fix(litebe): make HD t-address derivation atomic under scan

Deriving the next HD transparent address read the key count under a
read lock, released it, derived the address, and only then took a
write lock to append it. Between reading the position and appending,
another caller - for instance a scan deriving an address at the same
time - could read the same position, derive the same address, and
append it too, leaving a duplicate transparent key in the wallet.

- The whole read-modify-write now runs under a single write guard, so
  the position a caller derives from reflects every key already
  added. The slow seed stretch is computed once before the guard is
  taken, so holding the lock does not block on it.
- As a further guard, derivation skips a position whose address is
  already present and advances to the next, so no path can produce a
  duplicate even if positions were ever to overlap.
- The starting index is computed exactly as before (it still counts
  imported keys too), so a wallet with no contention derives the same
  addresses in the same order.

Uncontended derivation produces the same addresses in the same order,
verified against the differential harness. The wallet file format is
unchanged.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app.cpp

@@ -2163,10 +2163,10 @@ void App::render()
     // long confirmed (the other leg holds the real count). So: a txid with ANY confirmed leg is
     // confirmed, and we count UNIQUE unconfirmed txids — otherwise the badge sticks on stale 0-conf
     // legs of already-confirmed transactions and double-counts multi-leg ones.
-    // Recompute only when the tx list actually changed (last_tx_update is bumped on every tx refresh;
-    // size() catches same-second content changes). Otherwise this built two unordered_sets over the whole
+    // Recompute only when the tx list actually changed. tx_revision moves on EVERY content change (incl. a
+    // confirmation flip at equal tx count) and, unlike last_tx_update, lite stamps it. Otherwise this built two unordered_sets over the whole
     // wallet tx list every frame just to size a badge.
-    if (state_.last_tx_update != sb_unconf_key_ts_ || state_.transactions.size() != sb_unconf_key_n_) {
+    if (state_.tx_revision != sb_unconf_key_rev_) {
         std::unordered_set<std::string> confirmedTxids;
         for (const auto& tx : state_.transactions) {
             if (tx.confirmations >= 1) confirmedTxids.insert(tx.txid);
@@ -2178,8 +2178,7 @@ void App::render()
             }
         }
         sb_unconf_count_  = static_cast<int>(unconfirmedTxids.size());
-        sb_unconf_key_ts_ = state_.last_tx_update;
-        sb_unconf_key_n_  = state_.transactions.size();
+        sb_unconf_key_rev_ = state_.tx_revision;
     }
     sbStatus.unconfirmedTxCount = sb_unconf_count_;
 
@@ -7743,6 +7742,9 @@ void App::shutdown()
     // Lite: let an in-flight wallet op (e.g. Encrypt's save) finish. Bounded: the window is already hidden and
     // main.cpp has a 15 s watchdog. The backend writes tmp + rename, so being cut off never corrupts the wallet.
     if (lite_wallet_) lite_wallet_->waitWalletOpsIdle(std::chrono::milliseconds(2500));
+    // Persist refresh-scanned state: ~LiteWalletController never runs on the _Exit path. Bounded (4 s) so the
+    // 15 s watchdog budget holds; the save is tmp + rename, so an abandoned/cut-off save never corrupts.
+    if (lite_wallet_) lite_wallet_->flushOnExit(std::chrono::milliseconds(4000));
 
     // Full node: persist whatever a refresh changed since beginShutdown() (everything, on the direct-exit path),
     // then drain + join the history writer. Bounded like the settings flush: on a wedged disk the in-flight write

src/app.h

@@ -1006,10 +1006,9 @@ private:
     mutable std::uint64_t chat_unread_rev_ = ~0ull;   // ~0 forces the first compute
     mutable int    chat_unread_cached_ = 0;
     mutable double chat_unread_computed_at_ = 0.0;
-    // Sidebar unconfirmed-tx badge — recomputed only when the tx list changes (keyed on last_tx_update +
-    // size), not every frame. See App::render().
-    std::int64_t sb_unconf_key_ts_ = -1;
-    std::size_t  sb_unconf_key_n_  = 0;
+    // Sidebar unconfirmed-tx badge — recomputed only when the tx list changes (keyed on tx_revision),
+    // not every frame. See App::render().
+    std::uint64_t sb_unconf_key_rev_ = 0;   // sentinel 0 never matches: tx_revision starts at 1
     int          sb_unconf_count_  = 0;
     // Daemon-memory probe is expensive (/proc scan on Linux, popen on macOS): it runs on this sampler's own
     // thread, at most once per 3 s and only while a reader asks (Mining tab memory bar, Peers tab Memory cell).

src/rpc/rpc_client.cpp

@@ -451,8 +451,8 @@ json RPCClient::parseRpcResult(long httpCode, const std::string& body, bool scru
         throw RpcError(errCode, "RPC error: " + err_msg, httpCode);
     }
 
-    json result = response["result"];   // a COPY of the subobject (operator[] yields an lvalue ref)
-    if (scrubSource) scrubJsonSecrets(response);  // zero the discarded tree's secret before it frees (B7)
+    json result = std::move(response["result"]);  // move the subtree out: the secret now lives only here
+    if (scrubSource) scrubJsonSecrets(response);   // response["result"] is now moved-from (null); harmless (B7)
     return result;
 }
 
@@ -684,7 +684,7 @@ void RPCClient::z_getNewAddress(Callback cb, ErrorCallback err)
 
 void RPCClient::listTransactions(int count, Callback cb, ErrorCallback err)
 {
-    doRPC("listtransactions", {"", count}, cb, err);
+    doRPC("listtransactions", {"*", count}, cb, err);
 }
 
 void RPCClient::z_viewTransaction(const std::string& txid, Callback cb, ErrorCallback err)

src/rpc/rpc_client.h

@@ -285,9 +285,9 @@ private:
     // hold curl_mutex_ and have verified impl_->curl.
     std::string performCall(const std::string& method, const json& params, long& httpCodeOut);
     // Centralizes the HTTP-code check and JSON error->RpcError extraction, returning
-    // response["result"] on success. When scrubSource is true (secret-bearing calls), the intermediate
-    // parse tree's string values are zeroed before it is discarded — parseRpcResult returns a COPY of
-    // the result node, so its own tree would otherwise free the secret un-wiped (B7).
+    // response["result"] on success. The result subtree is moved out of the parse tree, so a secret lives
+    // only in the returned node (which callSecret/callSecretString callers wipe). When scrubSource is true
+    // (secret-bearing calls), any remaining parse-tree string values are zeroed before it is discarded (B7).
     static json parseRpcResult(long httpCode, const std::string& body, bool scrubSource = false);
     // A non-200 reply: RpcError when the body carries a JSON-RPC error, else RpcTransportError classified
     // from the status and plain-text body. hideBody keeps the body out of the message (secret calls).

src/services/network_refresh_service.cpp

@@ -12,6 +12,7 @@
 #include <map>
 #include <set>
 #include <unordered_map>
+#include <unordered_set>
 
 using json = nlohmann::json;
 
@@ -932,6 +933,9 @@ void NetworkRefreshService::appendTransparentTransactions(std::vector<Transactio
     for (const auto& transactionJson : result) {
         TransactionInfo info;
         if (auto value = readOptional<std::string>(transactionJson, "txid")) info.txid = *value;
+        // C266: listtransactions("*") also returns "move" accounting rows (no txid/address/vout) for
+        // every account. They are not wallet transactions - skip so they never become blank History rows.
+        if (info.txid.empty()) continue;
         if (auto value = readOptional<std::string>(transactionJson, "category")) info.type = *value;
         if (auto value = readOptional<double>(transactionJson, "amount")) info.amount = *value;
         if (auto value = readOptional<std::int64_t>(transactionJson, "time")) {
@@ -1169,11 +1173,33 @@ NetworkRefreshService::TransactionRefreshResult NetworkRefreshService::collectTr
             // The first page holds last time's count plus headroom, so most wallets get every row in one
             // call (re-paging 1000 rows at a time formats ~rows^2/2000 rows); skip-paging stays the fallback.
             const int pageSize = transparentPageSize(snapshot.transparentRowHint);
+            std::unordered_set<std::string> seenPagedRows;
             for (int skip = 0;; skip += pageSize) {
-                json page = rpc.call("listtransactions", json::array({"", pageSize, skip}));
-                appendTransparentTransactions(result.transactions, knownTxids, page, snapshot.miningAddresses);
+                json page = rpc.call("listtransactions", json::array({"*", pageSize, skip}));
                 const std::size_t got = page.is_array() ? page.size() : 0;
-                result.transparentRowCount += got;
+                // C267: skip-paging walks a list that can shift between RPCs (a new tx pushes the
+                // previous page's tail into this page's head). De-dup on the daemon's stable per-output
+                // identity (txid, send/non-send class, vout). Key on the send/non-send CLASS, not the
+                // exact category, so a coinbase maturing (immature->generate) between the two fetches is
+                // still recognised as the same row; keep vout so two equal-value outputs of one tx stay
+                // distinct. Rows without txid or vout ("move") are never keyed and pass through
+                // (appendTransparentTransactions drops them anyway).
+                json uniq = json::array();
+                if (page.is_array()) {
+                    for (const auto& row : page) {
+                        auto txid = readOptional<std::string>(row, "txid");
+                        auto vout = readOptional<int>(row, "vout");
+                        if (txid && !txid->empty() && vout) {
+                            const bool isSend =
+                                readOptional<std::string>(row, "category").value_or("") == "send";
+                            std::string key = *txid + '|' + (isSend ? 's' : 'r') + '|' + std::to_string(*vout);
+                            if (!seenPagedRows.insert(std::move(key)).second) continue;  // true duplicate
+                        }
+                        uniq.push_back(row);
+                    }
+                }
+                appendTransparentTransactions(result.transactions, knownTxids, uniq, snapshot.miningAddresses);
+                result.transparentRowCount += got;   // RAW page size: drives the stop test + next row hint
                 if (got < static_cast<std::size_t>(pageSize)) break;
             }
             result.transparentChainOk = true;
@@ -1555,7 +1581,7 @@ NetworkRefreshService::TransactionRefreshResult NetworkRefreshService::collectRe
     try {
         std::set<std::string> recentTxids;
         std::vector<TransactionInfo> recentTransactions;
-        json transactions = rpc.call("listtransactions", json::array({"", pageSize, 0}));
+        json transactions = rpc.call("listtransactions", json::array({"*", pageSize, 0}));
         appendTransparentTransactions(recentTransactions, recentTxids, transactions, snapshot.miningAddresses);
 
         // A coinbase changes category in place (immature -> generate at maturity, or -> orphan on a reorg): drop

src/wallet/lite_wallet_controller.cpp

@@ -11,7 +11,11 @@
 
 #include <algorithm>
 #include <chrono>
+#include <condition_variable>
 #include <cstdint>
+#include <memory>
+#include <mutex>
+#include <thread>
 #include <unordered_map>
 #include <utility>
 
@@ -499,6 +503,27 @@ LiteWalletController::LiteWalletController(WalletCapabilities capabilities,
     status_ = lifecycle_.status();
 }
 
+void LiteWalletController::flushOnExit(std::chrono::milliseconds budget)
+{
+    // Same guards as the destructor, plus walletOpInProgress(): App::shutdown() already ran
+    // waitWalletOpsIdle(); if an op is still pending it holds sync_lock and issues its own save,
+    // so skip rather than block the budget on a save that cannot acquire the lock.
+    if (retired_.load() || !walletOpen_.load() || !syncComplete() ||
+        broadcastInProgress() || walletOpInProgress() || !bridge_) return;
+    struct Done { std::mutex m; std::condition_variable cv; bool done = false; };
+    auto st = std::make_shared<Done>();
+    auto bridge = bridge_;                               // shared_ptr copy; never captures `this`
+    try {
+        std::thread([bridge, st]() {
+            bridge->execute("save", "");                 // may block on sync_lock; abandoned on timeout
+            { std::lock_guard<std::mutex> l(st->m); st->done = true; }
+            st->cv.notify_all();
+        }).detach();
+    } catch (...) { return; }                            // no thread: skip (pre-fix behaviour, no crash)
+    std::unique_lock<std::mutex> l(st->m);
+    st->cv.wait_for(l, budget, [&] { return st->done; });  // timeout: abandon the thread; _Exit follows
+}
+
 LiteWalletController::~LiteWalletController()
 {
     scan_->cancel.store(true);   // the detached sync thread stops retrying (it may be in a back-off sleep)
@@ -515,7 +540,8 @@ LiteWalletController::~LiteWalletController()
     }
     // The sync thread may be blocked in an uninterruptible full scan; detach it. It holds
     // shared refs (bridge_ + syncDone_), so it stays safe and the bridge survives until it
-    // finishes — the process is exiting, so a late litelib_shutdown is harmless.
+    // finishes — on the quit path the process is exiting, so a late litelib_shutdown is harmless
+    // (a server switch already shut the bridge down in retire()).
     if (syncThread_.joinable()) syncThread_.detach();
     // Likewise the broadcast thread (send/shield proving): it captures shared refs (bridge +
     // running flag + result slot), never `this`, so detaching is safe.

src/wallet/lite_wallet_controller.h

@@ -175,6 +175,10 @@ public:
 
     ~LiteWalletController();  // stops + joins the background refresh worker
 
+    // Best-effort persist on the quit path (the destructor's save is skipped because main() _Exit()s).
+    // Bounded: abandons the save thread on timeout; the process is about to _Exit. Same guards as ~dtor.
+    void flushOnExit(std::chrono::milliseconds budget);
+
     LiteWalletController(const LiteWalletController&) = delete;
     LiteWalletController& operator=(const LiteWalletController&) = delete;
 

tests/test_phase4.cpp

@@ -1684,6 +1684,20 @@ void testNetworkRefreshSnapshotHelpers()
     EXPECT_EQ(transactions[0].timestamp, static_cast<int64_t>(100));
     EXPECT_EQ(transactions[1].timestamp, static_cast<int64_t>(300));
 
+    {
+        // C266: "move" accounting rows (no txid) are skipped; labelled-address receive rows are kept.
+        std::vector<dragonx::TransactionInfo> moveTx;
+        std::set<std::string> moveKnown;
+        Refresh::appendTransparentTransactions(moveTx, moveKnown, json::array({
+            json{{"category", "move"}, {"account", "x"}, {"amount", 0.5}, {"time", 50}},
+            json{{"txid", "labelled-recv"}, {"category", "receive"}, {"account", "savings"},
+                 {"amount", 2.0}, {"time", 60}, {"confirmations", 3}, {"address", "R-labelled"}}
+        }));
+        EXPECT_EQ(moveTx.size(), static_cast<size_t>(1));
+        EXPECT_EQ(moveTx[0].txid, std::string("labelled-recv"));
+        EXPECT_EQ(moveKnown.count(""), static_cast<size_t>(0));
+    }
+
     Refresh::appendShieldedReceivedTransactions(transactions, knownTxids, "zs-viewonly", json::array({
         json{{"txid", "transparent-a"}, {"amount", 9.0}, {"confirmations", 1}},
         json{{"txid", "shielded-change"}, {"change", true}, {"amount", 2.0}},
@@ -2411,11 +2425,41 @@ void testNetworkRefreshRpcCollectors()
     }));
     auto pagedResult = Refresh::collectTransactionRefreshResult(pagedRpc, pagedSnapshot, 327, 0);
     EXPECT_TRUE(pagedRpc.methodNames() == std::vector<std::string>({"listtransactions", "listtransactions"}));
-    EXPECT_EQ(pagedRpc.calls[0].params, json::array({"", 1000, 0}));
-    EXPECT_EQ(pagedRpc.calls[1].params, json::array({"", 1000, 1000}));
+    EXPECT_EQ(pagedRpc.calls[0].params, json::array({"*", 1000, 0}));
+    EXPECT_EQ(pagedRpc.calls[1].params, json::array({"*", 1000, 1000}));
     EXPECT_EQ(pagedResult.transactions.size(), static_cast<size_t>(1001));
     EXPECT_EQ(pagedResult.transactions[0].txid, std::string("paged-1000"));
 
+    {
+        // C267: a tx added between page RPCs shifts the list, so the previous page's last row reappears at
+        // the head of the next page. Rows (txid, send/non-send, vout) already taken are dropped; a sibling
+        // output of the same tx (different vout) and an un-keyable row (no vout) are kept (fail-open).
+        Refresh::TransactionRefreshSnapshot dedupSnapshot;
+        MockRefreshRpc dedupRpc;
+        json page1 = json::array();
+        for (int i = 0; i < 1000; ++i) {
+            page1.push_back(json{{"txid", "dd-" + std::to_string(i)}, {"vout", 0}, {"category", "receive"},
+                                  {"amount", 0.01}, {"time", i}, {"confirmations", 10},
+                                  {"address", "R-dd"}});
+        }
+        dedupRpc.addResponse("listtransactions", page1);
+        dedupRpc.addResponse("listtransactions", json::array({
+            json{{"txid", "dd-999"}, {"vout", 0}, {"category", "receive"}, {"amount", 0.01},
+                 {"time", 999}, {"confirmations", 10}, {"address", "R-dd"}},          // repeat: dropped
+            json{{"txid", "dd-999"}, {"vout", 1}, {"category", "receive"}, {"amount", 0.01},
+                 {"time", 999}, {"confirmations", 10}, {"address", "R-dd"}},          // sibling vout: kept
+            json{{"txid", "dd-novout"}, {"category", "receive"}, {"amount", 0.02},
+                 {"time", 1001}, {"confirmations", 9}, {"address", "R-dd"}}           // no vout: kept
+        }));
+        auto dedupResult = Refresh::collectTransactionRefreshResult(dedupRpc, dedupSnapshot, 328, 0);
+        EXPECT_EQ(dedupRpc.calls.size(), static_cast<size_t>(2));
+        EXPECT_EQ(dedupResult.transactions.size(), static_cast<size_t>(1002));
+        EXPECT_EQ(dedupResult.transparentRowCount, static_cast<size_t>(1003));  // RAW count, not deduped
+        size_t dd999 = 0;
+        for (const auto& t : dedupResult.transactions) if (t.txid == "dd-999") ++dd999;
+        EXPECT_EQ(dd999, static_cast<size_t>(2));  // vout 0 once + vout 1
+    }
+
     // The pass floor: an address scanned below it is scanned again; without a floor (no pass running)
     // only never-scanned addresses are. A pass's floor is its start height, so it completes however far
     // the tip moves meanwhile (this is what unsticks the perpetual "refreshing history" state).
@@ -2469,7 +2513,7 @@ void testNetworkRefreshRpcCollectors()
     }));
     auto recent = Refresh::collectRecentTransactionRefreshResult(recentRpc, recentSnapshot, 123);
     EXPECT_TRUE(recentRpc.methodNames() == std::vector<std::string>({"listtransactions"}));
-    EXPECT_EQ(recentRpc.calls[0].params, json::array({"", 100, 0}));
+    EXPECT_EQ(recentRpc.calls[0].params, json::array({"*", 100, 0}));
     EXPECT_EQ(recent.blockHeight, 123);
     EXPECT_EQ(recent.transactions.size(), static_cast<size_t>(3));
     EXPECT_EQ(recent.transactions[0].txid, std::string("recent-two"));
@@ -10383,6 +10427,63 @@ void testLiteWalletControllerM5Persistence()
     }
 }
 
+// C30: flushOnExit() persists once on the quit path, is bounded when the save blocks, and obeys the guards.
+void testLiteWalletControllerFlushOnExit()
+{
+    using namespace dragonx::wallet;
+    const auto liteCaps = makeWalletCapabilities(WalletBuildKind::Lite, false, true);
+    const LiteConnectionSettings conn = defaultLiteConnectionSettings();
+    auto openSynced = [&]() {
+        dragonx::test::g_liteFakeSyncBlock = false;
+        auto c = std::make_unique<LiteWalletController>(
+            liteCaps, conn, LiteClientBridge::fromApi(dragonx::test::makeFakeLiteApi()));
+        LiteWalletCreateRequest req;
+        (void)c->createWallet(req);
+        for (int i = 0; i < 400 && !c->syncComplete(); ++i)
+            std::this_thread::sleep_for(std::chrono::milliseconds(5));
+        return c;
+    };
+
+    // (a) open + synced + idle -> exactly one save
+    {
+        auto c = openSynced();
+        EXPECT_TRUE(c->syncComplete());
+        const long before = dragonx::test::g_liteFakeSaveCount.load();
+        c->flushOnExit(std::chrono::milliseconds(500));
+        EXPECT_EQ(dragonx::test::g_liteFakeSaveCount.load(), before + 1);
+    }
+
+    // (b) a blocked save never hangs the caller past the budget
+    {
+        auto c = openSynced();
+        dragonx::test::g_liteFakeBlockSave = true;
+        const auto t0 = std::chrono::steady_clock::now();
+        c->flushOnExit(std::chrono::milliseconds(200));
+        const auto dt = std::chrono::steady_clock::now() - t0;
+        EXPECT_TRUE(dt >= std::chrono::milliseconds(150));
+        EXPECT_TRUE(dt < std::chrono::milliseconds(1500));
+        dragonx::test::g_liteFakeBlockSave = false;      // let the abandoned save thread finish
+        std::this_thread::sleep_for(std::chrono::milliseconds(150));
+    }
+
+    // (c) retired -> no save
+    {
+        auto c = openSynced();
+        c->retire("switch");
+        const long before = dragonx::test::g_liteFakeSaveCount.load();
+        c->flushOnExit(std::chrono::milliseconds(300));
+        EXPECT_EQ(dragonx::test::g_liteFakeSaveCount.load(), before);
+    }
+
+    // (d) wallet never opened -> no save
+    {
+        LiteWalletController c(liteCaps, conn, LiteClientBridge::fromApi(dragonx::test::makeFakeLiteApi()));
+        const long before = dragonx::test::g_liteFakeSaveCount.load();
+        c.flushOnExit(std::chrono::milliseconds(300));
+        EXPECT_EQ(dragonx::test::g_liteFakeSaveCount.load(), before);
+    }
+}
+
 // Encryption: the controller drives encrypt/unlock/lock/decrypt + encryptionstatus through the
 // (injected fake) backend, wipes passphrases, and folds status into WalletState (encrypted/locked).
 void testLiteWalletControllerEncryption()
@@ -16194,7 +16295,7 @@ void testHistoryCollectorSweepAndEnrichment()
         MockRefreshRpc rpc;
         rpc.addResponse("listtransactions", json::array());
         auto result = Refresh::collectTransactionRefreshResult(rpc, snap, 110, 4);
-        EXPECT_EQ(rpc.calls[0].params, json::array({"", 1700, 0}));
+        EXPECT_EQ(rpc.calls[0].params, json::array({"*", 1700, 0}));
         EXPECT_TRUE(result.transparentChainOk);
     }
     {   // Same tip, nothing changed: the transparent rows are reused, no listtransactions at all; a tracked
@@ -18868,6 +18969,7 @@ int main()
     testLiteRolloutPolicyStagedRollout();
     testLiteRolloutManifestLoader();
     testLiteWalletControllerRolloutGate();
+    testLiteWalletControllerFlushOnExit();
     testXmrigReleaseParsing();
     testXmrigAssetSelection();
     testXmrigChecksumParsing();

third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/grpcconnector.rs

@@ -11,7 +11,7 @@ use tokio_rustls::{rustls::ClientConfig};
 use tonic::{Request};
 
 use threadpool::ThreadPool;
-use std::sync::mpsc::channel;
+use std::sync::mpsc::{channel, sync_channel};
 
 use crate::PubCertificate;
 use crate::grpc_client::compact_tx_streamer_client::CompactTxStreamerClient;
@@ -113,7 +113,7 @@ where F : Fn(&[u8], u64) {
 
     let request = Request::new(BlockRange { start: Some(bs), end: Some(be) });
 
-    let (tx, rx) = channel::<Option<CompactBlock>>();
+    let (tx, rx) = sync_channel::<Option<CompactBlock>>(2048);
     let (ftx, frx) = channel();
 
     pool.execute(move || {

third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightclient.rs

@@ -908,7 +908,7 @@ impl LightClient {
 
             // Write to a temporary file first (atomic save). C254/s1-D9: a fresh owner-only file (0600 on unix); a stale
             // .dat.tmp is unlinked first, never reused. The rename carries the mode to the wallet.
-            let wallet = self.wallet.write().unwrap();
+            let wallet = self.wallet.read().unwrap();
             let mut file_buffer = BufWriter::with_capacity(
                 1_000_000, // 1 MB write buffer
                 create_private_file_new(&tmp_path).map_err(|e| format!("Failed to create temp file: {}", e))?);
@@ -1660,8 +1660,9 @@ pub fn start_mempool_monitor(lc: Arc<LightClient>) -> Result<(), String> {
         // get_block_range streams an ENTIRE range over ONE gRPC connection, so the batch size is
         // the dominant factor in how many TCP connections a sync opens. The old 1000 meant ~1300
         // connections for a full sync, which on Windows exhausted socket buffers (WSAENOBUFS / os
-        // error 10055). A large batch (25k) cuts that ~50x (~52 connections for a full sync) with
-        // no extra memory — blocks are still streamed + scanned incrementally, not buffered.
+        // error 10055). A large batch (25k) cuts that ~50x (~52 connections for a full sync). Blocks
+        // are now buffered up to 2048 deep (bounded backpressure, C240), still one connection per
+        // 25k batch; scan_batch_size must NOT shrink or Windows WSAENOBUFS returns.
         let scan_batch_size = 25000;
         let mut end_height = std::cmp::min(last_scanned_height + scan_batch_size, latest_block);
 
@@ -1805,7 +1806,7 @@ pub fn start_mempool_monitor(lc: Arc<LightClient>) -> Result<(), String> {
                 self.taddr_note_unscanned(start_height, &block_times);
                 // Reset the scanning heights
                 last_scanned_height = (invalid_height - 1) as u64;
-                end_height = std::cmp::min(last_scanned_height + scan_batch_size, latest_block);
+                end_height = std::cmp::min(last_scanned_height + crate::lightwallet::MAX_REORG as u64 + 1, latest_block);
 
                 warn!("Reorg: reset scanning from {} to {}", last_scanned_height, end_height);
 

third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightwallet.rs

@@ -659,15 +659,17 @@ impl LightWallet {
             return "Error: Can't add key while wallet is encrypted".to_string();
         }
 
-        let pos = self.tkeys.read().unwrap().len() as u32;
+        // PBKDF2 (the slow part) outside the lock; hold ONE write guard across read-modify-write.
         let bip39_seed = bip39::Seed::new(&Mnemonic::from_entropy(&self.seed, Language::English).unwrap(), "");
-        
-        let sk = LightWallet::get_taddr_from_bip39seed(&self.config, &bip39_seed.as_bytes(), pos);
-        let address = self.address_from_sk(&sk);
-
-        self.tkeys.write().unwrap().push(WalletTKey::new_hdkey(sk, address.clone()));
-
-        address
+        let mut tkeys = self.tkeys.write().unwrap();
+        let mut pos = tkeys.len() as u32; // same start index as today (counts imported keys too - unchanged)
+        loop {
+            let sk = LightWallet::get_taddr_from_bip39seed(&self.config, &bip39_seed.as_bytes(), pos);
+            let address = self.address_from_sk(&sk);
+            if tkeys.iter().any(|t| t.address == address) { pos += 1; continue; }
+            tkeys.push(WalletTKey::new_hdkey(sk, address.clone()));
+            return address;
+        }
     }
 
     pub fn import_taddr(&mut self, sk: String,  birthday: u64) -> String {

third_party/silentdragonxlite/silentdragonxlite-cli/lib/src/lightwallet/data.rs

@@ -1,5 +1,7 @@
 use std::io::{self, Read, Write};
 use std::sync::Arc;
+use std::cell::RefCell;
+use std::collections::HashMap;
 
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use pairing::bls12_381::{Bls12};
@@ -26,6 +28,24 @@ use zcash_primitives::{
 use zcash_primitives::zip32::ExtendedSpendingKey;
 
 
+// C241: wallet open re-parsed the 169-byte ExtendedFullViewingKey once PER NOTE. Memoize the decode,
+// keyed by the exact 169 raw bytes (content-addressed, so the result is always identical to a fresh
+// parse). Thread-local and naturally bounded by the handful of distinct keys a wallet holds.
+thread_local! {
+    static EFVK_CACHE: RefCell<HashMap<[u8; 169], ExtendedFullViewingKey>> = RefCell::new(HashMap::new());
+}
+
+fn read_efvk_cached<R: Read>(r: &mut R) -> io::Result<ExtendedFullViewingKey> {
+    let mut raw = [0u8; 169];
+    r.read_exact(&mut raw)?;
+    if let Some(k) = EFVK_CACHE.with(|c| c.borrow().get(&raw).cloned()) {
+        return Ok(k);
+    }
+    let k = ExtendedFullViewingKey::read(&raw[..])?; // identical parser on identical bytes
+    EFVK_CACHE.with(|c| c.borrow_mut().insert(raw, k.clone()));
+    Ok(k)
+}
+
 pub struct BlockData {
     pub height: i32,
     pub hash: BlockHash,
@@ -147,7 +167,7 @@ impl SaplingNoteData {
 
         let account = reader.read_u64::<LittleEndian>()? as usize;
 
-        let extfvk = ExtendedFullViewingKey::read(&mut reader)?;
+        let extfvk = read_efvk_cached(&mut reader)?;
 
         let mut diversifier_bytes = [0u8; 11];
         reader.read_exact(&mut diversifier_bytes)?;