Merge bitcoin/bitcoin#28067: descriptors: do not return top-level only funcs as sub descriptors

dd9633b516d6936ac4e23a40f9b0bea120117d35 test: wallet, add coverage for watch-only raw sh script migration (furszy)
cc781a21800a6ce13875feefd0cb14ab0a84524c descriptor: InferScript, do not return top-level only func as sub descriptor (furszy)
286e0c7d5e9538198b28b792c5168b8fafa1534f wallet: loading, log descriptor parsing error details (furszy)

Pull request description:

  Linked to #28057.

  Currently, the `InferScript` function returns an invalid descriptor when it tries to infer a p2sh-p2pkh script whose pubkey is not known by the wallet.

  This behavior occurs because the inference process bypasses the `pkh` subscript when the pubkey is not contained by the wallet (no pubkey provider), interpreting it as a `sh(addr(ADDR))` descriptor. Then, the failure arises because the `addr()` function is restricted to being used only at the top level.

  For reviewers, would recommend to start by examining the functional test to understand the context and the circumstances on which this can result in a fatal error (e.g. during the migration process).

ACKs for top commit:
  achow101:
    ACK dd9633b516d6936ac4e23a40f9b0bea120117d35
  darosior:
    utACK dd9633b516d6936ac4e23a40f9b0bea120117d35

Tree-SHA512: 61e763206c604c372019d2c36e31684f3dddf81f8b154eb9aba5cd66d8d61bda457ed4e591613eb6ce6c76cf7c3f11764abc6cd727a7c2b6414f1065783be032

1 files changed, 3 insertions, 1 deletions

diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index ffe5fd4a18..8212c04464 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -794,11 +794,13 @@ static DBErrors LoadDescriptorWalletRecords(CWallet* pwallet, DatabaseBatch& bat
         WalletDescriptor desc;
         try {
             value >> desc;
-        } catch (const std::ios_base::failure&) {
+        } catch (const std::ios_base::failure& e) {
             strErr = strprintf("Error: Unrecognized descriptor found in wallet %s. ", pwallet->GetName());
             strErr += (last_client > CLIENT_VERSION) ? "The wallet might had been created on a newer version. " :
                     "The database might be corrupted or the software version is not compatible with one of your wallet descriptors. ";
             strErr += "Please try running the latest software version";
+            // Also include error details
+            strErr = strprintf("%s\nDetails: %s", strErr, e.what());
             return DBErrors::UNKNOWN_DESCRIPTOR;
         }
         pwallet->LoadDescriptorScriptPubKeyMan(id, desc);