fix(history): let the shielded scan complete + unstick send-progress on many-z-addr wallets

Two issues shared one root cause: the shielded-receive scan marked each z-address "scanned
at the EXACT current tip," but a new block (~36s on DRGX) advances the tip and invalidates
every prior per-address scan. A wallet with more z-addresses than one refresh cycle can
scan therefore never reached "all scanned at tip" — so shieldedScanComplete stayed false
and transactions_dirty_ stayed true forever, which (a) kept the history-refresh banner lit
and the full rescan churning every cycle, and (b) blocked maybeFinishTransactionSendProgress
(it waited on transactions_dirty_), leaving the send-progress indicator stuck on.

Fix 1 — completion tolerance. Add TransactionRefreshSnapshot::shieldedScanTipTolerance: an
address counts as fresh if its last scan is within N blocks of the tip (0 = old strict
behavior, so existing tests are unchanged). The app scales N with the z-address count
(2 + count/96, capped at 50), so a multi-block pass can COMPLETE before its earliest scan
goes stale. This also throttles full rescans to ~N blocks instead of every block —
transactions_dirty_ clears, the banner stops, and CPU/RPC churn drops. Already-fresh
addresses are skipped, so the per-block cost falls back to just the (cheap) transparent
listtransactions.

Fix 2 — send-progress gate. maybeFinishTransactionSendProgress() no longer waits on the
transaction history scan (transactions_dirty_ / Transactions job): the sent tx is already
shown via the optimistic pending insert, and the spend is reflected once the balance
refresh lands, so it now finishes on the address/balance signal alone.

Test: a tolerant snapshot skips recently-scanned addresses (shieldedAddressesScanned == 0,
shieldedScanComplete) while a strict one re-scans them.

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

src/app.cpp

@@ -3664,9 +3664,11 @@ void App::maybeFinishTransactionSendProgress()
     using Job = services::NetworkRefreshService::Job;
     if (!send_progress_active_) return;
     if (send_submissions_in_flight_ > 0 || !pending_opids_.empty()) return;
-    if (addresses_dirty_ || transactions_dirty_) return;
-    if (network_refresh_.jobInProgress(Job::Addresses) ||
-        network_refresh_.jobInProgress(Job::Transactions)) return;
+    // Finish once the spend is reflected in the balance (addresses). Do NOT wait on the transaction
+    // history scan: the sent tx is already shown via the optimistic pending insert, and the shielded
+    // history scan can stay "dirty" for a long time on wallets with many z-addresses — gating on it
+    // left the send-progress indicator stuck on indefinitely.
+    if (addresses_dirty_ || network_refresh_.jobInProgress(Job::Addresses)) return;
     send_progress_active_ = false;
 }
 void App::restartDaemon()

src/app_network.cpp

@@ -122,6 +122,19 @@ std::size_t shieldedReceiveScanBudget(ui::NavPage page)
     return page == ui::NavPage::History ? 8u : 4u;
 }
 
+// How far the tip may drift past an address's last shielded scan before we re-scan it. A full pass
+// scans ~budget addresses per refresh cycle (≈96 per block of wall time), so a wallet with many
+// z-addresses takes several blocks to scan fully. With a strict (tolerance 0) "scanned at tip"
+// check, new blocks arriving mid-pass would invalidate already-scanned addresses and the pass would
+// never complete — leaving transactions_dirty_ (and its "refreshing history" banner + send-progress
+// gate) stuck on forever. Scaling the tolerance with the address count lets the pass complete while
+// keeping shielded-receive latency minimal for small wallets; it's capped for pathological sizes.
+int shieldedScanTipTolerance(std::size_t shieldedAddressCount)
+{
+    int t = 2 + static_cast<int>(shieldedAddressCount / 96);
+    return std::min(t, 50);
+}
+
 } // namespace
 
 // ============================================================================
@@ -1297,6 +1310,8 @@ void App::refreshTransactionData()
     transactionSnapshot.shieldedScanHeights = shielded_history_scan_heights_;
     transactionSnapshot.shieldedScanStartIndex = shielded_history_scan_cursor_;
     transactionSnapshot.maxShieldedReceiveScans = shieldedReceiveScanBudget(current_page_);
+    transactionSnapshot.shieldedScanTipTolerance =
+        shieldedScanTipTolerance(transactionSnapshot.shieldedAddresses.size());
     ui::NavPage tracePage = current_page_;
 
     auto enqueued = network_refresh_.enqueue(services::NetworkRefreshService::Job::Transactions, *worker_, [this, currentBlocks,
@@ -1345,6 +1360,8 @@ void App::refreshRecentTransactionData()
     transactionSnapshot.shieldedScanHeights = shielded_history_scan_heights_;
     transactionSnapshot.shieldedScanStartIndex = shielded_history_scan_cursor_;
     transactionSnapshot.maxShieldedReceiveScans = 1;
+    transactionSnapshot.shieldedScanTipTolerance =
+        shieldedScanTipTolerance(transactionSnapshot.shieldedAddresses.size());
     ui::NavPage tracePage = current_page_;
 
     auto enqueued = network_refresh_.enqueue(services::NetworkRefreshService::Job::Transactions, *worker_, [this, currentBlocks,

src/services/network_refresh_service.cpp

@@ -822,10 +822,14 @@ NetworkRefreshService::TransactionRefreshResult NetworkRefreshService::collectTr
         DEBUG_LOGF("listtransactions error: %s\n", e.what());
     }
 
+    // An address counts as "scanned at tip" if its last scan is within shieldedScanTipTolerance
+    // blocks of the current tip. Tolerance 0 means strict (exact tip); a small tolerance lets a
+    // multi-cycle pass over many addresses complete even as the tip advances during it.
+    const int scanStaleThreshold = currentBlockHeight - std::max(0, snapshot.shieldedScanTipTolerance);
     auto scannedAtTip = [&](const std::string& address) {
         if (currentBlockHeight < 0) return false;
         auto it = result.shieldedScanHeights.find(address);
-        return it != result.shieldedScanHeights.end() && it->second >= currentBlockHeight;
+        return it != result.shieldedScanHeights.end() && it->second >= scanStaleThreshold;
     };
 
     std::size_t shieldedStart = snapshot.shieldedScanStartIndex;

src/services/network_refresh_service.h

@@ -178,6 +178,13 @@ public:
         std::unordered_map<std::string, int> shieldedScanHeights;
         std::size_t shieldedScanStartIndex = 0;
         std::size_t maxShieldedReceiveScans = 0;
+        // How many blocks the tip may advance past an address's last scan before it counts as stale
+        // and needs re-scanning. 0 = strict (must be scanned at the exact current tip). A small
+        // tolerance lets a multi-cycle pass over many shielded addresses COMPLETE even though new
+        // blocks arrive mid-pass — otherwise the "scanned at tip" bar moves every block and the scan
+        // (and the transactions_dirty_ flag it drives) never finishes. It also naturally throttles
+        // full rescans to roughly once per `tolerance` blocks.
+        int shieldedScanTipTolerance = 0;
     };
 
     struct TransactionRefreshResult {

tests/test_phase4.cpp

@@ -1477,6 +1477,36 @@ void testNetworkRefreshRpcCollectors()
     EXPECT_EQ(pagedResult.transactions.size(), static_cast<size_t>(1001));
     EXPECT_EQ(pagedResult.transactions[0].txid, std::string("paged-1000"));
 
+    // shieldedScanTipTolerance: an address scanned a few blocks below the tip is re-scanned when
+    // strict (tolerance 0) but SKIPPED within tolerance — this is what lets a multi-block pass
+    // complete (and unsticks the perpetual "refreshing history" state).
+    {
+        Refresh::TransactionRefreshSnapshot strictSnapshot;
+        strictSnapshot.shieldedAddresses = {"zs-a", "zs-b"};
+        strictSnapshot.shieldedScanHeights = {{"zs-a", 100}, {"zs-b", 100}};
+        strictSnapshot.maxShieldedReceiveScans = 4;
+        strictSnapshot.shieldedScanTipTolerance = 0;  // strict: heights 100 are stale at tip 102
+        MockRefreshRpc strictRpc;
+        strictRpc.addResponse("listtransactions", json::array());
+        strictRpc.addResponse("z_listreceivedbyaddress", json::array());
+        strictRpc.addResponse("z_listreceivedbyaddress", json::array());
+        auto strictResult = Refresh::collectTransactionRefreshResult(strictRpc, strictSnapshot, 102, 4);
+        EXPECT_EQ(strictResult.shieldedAddressesScanned, static_cast<size_t>(2));  // both re-scanned
+
+        Refresh::TransactionRefreshSnapshot tolerantSnapshot;
+        tolerantSnapshot.shieldedAddresses = {"zs-a", "zs-b"};
+        tolerantSnapshot.shieldedScanHeights = {{"zs-a", 100}, {"zs-b", 100}};
+        tolerantSnapshot.maxShieldedReceiveScans = 4;
+        tolerantSnapshot.shieldedScanTipTolerance = 5;  // 100 >= 102-5 -> still fresh
+        MockRefreshRpc tolerantRpc;
+        tolerantRpc.addResponse("listtransactions", json::array());
+        // No z_listreceivedbyaddress responses: the addresses must be skipped (else call() throws).
+        auto tolerantResult = Refresh::collectTransactionRefreshResult(tolerantRpc, tolerantSnapshot, 102, 4);
+        EXPECT_EQ(tolerantResult.shieldedAddressesScanned, static_cast<size_t>(0));  // both skipped
+        EXPECT_TRUE(tolerantResult.shieldedScanComplete);
+        EXPECT_TRUE(tolerantRpc.methodNames() == std::vector<std::string>({"listtransactions"}));
+    }
+
     Refresh::TransactionRefreshSnapshot recentSnapshot;
     dragonx::TransactionInfo previousShielded;
     previousShielded.txid = "shielded-old";