
 import batou.utils
-from batou.component import Component
+from batou.component import Component, RootComponent
 from batou.environment import Config, Environment
 from batou.host import Host
 
@@ -336,3 +336,11 @@ def test_resolver_overrides_invalid_address(sample_service):
     errors = e.configure()
     assert len(errors) == 1
     assert "thisisinvalid" == errors[0].address
+
+
+def test_unused_components_get_reported(sample_service):
+    e = Environment("test-unused")
+    e.load()
+    errors = e.configure()
+
+    assert any(isinstance(e, batou.UnusedComponentsInitialized) for e in errors)