[KeyVault] Fix error message to reference the actual vault name option

src/azure-cli/azure/cli/command_modules/keyvault/_validators.py

@@ -131,14 +131,28 @@ def process_hsm_name(ns):
         ns.hsm_name = ns.identifier
 
 
+def _get_vault_name_options(ns):
+    """Get the option string of the vault name argument registered for the current command,
+    as it can be either --vault-name or --name/-n."""
+    default_options = '--vault-name'
+    cmd = getattr(ns, 'cmd', None)
+    arguments = getattr(cmd, 'arguments', None) or {}
+    argument = arguments.get('vault_name', None)
+    options_list = argument.options_list if argument else None
+    if not options_list:
+        return default_options
+    return '/'.join([str(option) for option in options_list])
+
+
 def validate_vault_name_and_hsm_name(ns):
     vault_name = getattr(ns, 'vault_name', None)
     hsm_name = getattr(ns, 'hsm_name', None)
+    vault_name_options = _get_vault_name_options(ns)
     if vault_name and hsm_name:
-        raise CLIError('--vault-name and --hsm-name are mutually exclusive.')
+        raise CLIError('{} and --hsm-name are mutually exclusive.'.format(vault_name_options))
 
     if not vault_name and not hsm_name:
-        raise CLIError('Please specify --vault-name or --hsm-name.')
+        raise CLIError('Please specify {} or --hsm-name.'.format(vault_name_options))
 
 # PARAMETER NAMESPACE VALIDATORS
 
@@ -426,7 +440,7 @@ def validate_deleted_vault_or_hsm_name(cmd, ns):
     hsm_name = getattr(ns, 'hsm_name', None)
 
     if not vault_name and not hsm_name:
-        raise CLIError('Please specify --vault-name or --hsm-name.')
+        raise CLIError('Please specify {} or --hsm-name.'.format(_get_vault_name_options(ns)))
 
     if vault_name:
         resource_name = vault_name

src/azure-cli/azure/cli/command_modules/keyvault/tests/latest/test_validators.py

@@ -0,0 +1,60 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+
+import unittest
+
+from knack.arguments import CLICommandArgument
+from knack.util import CLIError
+
+from azure.cli.command_modules.keyvault._validators import (
+    validate_deleted_vault_or_hsm_name,
+    validate_vault_name_and_hsm_name,
+)
+
+
+class _Command:
+    def __init__(self, vault_name_options):
+        self.arguments = {
+            'vault_name': CLICommandArgument('vault_name', options_list=vault_name_options)
+        }
+
+
+class _Namespace:
+    def __init__(self, vault_name_options=None, vault_name=None, hsm_name=None):
+        if vault_name_options:
+            self.cmd = _Command(vault_name_options)
+        self.vault_name = vault_name
+        self.hsm_name = hsm_name
+
+
+class KeyVaultValidatorsTest(unittest.TestCase):
+    def test_validate_vault_name_and_hsm_name(self):
+        # the error message should match the option registered for the command
+        with self.assertRaisesRegex(CLIError, r'Please specify --name/-n or --hsm-name\.'):
+            validate_vault_name_and_hsm_name(_Namespace(vault_name_options=['--name', '-n']))
+
+        with self.assertRaisesRegex(CLIError, r'--name/-n and --hsm-name are mutually exclusive\.'):
+            validate_vault_name_and_hsm_name(
+                _Namespace(vault_name_options=['--name', '-n'], vault_name='vault', hsm_name='hsm'))
+
+        with self.assertRaisesRegex(CLIError, r'Please specify --vault-name or --hsm-name\.'):
+            validate_vault_name_and_hsm_name(_Namespace(vault_name_options=['--vault-name']))
+
+        # fall back to --vault-name when the vault name argument can't be resolved
+        with self.assertRaisesRegex(CLIError, r'Please specify --vault-name or --hsm-name\.'):
+            validate_vault_name_and_hsm_name(_Namespace())
+
+        # no exception when just one of them is specified
+        validate_vault_name_and_hsm_name(_Namespace(vault_name_options=['--name', '-n'], vault_name='vault'))
+        validate_vault_name_and_hsm_name(_Namespace(vault_name_options=['--name', '-n'], hsm_name='hsm'))
+
+    def test_validate_deleted_vault_or_hsm_name(self):
+        ns = _Namespace(vault_name_options=['--name', '-n'])
+        with self.assertRaisesRegex(CLIError, r'Please specify --name/-n or --hsm-name\.'):
+            validate_deleted_vault_or_hsm_name(ns.cmd, ns)
+
+
+if __name__ == '__main__':
+    unittest.main()