Gate external auth providers behind SERVER_MODE in desktop mode (#10240)

Desktop mode has no use for the kerberos, ldap, mfa, oauth2 or webserver
authentication providers: AUTHENTICATION_SOURCES defaults to internal, MFA is
inert because mfa_enabled() requires SERVER_MODE, and get_logout_url() already
guards its kerberos and oauth2 branches on SERVER_MODE. So skip importing and
initialising them unless SERVER_MODE is set, leaving desktop mode with
internal authentication alone.

The accompanying test needed wiring into our own runner before it would ever
execute: web/pgadmin/authenticate/tests/ had no __init__.py, so pkgutil did
not report it and find_modules() never reached the module, and the test class
derived from unittest.TestCase rather than BaseTestGenerator, so the
TestsGeneratorRegistry metaclass never registered it and get_suite() could not
pick it up. Both are fixed here, and the two scenarios now run and pass under
regression/runtests.py.

The test no longer asserts that pgadmin.authenticate.mfa is absent from
sys.modules in desktop mode, because it is not: both pgadmin/browser/__init__
and pgadmin/user_login_check import pgadmin.authenticate.mfa.utils
unconditionally. The original assertion only held because the test itself
popped the module first.

web/pgadmin/authenticate/registry.py

@@ -10,6 +10,7 @@
 """External Authentication Registry."""
 
 
+import config
 from pgadmin.utils.dynamic_registry import create_registry_metaclass
 
 
@@ -19,20 +20,21 @@ def load_modules(cls, app=None):
     from . import internal as module
     submodules.append(module)
 
-    from . import kerberos as module
-    submodules.append(module)
+    if config.SERVER_MODE:
+        from . import kerberos as module
+        submodules.append(module)
 
-    from . import ldap as module
-    submodules.append(module)
+        from . import ldap as module
+        submodules.append(module)
 
-    from . import mfa as module
-    submodules.append(module)
+        from . import mfa as module
+        submodules.append(module)
 
-    from . import oauth2 as module
-    submodules.append(module)
+        from . import oauth2 as module
+        submodules.append(module)
 
-    from . import webserver as module
-    submodules.append(module)
+        from . import webserver as module
+        submodules.append(module)
 
     for module in submodules:
         if "init_app" in module.__dict__.keys():

web/pgadmin/authenticate/tests/__init__.py

@@ -0,0 +1,8 @@
+##########################################################################
+#
+# pgAdmin 4 - PostgreSQL Tools
+#
+# Copyright (C) 2013 - 2026, The pgAdmin Development Team
+# This software is released under the PostgreSQL Licence
+#
+##########################################################################

web/pgadmin/authenticate/tests/test_auth_gating.py

@@ -0,0 +1,119 @@
+##########################################################################
+#
+# pgAdmin 4 - PostgreSQL Tools
+#
+# Copyright (C) 2013 - 2026, The pgAdmin Development Team
+# This software is released under the PostgreSQL Licence
+#
+##########################################################################
+
+"""Verify that external authentication providers are only loaded in server
+mode, and that desktop mode is left with internal authentication alone.
+"""
+
+import sys
+
+import config
+from pgadmin.authenticate.registry import AuthSourceRegistry
+from pgadmin.utils.route import BaseTestGenerator
+
+# Providers registered as authentication sources. MFA is deliberately absent:
+# it is loaded by the same registry but registers no auth source of its own.
+EXTERNAL_SOURCES = ['kerberos', 'ldap', 'oauth2', 'webserver']
+
+# Modules whose import can be asserted on. mfa is excluded because
+# pgadmin/browser/__init__.py and pgadmin/user_login_check.py both import
+# pgadmin.authenticate.mfa.utils unconditionally, so the mfa package is
+# present in sys.modules in desktop mode whatever this registry does.
+EXTERNAL_MODULES = [
+    'pgadmin.authenticate.{0}'.format(name) for name in EXTERNAL_SOURCES
+]
+
+
+class AuthSourceGatingTestCase(BaseTestGenerator):
+    """Checks AuthSourceRegistry.load_modules() honours config.SERVER_MODE."""
+
+    scenarios = [
+        ('desktop mode registers internal authentication only',
+         dict(server_mode=False)),
+        ('server mode registers every external provider',
+         dict(server_mode=True)),
+    ]
+
+    # Pure registry-contract test - no Postgres server interaction needed, so
+    # skip BaseTestGenerator.setUp's connect_server().
+    def setUp(self):
+        self._orig_server_mode = config.SERVER_MODE
+        self._orig_registry = dict(AuthSourceRegistry._registry or {})
+        self._orig_objects = dict(AuthSourceRegistry._objects or {})
+
+    def tearDown(self):
+        config.SERVER_MODE = self._orig_server_mode
+        AuthSourceRegistry._registry = self._orig_registry
+        AuthSourceRegistry._objects = self._orig_objects
+
+    def _reset_registry(self):
+        """Empty the registry and drop the external provider modules, so that
+        load_modules() is observed importing them (or not) from scratch.
+        """
+        for module in EXTERNAL_MODULES:
+            sys.modules.pop(module, None)
+
+        AuthSourceRegistry._registry = dict()
+        AuthSourceRegistry._objects = dict()
+
+        internal = sys.modules.get('pgadmin.authenticate.internal')
+        if internal is not None and \
+                hasattr(internal, 'InternalAuthentication'):
+            AuthSourceRegistry._registry['internal'] = \
+                internal.InternalAuthentication
+
+    def runTest(self):
+        config.SERVER_MODE = self.server_mode
+        self._reset_registry()
+
+        AuthSourceRegistry.load_modules(_MockApp() if self.server_mode
+                                        else None)
+
+        registered = list(AuthSourceRegistry._registry.keys())
+        self.assertIn(
+            'internal', registered,
+            "Internal authentication must be registered in both modes")
+
+        for source, module in zip(EXTERNAL_SOURCES, EXTERNAL_MODULES):
+            if self.server_mode:
+                self.assertIn(
+                    source, registered,
+                    "{0} must be registered in server mode".format(source))
+                self.assertIn(
+                    module, sys.modules,
+                    "{0} must be imported in server mode".format(module))
+            else:
+                self.assertNotIn(
+                    source, registered,
+                    "{0} must not be registered in desktop mode".format(
+                        source))
+                self.assertNotIn(
+                    module, sys.modules,
+                    "{0} must not be imported in desktop mode".format(module))
+
+
+class _MockApp:
+    """The minimum Flask-like surface the providers' init_app() touches."""
+
+    class _LoginManager:
+        logout_view = None
+
+    class _Logger:
+        def warning(self, *args, **kwargs):
+            pass
+
+    def __init__(self):
+        self.login_manager = self._LoginManager()
+        self.logger = self._Logger()
+
+    def register_blueprint(self, *args, **kwargs):
+        pass
+
+    def register_logout_hook(self, *args, **kwargs):
+        pass