Omitting optional type in vec breaks

[lastmjs]

I have this Candid type taken as an argument to the initialization of a canister:

type InitArgs = record {
    "decimals": nat8;
    "fee": nat;
    "initial_account_balances": vec InitialAccountBalance;
    "metadata": vec Metadatum;
    "minting_account": opt Account;
    "name": text;
    "permitted_drift_nanos": opt nat64;
    "supported_standards": vec SupportedStandard;
    "symbol": text;
    "transaction_window_nanos": opt nat64;
};

If I try to deploy my canister with this Candid value:

record {
    decimals = 8 : nat8;
    fee = 0 : nat;
    initial_account_balances = vec {
        record {
            account = record {
                owner = principal "jm5gm-r5btc-kor5h-mkrva-sbubi-z2krh-3flug-4xr2v-bnkhf-w23cq-dae";
                subaccount = null;
            };
            balance = 100_000_000 : nat;
        };
        record {
            account = record {
                owner = principal "jm5gm-r5btc-kor5h-mkrva-sbubi-z2krh-3flug-4xr2v-bnkhf-w23cq-dae";
                subaccount = opt vec { 0 : nat8; 0 : nat8; 0 : nat8; 1 : nat8 };
            };
            balance = 200_000_000 : nat;
        };
    };
    metadata = vec {};
    minting_account = record {
        owner = principal "jkpmw-aav35-wxvb3-lanyp-62lqw-fmtwc-cvqc3-jcn7p-6jtrt-x7csr-rae";
    };
    name = "Azle";
    supported_standards = vec {};
    symbol = "AZLE";
}

then I receive this error:

Installing code for canister icrc_1, with canister ID rrkah-fqaaa-aaaaa-aaaaq-cai
Error: Failed to install wasm in canister 'rrkah-fqaaa-aaaaa-aaaaq-cai'.
Caused by: Failed to install wasm in canister 'rrkah-fqaaa-aaaaa-aaaaq-cai'.
  Failed to install wasm.
    The Replica returned an error: code 5, message: "Canister rrkah-fqaaa-aaaaa-aaaaq-cai trapped explicitly: Custom(Trailing value after finishing deserialization

Caused by:
    input: 4449444c066c08c6fcb6027dc295a993017befcee7800401aecbeb880402cbe4fdc7047185ccbc9c0e01d8def6f60e71c4c4f1810f036d6f6c01b3b0dac303686d046c029cbab69c027dadf9e78a0a056c02b3b0dac30368ad86ca83057f0100000800011d15df6d7a876b0370ff6970b1593b085580b69137eff26719dfe294620204417a6c650004415a4c450280c2d72f011da19894e8f4ec546a0906814674a89f655d0dcbc7550b5472db5b1406028084af5f011da19894e8f4ec546a0906814674a89f655d0dcbc7550b5472db5b140602_010400000001
    table: type table0 = record {
      5_094_982 : nat;
      308_955_842 : nat8;
      1_075_439_471 : table1;
      1_092_281_774 : table2;
      1_224_700_491 : text;
      3_817_809_413 : table1;
      4_007_505_752 : text;
      4_030_489_156 : table3;
    }
    type table1 = vec empty
    type table2 = record { 947_296_307 : principal }
    type table3 = vec table4
    type table4 = record { 596_483_356 : nat; 2_707_029_165 : table5 }
    type table5 = record { 947_296_307 : principal; 1_349_681_965 : null }
    wire_type: null, expect_type: opt vec nat8)"

If I instead omit subaccount in the first record in the initial_account_balances vec, I get this error:

Installing code for canister icrc_1, with canister ID rrkah-fqaaa-aaaaa-aaaaq-cai
Error: Failed to install wasm in canister 'rrkah-fqaaa-aaaaa-aaaaq-cai'.
Caused by: Failed to install wasm in canister 'rrkah-fqaaa-aaaaa-aaaaq-cai'.
  Failed to install wasm.
    The Replica returned an error: code 5, message: "Canister rrkah-fqaaa-aaaaa-aaaaq-cai trapped explicitly: Custom(Trailing value after finishing deserialization

Caused by:
    input: 4449444c056c08c6fcb6027dc295a993017befcee7800401aecbeb880402cbe4fdc7047185ccbc9c0e01d8def6f60e71c4c4f1810f036d6f6c01b3b0dac303686d046c029cbab69c027dadf9e78a0a020100000800011d15df6d7a876b0370ff6970b1593b085580b69137eff26719dfe294620204417a6c650004415a4c450280c2d72f011da19894e8f4ec546a0906814674a89f655d0dcbc7550b5472db5b1406028084af5f011da19894e8f4ec546a0906814674a89f655d0dcbc7550b5472db5b140602_010400000001
    table: type table0 = record {
      5_094_982 : nat;
      308_955_842 : nat8;
      1_075_439_471 : table1;
      1_092_281_774 : table2;
      1_224_700_491 : text;
      3_817_809_413 : table1;
      4_007_505_752 : text;
      4_030_489_156 : table3;
    }
    type table1 = vec empty
    type table2 = record { 947_296_307 : principal }
    type table3 = vec table4
    type table4 = record { 596_483_356 : nat; 2_707_029_165 : table2 }
    wire_type: reserved, expect_type: opt vec nat8)"

It's as if I can't have a null or omitted subaccount in one record while having an actual value in another. This seems like a bug.

[chenyan-dfinity]

How do you pass in the init args, via --argument in dfx? Is the init args type specified in the .did file? Something like service : (InitArgs) -> {...}. It looks like the type information is lost in the encoding somehow.