fix(cli): resolve transfer struct via action type in sync-accounts (get_tokens missing balances)

[igorls]

Problem

Operators report /v2/state/get_tokens returning an incomplete token list after upgrading (e.g. bu.klnk shows 13/37 tokens), with the tell-tale symptom that some symbols of the same contract show while others are missing.

Root cause

AccountSynchronizer.scanABIs() decides whether a contract is a token contract before backfilling balances. It looked up the transfer parameter struct by the hard-coded struct name "transfer":

const transferType = abi.abi?.structs?.find(s => s.name === 'transfer');

Per the ABI spec, the struct backing an action is named by the action's type field, which is frequently not the action name. Several real token contracts declare a fully standard transfer (from:name, to:name, quantity:asset, memo:string) under a differently-named struct — e.g. the paycash contracts use transfer_token. For those, the lookup returned undefined, the field validation never ran, and the contract was silently skipped → its balances were never backfilled into the MongoDB accounts collection.

The live indexer's *:accounts handler has no such requirement, so it captured whatever balances changed post-upgrade — hence "same contract, some symbols present, some missing."

Fix

Resolve the transfer struct through the transfer action's declared type, and guard against short field arrays.

Verification (against api.eosrio.io)

Applying the old vs new detection to the contracts held by bu.klnk + a sample from eosriobrazil:

• current: accepts 12/22
• fixed: accepts 22/22
• recovered (current SKIP → now accept): cashescashes, token.pcash, swap.pcash, jqpua4jqkqwz, testnewswap1, testrenminbi, testrublesrb, testuralsurl, uralsuralsru, testusdbxusd

All recovered contracts have accounts+stat tables, an accounts row of balance:asset, and a transfer action whose transfer_token struct is exactly from,to,quantity,memo. Standard-transfer contracts are unaffected. tsc --noEmit passes.

Operator action after merge

Pull, rebuild, then re-run ./hyp-control sync accounts <chain> (or sync all <chain>) to backfill the previously skipped contracts.

[gemini-code-assist]

Code Review

This pull request fixes an issue where token contracts were skipped during account synchronization by resolving the transfer parameter struct using the action's declared type instead of a hard-coded name. It also adds safety checks to prevent out-of-bounds errors when validating fields. The reviewer suggested a code improvement to simplify and secure the field validation check by directly comparing the field name with the expected name.

[gemini-code-assist]

The current check allows any field at index i to be accepted as valid if its name is either "from" or "to" and its type is "account_name", regardless of whether the index matches the expected field name (e.g., if from and to are swapped, or if a different field is named "from").

Since transferFields[i].name already contains the expected name ("from" at index 0, "to" at index 1), we can simplify and secure this check by verifying that fields[i].name matches transferFields[i].name directly.

Suggested change

	if (fields[i] && (fields[i].name === "from" || fields[i].name === "to") && fields[i].type === 'account_name') {
	valid = true;
	continue;
	}
	if (fields[i] && fields[i].name === transferFields[i].name && fields[i].type === 'account_name') {
	valid = true;
	continue;
	}

[igorls]

Good catch — applied in 584db2b. Matching transferFields[i].name positionally (consistent with the standard-type branch). Verified no behavior change for real contracts (still 22/22 accepted against api.eosrio.io); it only rejects malformed/swapped ABIs.