Merge #21679: rpc: Keep default argument value in correct type

bee56c7 rpc: Check default value type againts argument type (João Barbosa)
f81ef43 rpc: Keep default argument value in correct type (João Barbosa)

Pull request description:

  Store default values of RPC arguments in the corresponding type instead of a string. The value is then serialized when the help output is needed. This change simplifies #20017.

  The following examples illustrates how to use the new `RPCArg::Default` and `RPCArg::DefaultHint`:

  ```diff
  - {"verbose", RPCArg::Type::BOOL, /* default */ "false", "True for a json object, false for array of transaction ids"}
  + {"verbose", RPCArg::Type::BOOL, RPCArg::Default(false), "True for a json object, false for array of transaction ids"}
  ```

  ```diff
  - {"nblocks", RPCArg::Type::NUM, /* default */ "one month", "Size of the window in number of blocks"}
  + {"nblocks", RPCArg::Type::NUM, RPCArg::DefaultHint("one month"), "Size of the window in number of blocks"}
  ```

  No behavior change is expected.

ACKs for top commit:
  LarryRuane:
    ACK bee56c7
  MarcoFalke:
    ACK bee56c7 🦅

Tree-SHA512: c47d78c918e996d36631d4ad3c933b270a34c5b446b8d736be94cf4a0a7b8c0e33d954149ec786cf9550639865b79deb6a130ad044de6030f95aac33f524293a

Author: MarcoFalke

src/rpc/blockchain.cpp

@@ -254,7 +254,7 @@ static RPCHelpMan waitfornewblock()
                 "\nWaits for a specific new block and returns useful info about it.\n"
                 "\nReturns the current block on timeout or exit.\n",
                 {
-                    {"timeout", RPCArg::Type::NUM, /* default */ "0", "Time in milliseconds to wait for a response. 0 indicates no timeout."},
+                    {"timeout", RPCArg::Type::NUM, RPCArg::Default{0}, "Time in milliseconds to wait for a response. 0 indicates no timeout."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -297,7 +297,7 @@ static RPCHelpMan waitforblock()
                 "\nReturns the current block on timeout or exit.\n",
                 {
                     {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "Block hash to wait for."},
-                    {"timeout", RPCArg::Type::NUM, /* default */ "0", "Time in milliseconds to wait for a response. 0 indicates no timeout."},
+                    {"timeout", RPCArg::Type::NUM, RPCArg::Default{0}, "Time in milliseconds to wait for a response. 0 indicates no timeout."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -344,7 +344,7 @@ static RPCHelpMan waitforblockheight()
                 "\nReturns the current block on timeout or exit.\n",
                 {
                     {"height", RPCArg::Type::NUM, RPCArg::Optional::NO, "Block height to wait for."},
-                    {"timeout", RPCArg::Type::NUM, /* default */ "0", "Time in milliseconds to wait for a response. 0 indicates no timeout."},
+                    {"timeout", RPCArg::Type::NUM, RPCArg::Default{0}, "Time in milliseconds to wait for a response. 0 indicates no timeout."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -558,8 +558,8 @@ static RPCHelpMan getrawmempool()
                 "\nReturns all transaction ids in memory pool as a json array of string transaction ids.\n"
                 "\nHint: use getmempoolentry to fetch a specific transaction from the mempool.\n",
                 {
-                    {"verbose", RPCArg::Type::BOOL, /* default */ "false", "True for a json object, false for array of transaction ids"},
-                    {"mempool_sequence", RPCArg::Type::BOOL, /* default */ "false", "If verbose=false, returns a json object with transaction list and mempool sequence number attached."},
+                    {"verbose", RPCArg::Type::BOOL, RPCArg::Default{false}, "True for a json object, false for array of transaction ids"},
+                    {"mempool_sequence", RPCArg::Type::BOOL, RPCArg::Default{false}, "If verbose=false, returns a json object with transaction list and mempool sequence number attached."},
                 },
                 {
                     RPCResult{"for verbose = false",
@@ -608,7 +608,7 @@ static RPCHelpMan getmempoolancestors()
                 "\nIf txid is in the mempool, returns all in-mempool ancestors.\n",
                 {
                     {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id (must be in mempool)"},
-                    {"verbose", RPCArg::Type::BOOL, /* default */ "false", "True for a json object, false for array of transaction ids"},
+                    {"verbose", RPCArg::Type::BOOL, RPCArg::Default{false}, "True for a json object, false for array of transaction ids"},
                 },
                 {
                     RPCResult{"for verbose = false",
@@ -672,7 +672,7 @@ static RPCHelpMan getmempooldescendants()
                 "\nIf txid is in the mempool, returns all in-mempool descendants.\n",
                 {
                     {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id (must be in mempool)"},
-                    {"verbose", RPCArg::Type::BOOL, /* default */ "false", "True for a json object, false for array of transaction ids"},
+                    {"verbose", RPCArg::Type::BOOL, RPCArg::Default{false}, "True for a json object, false for array of transaction ids"},
                 },
                 {
                     RPCResult{"for verbose = false",
@@ -800,7 +800,7 @@ static RPCHelpMan getblockheader()
                 "If verbose is true, returns an Object with information about blockheader <hash>.\n",
                 {
                     {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The block hash"},
-                    {"verbose", RPCArg::Type::BOOL, /* default */ "true", "true for a json object, false for the hex-encoded data"},
+                    {"verbose", RPCArg::Type::BOOL, RPCArg::Default{true}, "true for a json object, false for the hex-encoded data"},
                 },
                 {
                     RPCResult{"for verbose = true",
@@ -902,7 +902,7 @@ static RPCHelpMan getblock()
                 "If verbosity is 2, returns an Object with information about block <hash> and information about each transaction. \n",
                 {
                     {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The block hash"},
-                    {"verbosity|verbose", RPCArg::Type::NUM, /* default */ "1", "0 for hex-encoded data, 1 for a json object, and 2 for json object with transaction data"},
+                    {"verbosity|verbose", RPCArg::Type::NUM, RPCArg::Default{1}, "0 for hex-encoded data, 1 for a json object, and 2 for json object with transaction data"},
                 },
                 {
                     RPCResult{"for verbosity = 0",
@@ -1070,7 +1070,7 @@ static RPCHelpMan gettxoutsetinfo()
                 "\nReturns statistics about the unspent transaction output set.\n"
                 "Note this call may take some time.\n",
                 {
-                    {"hash_type", RPCArg::Type::STR, /* default */ "hash_serialized_2", "Which UTXO set hash should be calculated. Options: 'hash_serialized_2' (the legacy algorithm), 'muhash', 'none'."},
+                    {"hash_type", RPCArg::Type::STR, RPCArg::Default{"hash_serialized_2"}, "Which UTXO set hash should be calculated. Options: 'hash_serialized_2' (the legacy algorithm), 'muhash', 'none'."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -1137,7 +1137,7 @@ static RPCHelpMan gettxout()
         {
             {"txid", RPCArg::Type::STR, RPCArg::Optional::NO, "The transaction id"},
             {"n", RPCArg::Type::NUM, RPCArg::Optional::NO, "vout number"},
-            {"include_mempool", RPCArg::Type::BOOL, /* default */ "true", "Whether to include the mempool. Note that an unspent output that is spent in the mempool won't appear."},
+            {"include_mempool", RPCArg::Type::BOOL, RPCArg::Default{true}, "Whether to include the mempool. Note that an unspent output that is spent in the mempool won't appear."},
         },
         {
             RPCResult{"If the UTXO was not found", RPCResult::Type::NONE, "", ""},
@@ -1220,9 +1220,9 @@ static RPCHelpMan verifychain()
     return RPCHelpMan{"verifychain",
                 "\nVerifies blockchain database.\n",
                 {
-                    {"checklevel", RPCArg::Type::NUM, /* default */ strprintf("%d, range=0-4", DEFAULT_CHECKLEVEL),
+                    {"checklevel", RPCArg::Type::NUM, RPCArg::DefaultHint{strprintf("%d, range=0-4", DEFAULT_CHECKLEVEL)},
                         strprintf("How thorough the block verification is:\n - %s", Join(CHECKLEVEL_DOC, "\n- "))},
-                    {"nblocks", RPCArg::Type::NUM, /* default */ strprintf("%d, 0=all", DEFAULT_CHECKBLOCKS), "The number of blocks to check."},
+                    {"nblocks", RPCArg::Type::NUM, RPCArg::DefaultHint{strprintf("%d, 0=all", DEFAULT_CHECKBLOCKS)}, "The number of blocks to check."},
                 },
                 RPCResult{
                     RPCResult::Type::BOOL, "", "Verified or not"},
@@ -1704,8 +1704,8 @@ static RPCHelpMan getchaintxstats()
     return RPCHelpMan{"getchaintxstats",
                 "\nCompute statistics about the total number and rate of transactions in the chain.\n",
                 {
-                    {"nblocks", RPCArg::Type::NUM, /* default */ "one month", "Size of the window in number of blocks"},
-                    {"blockhash", RPCArg::Type::STR_HEX, /* default */ "chain tip", "The hash of the block that ends the window."},
+                    {"nblocks", RPCArg::Type::NUM, RPCArg::DefaultHint{"one month"}, "Size of the window in number of blocks"},
+                    {"blockhash", RPCArg::Type::STR_HEX, RPCArg::DefaultHint{"chain tip"}, "The hash of the block that ends the window."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -1852,7 +1852,7 @@ static RPCHelpMan getblockstats()
                 "It won't work for some heights with pruning.\n",
                 {
                     {"hash_or_height", RPCArg::Type::NUM, RPCArg::Optional::NO, "The block hash or height of the target block", "", {"", "string or numeric"}},
-                    {"stats", RPCArg::Type::ARR, /* default */ "all values", "Values to plot (see result below)",
+                    {"stats", RPCArg::Type::ARR, RPCArg::DefaultHint{"all values"}, "Values to plot (see result below)",
                         {
                             {"height", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "Selected statistic"},
                             {"time", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "Selected statistic"},
@@ -2221,7 +2221,7 @@ static RPCHelpMan scantxoutset()
                 {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "An object with output descriptor and metadata",
                 {
                     {"desc", RPCArg::Type::STR, RPCArg::Optional::NO, "An output descriptor"},
-                    {"range", RPCArg::Type::RANGE, /* default */ "1000", "The range of HD chain indexes to explore (either end or [begin,end])"},
+                    {"range", RPCArg::Type::RANGE, RPCArg::Default{1000}, "The range of HD chain indexes to explore (either end or [begin,end])"},
                 }},
             },
                         "[scanobjects,...]"},
@@ -2360,7 +2360,7 @@ static RPCHelpMan getblockfilter()
                 "\nRetrieve a BIP 157 content filter for a particular block.\n",
                 {
                     {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The hash of the block"},
-                    {"filtertype", RPCArg::Type::STR, /*default*/ "basic", "The type name of the filter"},
+                    {"filtertype", RPCArg::Type::STR, RPCArg::Default{"basic"}, "The type name of the filter"},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",

src/rpc/mining.cpp

@@ -89,8 +89,8 @@ static RPCHelpMan getnetworkhashps()
                 "Pass in [blocks] to override # of blocks, -1 specifies since last difficulty change.\n"
                 "Pass in [height] to estimate the network speed at the time when a certain block was found.\n",
                 {
-                    {"nblocks", RPCArg::Type::NUM, /* default */ "120", "The number of blocks, or -1 for blocks since last difficulty change."},
-                    {"height", RPCArg::Type::NUM, /* default */ "-1", "To estimate at the time of the given height."},
+                    {"nblocks", RPCArg::Type::NUM, RPCArg::Default{120}, "The number of blocks, or -1 for blocks since last difficulty change."},
+                    {"height", RPCArg::Type::NUM, RPCArg::Default{-1}, "To estimate at the time of the given height."},
                 },
                 RPCResult{
                     RPCResult::Type::NUM, "", "Hashes per second estimated"},
@@ -214,7 +214,7 @@ static RPCHelpMan generatetodescriptor()
         {
             {"num_blocks", RPCArg::Type::NUM, RPCArg::Optional::NO, "How many blocks are generated immediately."},
             {"descriptor", RPCArg::Type::STR, RPCArg::Optional::NO, "The descriptor to send the newly generated bitcoin to."},
-            {"maxtries", RPCArg::Type::NUM, /* default */ ToString(DEFAULT_MAX_TRIES), "How many iterations to try."},
+            {"maxtries", RPCArg::Type::NUM, RPCArg::Default{DEFAULT_MAX_TRIES}, "How many iterations to try."},
         },
         RPCResult{
             RPCResult::Type::ARR, "", "hashes of blocks generated",
@@ -258,7 +258,7 @@ static RPCHelpMan generatetoaddress()
                 {
                     {"nblocks", RPCArg::Type::NUM, RPCArg::Optional::NO, "How many blocks are generated immediately."},
                     {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The address to send the newly generated bitcoin to."},
-                    {"maxtries", RPCArg::Type::NUM, /* default */ ToString(DEFAULT_MAX_TRIES), "How many iterations to try."},
+                    {"maxtries", RPCArg::Type::NUM, RPCArg::Default{DEFAULT_MAX_TRIES}, "How many iterations to try."},
                 },
                 RPCResult{
                     RPCResult::Type::ARR, "", "hashes of blocks generated",
@@ -525,7 +525,7 @@ static RPCHelpMan getblocktemplate()
         "    https://github.com/bitcoin/bips/blob/master/bip-0009.mediawiki#getblocktemplate_changes\n"
         "    https://github.com/bitcoin/bips/blob/master/bip-0145.mediawiki\n",
         {
-            {"template_request", RPCArg::Type::OBJ, "{}", "Format of the template",
+            {"template_request", RPCArg::Type::OBJ, RPCArg::Default{UniValue::VOBJ}, "Format of the template",
             {
                 {"mode", RPCArg::Type::STR, /* treat as named arg */ RPCArg::Optional::OMITTED_NAMED_ARG, "This must be set to \"template\", \"proposal\" (see BIP 23), or omitted"},
                 {"capabilities", RPCArg::Type::ARR, /* treat as named arg */ RPCArg::Optional::OMITTED_NAMED_ARG, "A list of strings",
@@ -960,7 +960,7 @@ static RPCHelpMan submitblock()
         "See https://en.bitcoin.it/wiki/BIP_0022 for full specification.\n",
         {
             {"hexdata", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "the hex-encoded block data to submit"},
-            {"dummy", RPCArg::Type::STR, /* default */ "ignored", "dummy value, for compatibility with BIP22. This value is ignored."},
+            {"dummy", RPCArg::Type::STR, RPCArg::DefaultHint{"ignored"}, "dummy value, for compatibility with BIP22. This value is ignored."},
         },
         {
             RPCResult{"If the block was accepted", RPCResult::Type::NONE, "", ""},
@@ -1069,7 +1069,7 @@ static RPCHelpMan estimatesmartfee()
         "in BIP 141 (witness data is discounted).\n",
         {
             {"conf_target", RPCArg::Type::NUM, RPCArg::Optional::NO, "Confirmation target in blocks (1 - 1008)"},
-            {"estimate_mode", RPCArg::Type::STR, /* default */ "conservative", "The fee estimate mode.\n"
+            {"estimate_mode", RPCArg::Type::STR, RPCArg::Default{"conservative"}, "The fee estimate mode.\n"
             "                   Whether to return a more conservative estimate which also satisfies\n"
             "                   a longer history. A conservative estimate potentially returns a\n"
             "                   higher feerate and is more likely to be sufficient for the desired\n"
@@ -1140,7 +1140,7 @@ static RPCHelpMan estimaterawfee()
                 "defined in BIP 141 (witness data is discounted).\n",
                 {
                     {"conf_target", RPCArg::Type::NUM, RPCArg::Optional::NO, "Confirmation target in blocks (1 - 1008)"},
-                    {"threshold", RPCArg::Type::NUM, /* default */ "0.95", "The proportion of transactions in a given feerate range that must have been\n"
+                    {"threshold", RPCArg::Type::NUM, RPCArg::Default{0.95}, "The proportion of transactions in a given feerate range that must have been\n"
             "               confirmed within conf_target in order to consider those feerates as high enough and proceed to check\n"
             "               lower buckets."},
                 },

src/rpc/misc.cpp

@@ -90,7 +90,7 @@ static RPCHelpMan createmultisig()
                         {
                             {"key", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "The hex-encoded public key"},
                         }},
-                    {"address_type", RPCArg::Type::STR, /* default */ "legacy", "The address type to use. Options are \"legacy\", \"p2sh-segwit\", and \"bech32\"."},
+                    {"address_type", RPCArg::Type::STR, RPCArg::Default{"legacy"}, "The address type to use. Options are \"legacy\", \"p2sh-segwit\", and \"bech32\"."},
                 },
                 RPCResult{
                     RPCResult::Type::OBJ, "", "",
@@ -475,7 +475,7 @@ static RPCHelpMan getmemoryinfo()
     return RPCHelpMan{"getmemoryinfo",
                 "Returns an object containing information about memory usage.\n",
                 {
-                    {"mode", RPCArg::Type::STR, /* default */ "\"stats\"", "determines what kind of information is returned.\n"
+                    {"mode", RPCArg::Type::STR, RPCArg::Default{"stats"}, "determines what kind of information is returned.\n"
             "  - \"stats\" returns general statistics about memory usage in the daemon.\n"
             "  - \"mallocinfo\" returns an XML string describing low-level heap state (only available if compiled with glibc 2.10+)."},
                 },