Figure out what is missing during signing

When signing an input, figure out what was requested for but was unable
to be found and store it in a SignatureData.

Return this information in SignPSBTInput.

2 files changed, 17 insertions, 2 deletions

diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index 9d6a390ea2..320956d0c4 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -83,6 +83,8 @@ static bool CreateSig(const BaseSignatureCreator& creator, SignatureData& sigdat
         assert(i.second);
         return true;
     }
+    // Could not make signature or signature not found, add keyid to missing
+    sigdata.missing_sigs.push_back(keyid);
     return false;
 }
 
@@ -116,17 +118,24 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
     case TX_PUBKEYHASH: {
         CKeyID keyID = CKeyID(uint160(vSolutions[0]));
         CPubKey pubkey;
-        if (!GetPubKey(provider, sigdata, keyID, pubkey)) return false;
+        if (!GetPubKey(provider, sigdata, keyID, pubkey)) {
+            // Pubkey could not be found, add to missing
+            sigdata.missing_pubkeys.push_back(keyID);
+            return false;
+        }
         if (!CreateSig(creator, sigdata, provider, sig, pubkey, scriptPubKey, sigversion)) return false;
         ret.push_back(std::move(sig));
         ret.push_back(ToByteVector(pubkey));
         return true;
     }
     case TX_SCRIPTHASH:
-        if (GetCScript(provider, sigdata, uint160(vSolutions[0]), scriptRet)) {
+        h160 = uint160(vSolutions[0]);
+        if (GetCScript(provider, sigdata, h160, scriptRet)) {
             ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
             return true;
         }
+        // Could not find redeemScript, add to missing
+        sigdata.missing_redeem_script = h160;
         return false;
 
     case TX_MULTISIG: {
@@ -154,6 +163,8 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
             ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
             return true;
         }
+        // Could not find witnessScript, add to missing
+        sigdata.missing_witness_script = uint256(vSolutions[0]);
         return false;
 
     default:
diff --git a/src/script/sign.h b/src/script/sign.h
index 64eb3eb8e5..e229c375c7 100644
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -117,6 +117,10 @@ struct SignatureData {
     CScriptWitness scriptWitness; ///< The scriptWitness of an input. Contains complete signatures or the traditional partial signatures format. scriptWitness is part of a transaction input per BIP 144.
     std::map<CKeyID, SigPair> signatures; ///< BIP 174 style partial signatures for the input. May contain all signatures necessary for producing a final scriptSig or scriptWitness.
     std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> misc_pubkeys;
+    std::vector<CKeyID> missing_pubkeys; ///< KeyIDs of pubkeys which could not be found
+    std::vector<CKeyID> missing_sigs; ///< KeyIDs of pubkeys for signatures which could not be found
+    uint160 missing_redeem_script; ///< ScriptID of the missing redeemScript (if any)
+    uint256 missing_witness_script; ///< SHA256 of the missing witnessScript (if any)
 
     SignatureData() {}
     explicit SignatureData(const CScript& script) : scriptSig(script) {}