Merge #19644: rpc: document returned error fields as optional if applicable

f110b7c722eb150816a26cab161ac2b8c0f58609 rpc: document returned error fields as optional if applicable (Sebastian Falbesoner)

Pull request description:

  The following RPCs return error fields (named `"error"` or `"errors"`) that are optional, but don't show up as optional in the help text yet:
  * `analyzepsbt`
  * `estimatesmartfee`
  * `signrawtransactionwithkey`
  * `signrawtransactionwithwallet`

  The following RPC has the errors field already marked as optional, but doesn't match the usual format in the description (like `"if there are any"` in parantheses):
  * `estimaterawfee`

  This PR adds the missing optional flags and adapts the description strings. Inspired by a recent PR #19634 by justinmoon.

  The instances were found via `git grep "RPCResult.*\"error"`. Note that there is one RPC so far where the return error is not optional (i.e. in case of no error, the field is included in the result, but is just empty), namely `bumpfee`.

ACKs for top commit:
  adaminsky:
    ACK `f110b7c`
  laanwj:
    ACK f110b7c722eb150816a26cab161ac2b8c0f58609, new documentation looks consistent with actual behavior
  achow101:
    ACK f110b7c722eb150816a26cab161ac2b8c0f58609
  meshcollider:
    utACK f110b7c722eb150816a26cab161ac2b8c0f58609

Tree-SHA512: 30c00f78a575b60e32b4536496af986d53a25f33e6ebbf553adcdcf825ad21a44f90267f3d1ea53326dac83bcfa9983fdb3dad6d3126e20f97f3c08ce286e188

2 files changed, 4 insertions, 4 deletions

diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index fee6a893eb..2f849d6f4b 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -1019,7 +1019,7 @@ static UniValue estimatesmartfee(const JSONRPCRequest& request)
                     RPCResult::Type::OBJ, "", "",
                     {
                         {RPCResult::Type::NUM, "feerate", /* optional */ true, "estimate fee rate in " + CURRENCY_UNIT + "/kB (only present if no errors were encountered)"},
-                        {RPCResult::Type::ARR, "errors", "Errors encountered during processing",
+                        {RPCResult::Type::ARR, "errors", /* optional */ true, "Errors encountered during processing (if there are any)",
                             {
                                 {RPCResult::Type::STR, "", "error"},
                             }},
@@ -1098,7 +1098,7 @@ static UniValue estimaterawfee(const JSONRPCRequest& request)
                                 {
                                     {RPCResult::Type::ELISION, "", ""},
                                 }},
-                                {RPCResult::Type::ARR, "errors", /* optional */ true, "Errors encountered during processing",
+                                {RPCResult::Type::ARR, "errors", /* optional */ true, "Errors encountered during processing (if there are any)",
                                 {
                                     {RPCResult::Type::STR, "error", ""},
                                 }},
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 9b6ef15785..67ded27769 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -744,7 +744,7 @@ static UniValue signrawtransactionwithkey(const JSONRPCRequest& request)
                     {
                         {RPCResult::Type::STR_HEX, "hex", "The hex-encoded raw transaction with signature(s)"},
                         {RPCResult::Type::BOOL, "complete", "If the transaction has a complete set of signatures"},
-                        {RPCResult::Type::ARR, "errors", "Script verification errors (if there are any)",
+                        {RPCResult::Type::ARR, "errors", /* optional */ true, "Script verification errors (if there are any)",
                         {
                             {RPCResult::Type::OBJ, "", "",
                             {
@@ -1722,7 +1722,7 @@ UniValue analyzepsbt(const JSONRPCRequest& request)
                     {RPCResult::Type::STR_AMOUNT, "estimated_feerate", /* optional */ true, "Estimated feerate of the final signed transaction in " + CURRENCY_UNIT + "/kB. Shown only if all UTXO slots in the PSBT have been filled"},
                     {RPCResult::Type::STR_AMOUNT, "fee", /* optional */ true, "The transaction fee paid. Shown only if all UTXO slots in the PSBT have been filled"},
                     {RPCResult::Type::STR, "next", "Role of the next person that this psbt needs to go to"},
-                    {RPCResult::Type::STR, "error", "Error message if there is one"},
+                    {RPCResult::Type::STR, "error", /* optional */ true, "Error message (if there is one)"},
                 }
             },
             RPCExamples {