Submitted by 0xluk3
The usernames module allows for registering a domain. This happens in function register_domain. On registration, a NFT is minted to the buyer, with field Token ID in format domain:timestamp. However the : character is forbidden by underlying nft.move module which is also the reason why original unit tests fail. 
Due to this, the protocol cannot be used in its current state, because no NFTs can be currently minted, thus, no domains can be claimed. Hence, this is equivalent to a permanent DoS. 
In register_domain, the name string is being appended .init:timestamp in line 358-360.
Running original unit tests, e.g., initiad move test --log_level trace --path ./usernames-module -f end_to_end. a debug print was added in line 362: std::debug::print(&name);
Tracking back the error call stack:
This function is provided below:
In the second assertion it requires : to be NOT present in the token_id. index_of will be equal to len only if the searched character will not be present in the string.
Since the name is passed as 4th argument to mint_nft_object, which is defined as:
Then, using a : by default causes the NFT to be not issued and function reverts.
Using a simple PoC:
initiad move test --log_level trace --path ./usernames-module -f my_poc_just_register
Line 359 is changed:
Result:
Change the colon : to other separator.
andrew (Initia) confirmed and commented:
