[azure-mgmt-core] is_valid_resource_id returns True for invalid resource IDs

[jiasli]

Is your feature request related to a problem? Please describe.
In Azure/azure-cli#10641 (comment), Azure CLI receives an incorrect --scope /subscriptions/{subscription_id}/resourceGroups/ which lacks the resource group name. It gets injected into the resource URL, thus corrupting the command.

In order to fix it, I try to use azure.mgmt.core.tools.is_valid_resource_id to detect whether a scope is valid:

azure-sdk-for-python/sdk/core/azure-mgmt-core/azure/mgmt/core/tools.py

Line 195 in adf6471

def is_valid_resource_id(rid, exception_type=None):

Unfortunately, is_valid_resource_id can't return the correct value for some edge cases like this.

A code snippet:

from azure.mgmt.core.tools import parse_resource_id, is_valid_resource_id

res_ids = ['/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/rg1',
           '/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups',
           '/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/',
           '/subscriptions//resourceGroups/']

for res_id in res_ids:
    print(res_id)
    print(parse_resource_id(res_id))
    print(is_valid_resource_id(res_id))
    print()

Output:

/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/rg1
{'subscription': '0b1f6471-1bf0-4dda-aec3-cb9272f09590', 'resource_group': 'rg1'}
True

/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups
{'subscription': '0b1f6471-1bf0-4dda-aec3-cb9272f09590'}
False

# The trailing slash makes is_valid_resource_id return True
/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/
{'subscription': '0b1f6471-1bf0-4dda-aec3-cb9272f09590', 'resource_group': ''}
True

# Empty subscription ID shouldn't be allowed
/subscriptions//resourceGroups/
{'subscription': '', 'resource_group': ''}
True

Describe the solution you'd like

1. No empty name '' should be allowed when parsing a resource ID
2. is_valid_resource_id should return False for /subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/

[lmazuel]

Hi @jiasli
This part of the code has been written by the CLI team back in the days in msrestazure, and I ported it as-is in azure-mgmt-core. I have no knowledge of it, and also @RodgeFu told me that @changlong-liu will now take care of azure-mgmt-core.
Thanks!