fix: guard PasswordExec against None host/port/username

web/pgadmin/utils/passexec.py

@@ -39,10 +39,12 @@ def get(self):
             raise NotImplementedError('Passexec not available in server mode')
         driver = get_driver(config.PG_DEFAULT_DRIVER)
         self.cmd = str(self.cmd)
-        self.cmd = self.cmd.replace('%HOSTNAME%', self.host)
-        self.cmd = self.cmd.replace('%PORT%', str(self.port))
-        self.cmd = self.cmd.replace('%USERNAME%',
-                                    driver.qtIdent(None,self.username))
+        self.cmd = self.cmd.replace('%HOSTNAME%', self.host or '')
+        self.cmd = self.cmd.replace(
+            '%PORT%', str(self.port) if self.port is not None else '')
+        self.cmd = self.cmd.replace(
+            '%USERNAME%',
+            driver.qtIdent(None, self.username) if self.username else '')
         with self.lock:
             if not self.password or self.is_expired():
                 if not self.cmd:

web/pgadmin/utils/tests/test_passexec.py

@@ -0,0 +1,49 @@
+##########################################################################
+#
+# pgAdmin 4 - PostgreSQL Tools
+#
+# Copyright (C) 2013 - 2026, The pgAdmin Development Team
+# This software is released under the PostgreSQL Licence
+#
+##########################################################################
+
+"""Regression test for PasswordExec.get() with a Service-only connection.
+
+When a server is configured via the ``Service`` field (pg_service.conf) with
+host, port and username left blank, ``PasswordExec`` is constructed with
+those attributes as ``None``. ``get()`` used to pass them straight into
+``str.replace()``, which raises ``TypeError: replace() argument 2 must be
+str, not None``. The fix substitutes an empty string for any unset
+placeholder instead."""
+
+from unittest.mock import patch, MagicMock
+
+from pgadmin.utils.route import BaseTestGenerator
+from pgadmin.utils.passexec import PasswordExec
+
+
+class TestPasswordExecServiceOnly(BaseTestGenerator):
+    """PasswordExec.get() must not raise when host/port/username are None."""
+
+    def setUp(self):
+        pass
+
+    def runTest(self):
+        pexec = PasswordExec(
+            'echo %HOSTNAME%:%PORT%:%USERNAME%', None, None, None)
+
+        fake_driver = MagicMock()
+        fake_driver.qtIdent.return_value = 'quoted'
+        fake_proc = MagicMock(stdout='secret\n')
+
+        with self.app.app_context(), \
+                patch('pgadmin.utils.passexec.get_driver',
+                      return_value=fake_driver), \
+                patch('pgadmin.utils.passexec.subprocess.run',
+                      return_value=fake_proc) as mock_run, \
+                patch('pgadmin.utils.passexec.config.SERVER_MODE', False):
+            password = pexec.get()
+
+        self.assertEqual(password, 'secret')
+        self.assertEqual(mock_run.call_args[0][0], 'echo ::')
+        fake_driver.qtIdent.assert_not_called()