rpc: decode Miniscript descriptor when possible in decodescript

The descriptor inference logic would previously always use a dummy
signing provider and would never analyze the witness script of a P2WSH
scriptPubKey.

Note even a valid Miniscript might not always be decodable from Script
without more contextual information (for instance the key preimage for a
pk_h).

1 files changed, 3 insertions, 1 deletions

diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 7704496c10..503099d8a9 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -522,15 +522,17 @@ static RPCHelpMan decodescript()
         if (can_wrap_P2WSH) {
             UniValue sr(UniValue::VOBJ);
             CScript segwitScr;
+            FillableSigningProvider provider;
             if (which_type == TxoutType::PUBKEY) {
                 segwitScr = GetScriptForDestination(WitnessV0KeyHash(Hash160(solutions_data[0])));
             } else if (which_type == TxoutType::PUBKEYHASH) {
                 segwitScr = GetScriptForDestination(WitnessV0KeyHash(uint160{solutions_data[0]}));
             } else {
                 // Scripts that are not fit for P2WPKH are encoded as P2WSH.
+                provider.AddCScript(script);
                 segwitScr = GetScriptForDestination(WitnessV0ScriptHash(script));
             }
-            ScriptToUniv(segwitScr, /*out=*/sr, /*include_hex=*/true, /*include_address=*/true);
+            ScriptToUniv(segwitScr, /*out=*/sr, /*include_hex=*/true, /*include_address=*/true, /*provider=*/&provider);
             sr.pushKV("p2sh-segwit", EncodeDestination(ScriptHash(segwitScr)));
             r.pushKV("segwit", sr);
         }