Merge bitcoin/bitcoin#28920: wallet: birth time update during tx scanning

1ce45baed7dd2da3f1cb85c9c25110e5537451ae rpc: getwalletinfo, return wallet 'birthtime' (furszy)
83c66444d0604f0a9ec3bc3f89d4f1a810b7cda0 test: coverage for wallet birth time interaction with -reindex (furszy)
6f497377aa17cb8a590fd7717fa8ededf4249999 wallet: fix legacy spkm default birth time (furszy)
75fbf444c1e13c6ba0e79a34871534c845a13849 wallet: birth time update during tx scanning (furszy)
b4306e3c8db6cbaedc8845c6d21c750b39f682bf refactor: rename FirstKeyTimeChanged to MaybeUpdateBirthTime (furszy)

Pull request description:

  Fixing #28897.

  As the user may have imported a descriptor with a timestamp newer
  than the actual birth time of the first key (by setting 'timestamp=now'),
  the wallet needs to update the birth time when it detects a transaction
  older than the oldest descriptor timestamp.

  Testing Notes:
  Can cherry-pick the test commit on top of master. It will fail there.

ACKs for top commit:
  Sjors:
    re-utACK 1ce45baed7dd2da3f1cb85c9c25110e5537451ae
  achow101:
    ACK 1ce45baed7dd2da3f1cb85c9c25110e5537451ae

Tree-SHA512: 10c2382f87356ae9ea3fcb637d7edc5ed0e51e13cc2729c314c9ffb57c684b9ac3c4b757b85810c0a674020b7287c43d3be8273bcf75e2aff0cc1c037f1159f9

1 files changed, 4 insertions, 0 deletions

diff --git a/src/wallet/rpc/wallet.cpp b/src/wallet/rpc/wallet.cpp
index 164ce9afed..c635093344 100644
--- a/src/wallet/rpc/wallet.cpp
+++ b/src/wallet/rpc/wallet.cpp
@@ -69,6 +69,7 @@ static RPCHelpMan getwalletinfo()
                         {RPCResult::Type::BOOL, "descriptors", "whether this wallet uses descriptors for scriptPubKey management"},
                         {RPCResult::Type::BOOL, "external_signer", "whether this wallet is configured to use an external signer such as a hardware wallet"},
                         {RPCResult::Type::BOOL, "blank", "Whether this wallet intentionally does not contain any keys, scripts, or descriptors"},
+                        {RPCResult::Type::NUM_TIME, "birthtime", /*optional=*/true, "The start time for blocks scanning. It could be modified by (re)importing any descriptor with an earlier timestamp."},
                         RESULT_LAST_PROCESSED_BLOCK,
                     }},
                 },
@@ -132,6 +133,9 @@ static RPCHelpMan getwalletinfo()
     obj.pushKV("descriptors", pwallet->IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));
     obj.pushKV("external_signer", pwallet->IsWalletFlagSet(WALLET_FLAG_EXTERNAL_SIGNER));
     obj.pushKV("blank", pwallet->IsWalletFlagSet(WALLET_FLAG_BLANK_WALLET));
+    if (int64_t birthtime = pwallet->GetBirthTime(); birthtime != UNKNOWN_TIME) {
+        obj.pushKV("birthtime", birthtime);
+    }
 
     AppendLastProcessedBlock(obj, *pwallet);
     return obj;