Import context in on_modified blocks

astrality/module.py

@@ -206,19 +206,27 @@ def modified_commands(self, specified_path: str) -> Tuple[str, ...]:
     def context_section_imports(
         self,
         trigger: str,
+        modified: Optional[str] = None,
     ) -> Tuple[ContextSectionImport, ...]:
         """
         Return what to import into the global application_context.
 
-        Trigger is one of 'on_startup', 'on_event', or 'on_exit'.
+        Trigger is one of 'on_startup', 'on_event', 'on_modified, or 'on_exit'.
         This determines which section of the module is used to get the context
         import specification from.
+
+        If trigger is 'on_modified', you also need to specify which file is
+        modified, in order to get the correct section.
         """
-        assert trigger in ('on_startup', 'on_event', 'on_exit',)
+        import_config: List[Dict[str, str]]
+        if modified:
+            assert trigger == 'on_modified'
+            import_config = self.module_config[trigger][modified]['import_context']
+        else:
+            assert trigger in ('on_startup', 'on_event', 'on_exit',)
+            import_config = self.module_config[trigger]['import_context']
 
         context_section_imports = []
-        import_config = self.module_config[trigger]['import_context']
-
         for context_import in import_config:
             # Insert placeholders
             from_path = self.interpolate_string(context_import['from_path'])
@@ -643,13 +651,28 @@ def on_modified(self, modified: Path) -> None:
         module = watched_file.module
         specified_path = watched_file.specified_path
 
+        # First import context sections in on_modified block
+        for csi in module.context_section_imports(
+            trigger='on_modified',
+            modified=specified_path,
+        ):
+            self.application_context = insert_into(
+                context=self.application_context,
+                section=csi.into_section,
+                from_section=csi.from_section,
+                from_config_file=self.expand_path(csi.from_config_file),
+            )
+
+        # Now compile templates specified in on_modified block
         for compilation in module.module_config['on_modified'][specified_path]['compile']:
             template = self.templates[compilation['template']]
             self.compile_template(
                 source=template.source,
                 target=template.target,
             )
 
+
+        # Lastly, run commands specified in on_modified block
         modified_commands = module.modified_commands(specified_path)
         for command in modified_commands:
             logger.info(f'[module/{module.name}] Running modified command.')

astrality/tests/module/test_module_filewatching.py

@@ -398,3 +398,43 @@ def test_recompile_templates_when_modified_overridden(
     assert touch_target.is_file()
 
     module_manager.exit()
+
+
+def test_importing_context_on_modification(
+    three_watchable_files,
+    default_global_options,
+    _runtime,
+    test_config_directory,
+):
+    """Test that context values are imported in on_modified blocks."""
+    file1, *_ = three_watchable_files
+    mercedes_context = test_config_directory / 'context' / 'mercedes.yaml'
+
+    application_config = {
+        'module/module_name': {
+            'on_modified': {
+                str(file1): {
+                    'import_context': {
+                        'from_path': str(mercedes_context),
+                    },
+                },
+            },
+        },
+        'context/car': {
+            'manufacturer': 'Tesla',
+        },
+    }
+    application_config.update(default_global_options)
+    application_config.update(_runtime)
+
+    module_manager = ModuleManager(application_config)
+    module_manager.finish_tasks()
+
+    # Sanity check before modifying file1
+    assert module_manager.application_context['car']['manufacturer'] == 'Tesla'
+
+    # After modifying file1, Mercedes should have been imported
+    file1.touch()
+    file1.write_text('new content, resulting in importing Mercedes')
+    time.sleep(0.7)
+    assert module_manager.application_context['car']['manufacturer'] == 'Mercedes'