feat: support focused dev reload scopes

tests/test_devserver.py

@@ -6,11 +6,92 @@ import sys
 import tempfile
 import unittest
 from pathlib import Path
+from types import SimpleNamespace
+from unittest.mock import patch
 
-from govoplan_core.devserver import redacted_database_url
+from govoplan_core.devserver import build_reload_dirs, redacted_database_url
 
 
 class DevserverSmokeTests(unittest.TestCase):
+    def test_reload_dirs_can_be_limited_to_selected_modules(self) -> None:
+        with tempfile.TemporaryDirectory(prefix="govoplan-reload-") as directory:
+            root = Path(directory)
+            core_root = root / "core"
+            calendar_root = root / "calendar"
+            mail_root = root / "mail"
+            extra_root = root / "extra"
+            for path in (core_root, calendar_root, mail_root, extra_root):
+                path.mkdir()
+
+            manifests = (
+                SimpleNamespace(id="calendar"),
+                SimpleNamespace(id="mail"),
+            )
+            config = SimpleNamespace(enabled_modules=(), manifest_factories=())
+            registry = SimpleNamespace(manifests=lambda: manifests)
+
+            def manifest_roots(manifest: object) -> tuple[Path, ...]:
+                return (
+                    calendar_root
+                    if getattr(manifest, "id") == "calendar"
+                    else mail_root,
+                )
+
+            with (
+                patch(
+                    "govoplan_core.devserver._config_source_roots",
+                    return_value=(core_root,),
+                ),
+                patch(
+                    "govoplan_core.devserver._entry_point_source_roots",
+                    return_value=(),
+                ),
+                patch(
+                    "govoplan_core.devserver._manifest_source_roots",
+                    side_effect=manifest_roots,
+                ),
+            ):
+                broad = build_reload_dirs(config, registry=registry)
+                focused = build_reload_dirs(
+                    config,
+                    registry=registry,
+                    module_ids=("calendar",),
+                    extra_dirs=(str(extra_root),),
+                )
+                core_only = build_reload_dirs(
+                    config,
+                    registry=registry,
+                    module_ids=(),
+                )
+
+            self.assertEqual(
+                {str(core_root), str(calendar_root), str(mail_root)},
+                set(broad),
+            )
+            self.assertEqual(
+                {str(core_root), str(calendar_root), str(extra_root)},
+                set(focused),
+            )
+            self.assertEqual([str(core_root)], core_only)
+
+    def test_reload_dirs_reject_disabled_module_selector(self) -> None:
+        config = SimpleNamespace(enabled_modules=(), manifest_factories=())
+        registry = SimpleNamespace(
+            manifests=lambda: (SimpleNamespace(id="calendar"),)
+        )
+        with (
+            patch(
+                "govoplan_core.devserver._config_source_roots",
+                return_value=(),
+            ),
+            self.assertRaisesRegex(SystemExit, "mail"),
+        ):
+            build_reload_dirs(
+                config,
+                registry=registry,
+                module_ids=("mail",),
+            )
+
     def test_database_url_redaction_hides_passwords(self) -> None:
         rendered = redacted_database_url(
             "postgresql+psycopg://govoplan:database-secret@db.example.test/govoplan"