RPCHelpMan: Check default values are given at compile-time #14918

Remove the run time assertions on the default values and ensure that the correct default type and value is provided at compile time.

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The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

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Conflicts

Reviewers, this pull request conflicts with the following ones:

• #15341 (rpc: Support specifying change address in bumpfee by promag)
• #15006 (Add option to create an encrypted wallet by achow101)
• #14707 ([RPC] Include coinbase transactions in receivedby RPCs by andrewtoth)
• #14641 (rpc: Add min_conf option to fund transaction calls by promag)
• #14481 (Add P2SH-P2WSH support to listunspent RPC by MeshCollider)
• #13541 (wallet/rpc: sendrawtransaction maxfeerate by kallewoof)
• #12674 (RPC: Support addnode onetry without making the connection priviliged by luke-jr)
• #11484 (Optional update rescan option in importmulti RPC by pedrobranco)
• #10593 (Relax punishment for peers relaying invalid blocks and headers by luke-jr)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

@ryanofsky Mind to take a look here? You requested this in #14877#pullrequestreview-183308244

utACK fa0ad4e7ce8f4c19fe58bf06747bf8c62600581c

@ryanofsky Mind to take a look here? You requested this in #14877 (review)

This is a big monster change, but it does make things clearer. I reviewed the code and also diffed the output using #14726#pullrequestreview-175423309. All the changes looked like improvements.

<details><summary>Output</summary>

@@ -59,7 +59,7 @@
        "key",      (string) bitcoin address or hex-encoded public key
        ...
      ]
-3. label           (string, optional, default=null) A label to assign the addresses to.
+3. label           (string, optional) A label to assign the addresses to.
 4. address_type    (string, optional, default=set by -addresstype) The address type to use. Options are "legacy", "p2sh-segwit", and "bech32".
 
 Result:
@@ -121,7 +121,7 @@
 
 Arguments:
 1. txid                           (string, required) The txid to be bumped
-2. options                        (json object, optional, default=null)
+2. options                        (json object, optional)
      {
        "confTarget": n,           (numeric, optional, default=fallback to wallet's default) Confirmation target (in blocks)
        "totalFee": n,             (numeric, optional, default=fallback to 'confTarget') Total fee (NOT feerate) to pay, in satoshis.
@@ -782,7 +782,7 @@
 
 Arguments:
 1. hexstring                          (string, required) The hex string of the raw transaction
-2. options                            (json object, optional, default=null) for backward compatibility: passing in a true instead of an object will result in {"includeWatching":true}
+2. options                            (json object, optional) for backward compatibility: passing in a true instead of an object will result in {"includeWatching":true}
      {
        "changeAddress": "str",        (string, optional, default=pool address) The bitcoin address to receive the change
        "changePosition": n,           (numeric, optional, default=random) The index of the change output
@@ -972,7 +972,7 @@
 thus affected by options which limit spendability such as -spendzeroconfchange.
 
 Arguments:
-1. dummy                (string, optional, default=null) Remains for backward compatibility. Must be excluded or set to "*".
+1. dummy                (string, optional) Remains for backward compatibility. Must be excluded or set to "*".
 2. minconf              (numeric, optional, default=0) Only include transactions confirmed at least this many times.
 3. include_watchonly    (boolean, optional, default=false) Also include balance in watch-only addresses (see 'importaddress')
 
@@ -1682,7 +1682,7 @@
 so payments received with the address will be associated with 'label'.
 
 Arguments:
-1. label           (string, optional, default=null) The label name for the address to be linked to. If not provided, the default label "" is used. It can also be set to the empty string "" to represent the default label. The label does not need to exist, it will be created if there is no label by the given name.
+1. label           (string, optional, default="") The label name for the address to be linked to. It can also be set to the empty string "" to represent the default label. The label does not need to exist, it will be created if there is no label by the given name.
 2. address_type    (string, optional, default=set by -addresstype) The address type to use. Options are "legacy", "p2sh-segwit", and "bech32".
 
 Result:
@@ -1859,7 +1859,7 @@
 Arguments:
 1. txid         (string, required) The transaction id
 2. verbose      (boolean, optional, default=false) If false, return a string, otherwise return a json object
-3. blockhash    (string, optional, default=null) The block in which to look for the transaction
+3. blockhash    (string, optional) The block in which to look for the transaction
 
 Result (if verbose is not set or set to false):
 "data"      (string) The serialized, hex-encoded data for 'txid'
@@ -2080,7 +2080,7 @@
        "txid",    (string) A transaction hash
        ...
      ]
-2. blockhash      (string, optional, default=null) If specified, looks for txid in the block with this hash
+2. blockhash      (string, optional) If specified, looks for txid in the block with this hash
 
 Result:
 "data"           (string) A string that is a serialized, hex-encoded data for the proof.
@@ -2191,7 +2191,7 @@
 1. requests                                                         (json array, required) Data to be imported
      [
        {                                                            (json object)
-         "desc": "str",                                             (string, optional) Descriptor to import. If using descriptor, do not also provide address/scriptPubKey, scripts, or pubkeys
+         "desc": "str",                                             (string) Descriptor to import. If using descriptor, do not also provide address/scriptPubKey, scripts, or pubkeys
          "scriptPubKey": "<script>" | { "address":"<address>" },    (string / json, required) Type of scriptPubKey (string for script, json for address). Should not be provided if using a descriptor
          "timestamp": timestamp | "now",                            (integer / string, required) Creation time of the key in seconds since epoch (Jan 1 1970 GMT),
                                                                     or the string "now" to substitute the current synced blockchain time. The timestamp of the oldest
@@ -2199,8 +2199,8 @@
                                                                     "now" can be specified to bypass scanning, for keys which are known to never have been used, and
                                                                     0 can be specified to scan the entire blockchain. Blocks up to 2 hours before the earliest key
                                                                     creation time of all keys being imported by the importmulti call will be scanned.
-         "redeemscript": "str",                                     (string, optional, default=omitted) Allowed only if the scriptPubKey is a P2SH or P2SH-P2WSH address/scriptPubKey
-         "witnessscript": "str",                                    (string, optional, default=omitted) Allowed only if the scriptPubKey is a P2SH-P2WSH or P2WSH address/scriptPubKey
+         "redeemscript": "str",                                     (string) Allowed only if the scriptPubKey is a P2SH or P2SH-P2WSH address/scriptPubKey
+         "witnessscript": "str",                                    (string) Allowed only if the scriptPubKey is a P2SH-P2WSH or P2WSH address/scriptPubKey
          "pubkeys": [                                               (json array, optional, default=empty array) Array of strings giving pubkeys to import. They must occur in P2PKH or P2WPKH scripts. They are not required when the private key is also provided (see the "keys" argument).
            "pubKey",                                                (string)
            ...
@@ -2209,7 +2209,7 @@
            "key",                                                   (string)
            ...
          ],
-         {                                                          (json object, optional) If a ranged descriptor is used, this specifies the start and end of the range to import
+         {                                                          (json object) If a ranged descriptor is used, this specifies the start and end of the range to import
            "start": n,                                              (numeric, optional, default=0) Start of the range to import
            "end": n,                                                (numeric, required) End of the range to import (inclusive)
          },
@@ -2219,7 +2219,7 @@
        },
        ...
      ]
-2. options                                                          (json object, optional, default=null)
+2. options                                                          (json object, optional)
      {
        "rescan": bool,                                              (boolean, optional, default=true) Stating if should rescan the blockchain after all imports
      }
@@ -2379,7 +2379,7 @@
 Returns the list of all labels, or labels that are assigned to addresses with a specific purpose.
 
 Arguments:
-1. purpose    (string, optional, default=null) Address purpose to list labels for ('send','receive'). An empty string is the same as not providing this argument.
+1. purpose    (string, optional) Address purpose to list labels for ('send','receive'). An empty string is the same as not providing this argument.
 
 Result:
 [               (json array of string)
@@ -2442,7 +2442,7 @@
 1. minconf              (numeric, optional, default=1) The minimum number of confirmations before payments are included.
 2. include_empty        (boolean, optional, default=false) Whether to include addresses that haven't received any payments.
 3. include_watchonly    (boolean, optional, default=false) Whether to include watch-only addresses (see 'importaddress').
-4. address_filter       (string, optional, default=null) If present, only return information on this address.
+4. address_filter       (string, optional) If present, only return information on this address.
 
 Result:
 [
@@ -2500,7 +2500,7 @@
 Additionally, if include_removed is set, transactions affecting the wallet which were removed are returned in the "removed" array.
 
 Arguments:
-1. blockhash               (string, optional, default=null) If set, the block hash to list transactions since, otherwise list all transactions.
+1. blockhash               (string, optional) If set, the block hash to list transactions since, otherwise list all transactions.
 2. target_confirmations    (numeric, optional, default=1) Return the nth block hash from the main chain. e.g. 1 would mean the best block hash. Note: this is not used as a filter, but only affects [lastblock] in the return value
 3. include_watchonly       (boolean, optional, default=false) Include transactions to watch-only addresses (see 'importaddress')
 4. include_removed         (boolean, optional, default=true) Show transactions that were removed due to a reorg in the "removed" array
@@ -2555,7 +2555,7 @@
 Returns up to 'count' most recent transactions skipping the first 'from' transactions.
 
 Arguments:
-1. label                (string, optional, default=null) If set, should be a valid label name to return only incoming transactions
+1. label                (string, optional) If set, should be a valid label name to return only incoming transactions
                         with the specified label, or "*" to disable filtering and return all transactions.
 2. count                (numeric, optional, default=10) The number of transactions to return
 3. skip                 (numeric, optional, default=0) The number of transactions to skip
@@ -2622,7 +2622,7 @@
      ]
 4. include_unsafe                     (boolean, optional, default=true) Include outputs that are not safe to spend
                                       See description of "safe" attribute below.
-5. query_options                      (json object, optional, default=null) JSON with query options
+5. query_options                      (json object, optional) JSON with query options
      {
        "minimumAmount": amount,       (numeric or string, optional, default=0) Minimum value of each UTXO in BTC
        "maximumAmount": amount,       (numeric or string, optional, default=unlimited) Maximum value of each UTXO in BTC
@@ -2766,12 +2766,12 @@
   - "none", "0" : even if other logging categories are specified, ignore all of them.
 
 Arguments:
-1. include                    (json array, optional, default=null) A json array of categories to add debug logging
+1. include                    (json array, optional) A json array of categories to add debug logging
      [
        "include_category",    (string) the valid logging category
        ...
      ]
-2. exclude                    (json array, optional, default=null) A json array of categories to remove debug logging
+2. exclude                    (json array, optional) A json array of categories to remove debug logging
      [
        "exclude_category",    (string) the valid logging category
        ...
@@ -2820,7 +2820,7 @@
 
 Arguments:
 1. txid         (string, required) The transaction id.
-2. dummy        (numeric, optional, default=null) API-Compatibility for previous API. Must be zero or null.
+2. dummy        (numeric, optional) API-Compatibility for previous API. Must be zero or null.
                 DEPRECATED. For forward compatibility use named arguments and omit this parameter.
 3. fee_delta    (numeric, required) The fee value (in satoshis) to add (or subtract, if negative).
                 Note, that this value is not a fee rate. It is a value to modify absolute fee of the TX.
@@ -2975,8 +2975,8 @@
        "address": amount,    (numeric or string, required) The bitcoin address is the key, the numeric amount (can be string) in BTC is the value
      }
 3. minconf                   (numeric, optional, default=1) Only use the balance confirmed at least this many times.
-4. comment                   (string, optional, default=null) A comment
-5. subtractfeefrom           (json array, optional, default=null) A json array with addresses.
+4. comment                   (string, optional) A comment
+5. subtractfeefrom           (json array, optional) A json array with addresses.
                              The fee will be equally deducted from the amount of each selected address.
                              Those recipients will receive less bitcoins than you enter in their corresponding amount field.
                              If no addresses are specified here, the sender pays the fee.
@@ -3044,9 +3044,9 @@
 Arguments:
 1. address                  (string, required) The bitcoin address to send to.
 2. amount                   (numeric or string, required) The amount in BTC to send. eg 0.1
-3. comment                  (string, optional, default=null) A comment used to store what the transaction is for.
+3. comment                  (string, optional) A comment used to store what the transaction is for.
                             This is not part of the transaction, just kept in your wallet.
-4. comment_to               (string, optional, default=null) A comment to store the name of the person or organization
+4. comment_to               (string, optional) A comment to store the name of the person or organization
                             to which you're sending the transaction. This is not part of the 
                             transaction, just kept in your wallet.
 5. subtractfeefromamount    (boolean, optional, default=false) The fee will be deducted from the amount being sent.
@@ -3217,13 +3217,13 @@
        "privatekey",               (string) private key in base58-encoding
        ...
      ]
-3. prevtxs                         (json array, optional, default=null) A json array of previous dependent transaction outputs
+3. prevtxs                         (json array, optional) A json array of previous dependent transaction outputs
      [
        {                           (json object)
          "txid": "hex",            (string, required) The transaction id
          "vout": n,                (numeric, required) The output number
          "scriptPubKey": "hex",    (string, required) script key
-         "redeemScript": "hex",    (string, optional, default=omitted) (required for P2SH or P2WSH) redeem script
+         "redeemScript": "hex",    (string) (required for P2SH or P2WSH) redeem script
          "amount": amount,         (numeric or string, required) The amount spent
        },
        ...
@@ -3266,13 +3266,13 @@
 
 Arguments:
 1. hexstring                       (string, required) The transaction hex string
-2. prevtxs                         (json array, optional, default=null) A json array of previous dependent transaction outputs
+2. prevtxs                         (json array, optional) A json array of previous dependent transaction outputs
      [
        {                           (json object)
          "txid": "hex",            (string, required) The transaction id
          "vout": n,                (numeric, required) The output number
          "scriptPubKey": "hex",    (string, required) script key
-         "redeemScript": "hex",    (string, optional, default=omitted) (required for P2SH or P2WSH)
+         "redeemScript": "hex",    (string) (required for P2SH or P2WSH) redeem script
          "amount": amount,         (numeric or string, required) The amount spent
        },
        ...
@@ -3586,7 +3586,7 @@
        ...
      ]
 3. locktime                           (numeric, optional, default=0) Raw locktime. Non-0 value also locktime-activates inputs
-4. options                            (json object, optional, default=null)
+4. options                            (json object, optional)
      {
        "changeAddress": "hex",        (string, optional, default=pool address) The bitcoin address to receive the change
        "changePosition": n,           (numeric, optional, default=random) The index of the change output

</details>