[FIX] Propagate all *_cls/*_class plugin metadata fields in PluginManager

unstract/core/src/unstract/core/plugins/plugin_manager.py

@@ -11,6 +11,11 @@
 from pathlib import Path
 from typing import Any
 
+# Metadata keys ending in either suffix are treated as class/entrypoint handles
+# and promoted onto the registered plugin dict (e.g. entrypoint_cls,
+# exception_cls, service_class).
+_CLASS_HANDLE_SUFFIXES = ("_cls", "_class")
+
 
 class PluginManager:
     """Generic plugin manager for loading and managing application plugins.
@@ -215,13 +220,16 @@ def load_plugins(self) -> None:
                     "metadata": metadata,
                 }
 
-                # Add optional fields if present
-                if "entrypoint_cls" in metadata:
-                    plugin_data["entrypoint_cls"] = metadata["entrypoint_cls"]
-                if "exception_cls" in metadata:
-                    plugin_data["exception_cls"] = metadata["exception_cls"]
-                if "service_class" in metadata:
-                    plugin_data["service_class"] = metadata["service_class"]
+                # Add optional class/entrypoint fields if present, so new plugin
+                # metadata fields don't need this loader updated every time.
+                for key, value in metadata.items():
+                    if not isinstance(key, str):
+                        continue
+                    # `key not in plugin_data` is defensive: none of the fixed
+                    # keys above (version/module/metadata) end in a class-handle
+                    # suffix, so this never actually excludes anything today.
+                    if key.endswith(_CLASS_HANDLE_SUFFIXES) and key not in plugin_data:
+                        plugin_data[key] = value
 
                 self.plugins[plugin_name] = plugin_data
 

unstract/core/tests/test_plugin_manager.py

@@ -0,0 +1,123 @@
+import importlib
+import sys
+
+import pytest
+from unstract.core.plugins.plugin_manager import PluginManager
+
+
+def _write_plugin(plugins_pkg_dir, plugin_name, metadata_body):
+    plugin_dir = plugins_pkg_dir / plugin_name
+    plugin_dir.mkdir()
+    (plugin_dir / "__init__.py").write_text(f"metadata = {metadata_body}\n")
+
+
+@pytest.fixture
+def plugins_pkg_dir(tmp_path, monkeypatch):
+    """Create an importable package directory to hold fake plugins."""
+    pkg_dir = tmp_path / "fake_plugins_pkg"
+    pkg_dir.mkdir()
+    (pkg_dir / "__init__.py").write_text("")
+
+    monkeypatch.syspath_prepend(str(tmp_path))
+    importlib.invalidate_caches()
+
+    yield pkg_dir
+
+    sys.modules.pop("fake_plugins_pkg", None)
+    for name in list(sys.modules):
+        if name.startswith("fake_plugins_pkg."):
+            sys.modules.pop(name)
+
+
+def _load(plugins_pkg_dir):
+    manager = PluginManager(
+        plugins_dir=plugins_pkg_dir,
+        plugins_pkg="fake_plugins_pkg",
+        use_singleton=False,
+    )
+    manager.load_plugins()
+    return manager
+
+
+def test_known_and_unknown_class_fields_are_both_registered(plugins_pkg_dir):
+    """A plugin's *_class/*_cls metadata fields should surface on the plugin dict,
+    including fields the loader has never seen before (e.g. headers_cache_class) -
+    not just the historically hardcoded entrypoint_cls/exception_cls/service_class.
+    """
+    _write_plugin(
+        plugins_pkg_dir,
+        "sample_plugin",
+        '{"name": "sample_plugin", "service_class": str, "headers_cache_class": dict, }',
+    )
+
+    plugin = _load(plugins_pkg_dir).get_plugin("sample_plugin")
+
+    assert plugin["service_class"] is str
+    assert plugin["headers_cache_class"] is dict
+    assert plugin["metadata"]["name"] == "sample_plugin"
+
+
+def test_entrypoint_and_exception_cls_still_supported(plugins_pkg_dir):
+    _write_plugin(
+        plugins_pkg_dir,
+        "sample_plugin",
+        '{"name": "sample_plugin", "entrypoint_cls": int, "exception_cls": ValueError, }',
+    )
+
+    plugin = _load(plugins_pkg_dir).get_plugin("sample_plugin")
+
+    assert plugin["entrypoint_cls"] is int
+    assert plugin["exception_cls"] is ValueError
+
+
+def test_non_class_metadata_fields_are_not_duplicated_at_top_level(plugins_pkg_dir):
+    _write_plugin(
+        plugins_pkg_dir,
+        "sample_plugin",
+        '{"name": "sample_plugin", "description": "just a description", }',
+    )
+
+    plugin = _load(plugins_pkg_dir).get_plugin("sample_plugin")
+
+    assert "description" not in plugin
+    assert plugin["metadata"]["description"] == "just a description"
+
+
+def test_disabled_plugin_is_not_loaded(plugins_pkg_dir):
+    _write_plugin(
+        plugins_pkg_dir,
+        "sample_plugin",
+        '{"name": "sample_plugin", "disable": True}',
+    )
+
+    manager = _load(plugins_pkg_dir)
+
+    assert not manager.has_plugin("sample_plugin")
+
+
+def test_inactive_plugin_is_not_loaded(plugins_pkg_dir):
+    _write_plugin(
+        plugins_pkg_dir,
+        "sample_plugin",
+        '{"name": "sample_plugin", "is_active": False}',
+    )
+
+    manager = _load(plugins_pkg_dir)
+
+    assert not manager.has_plugin("sample_plugin")
+
+
+def test_class_field_propagates_regardless_of_value(plugins_pkg_dir):
+    """A *_class/*_cls field is propagated by name, not filtered by its value -
+    a plugin can legitimately set one to None before it's populated at runtime.
+    """
+    _write_plugin(
+        plugins_pkg_dir,
+        "sample_plugin",
+        '{"name": "sample_plugin", "headers_cache_class": None}',
+    )
+
+    plugin = _load(plugins_pkg_dir).get_plugin("sample_plugin")
+
+    assert "headers_cache_class" in plugin
+    assert plugin["headers_cache_class"] is None