Error cannot specify both conf_target and fee_rate - when it is not actually specified #23588

Version 22.0 Problem. When trying to send a transaction request to ./bitcoind with an explicit indication of the commission, an error occurs

{
   "jsonrpc":"1.0",
   "id":"AP",
   "method":"sendtoaddress",
   "params":[
      "tb1ql7w62elx9ucw4pj5lgw4l028hmuw80sndtntxt",
      "0.00002",
      "comment",
      "",
      false,
      false,
      null,
      "unset",
      false,
      "0.00001488"
   ]
}

The following options were also tried:

{
   "jsonrpc":"1.0",
   "id":"API",
   "method":"sendtoaddress",
   "params":[
      "tb1ql7w62elx9ucw4pj5lgw4l028hmuw80sndtntxt",
      "0.00002",
      "comment",
      "",
      false,
      false,
      -1,
      "unset",
      false,
      "0.00001488"
   ]
}

and

{
   "jsonrpc":"1.0",
   "id":"API lottery",
   "method":"sendtoaddress",
   "params":[
      "tb1ql7w62elx9ucw4pj5lgw4l028hmuw80sndtntxt",
      "0.00002",
      "comment",
      "",
      false,
      false,
      0,
      "unset",
      false,
      "0.00001488"
   ]
}

Getting any of the above JSON bitcoin thinks that conf_target is full when in fact it is not. Which is why I can't specify fee_rate at the very end. if you remove conf_target from json altogether, then the order of the parser is violated and it parses the fields incorrectly. An error will be received in all three requests:

Cannot specify both conf_target and fee_rate. Please provide either a confirmation target in blocks for automatic fee estimation, or an explicit fee rate.

Expected behavior: Sending a transaction with a fixed commission (0.00001488) specified in the request

Playback:

$ ./bitcoind -testnet

curl --user master --data-binary '{"jsonrpc":"1.0","id":"API","method":"sendtoaddress","params":["tb1ql7w62elx9ucw4pj5lgw4l028hmuw80sndtntxt","0.00002","comment","",false,false,0,"unset",false,"0.00001488"]}' -H 'content-type: text/plain;' http://127.0.0.1:18332/

When asking this question, I was guided by the documentation on the official website, which by the way does not contain a description of some fields, does not have an example of curl and needs to be updated. So for example there are examples with the fee_rate field, but not where there is no description of it.

Hey, will anyone respond to this problem? :)

You need to use null in JSON to specify unused arguments (or use named style, as use an object of "name":values for just the intended arguments instead of an array of arguments).

I think OP tried to set null (json) and it didn't work?

Yes it seems to have worked at last. Thank you very much. You can answer one more small but related question about commissions. I want to set a fixed commission to know the exact expense before I send the transaction to the network. I set the commission 2000 the commission amount is multiplied by the number of 141 bytes and the commission will be 0.00282000 BTC. how do I find out the transaction size? to know the actual commission amount?