rpc: Include assumeutxo as a failure reason of rescanblockchain

Author: fjahr

src/wallet/rpc/transactions.cpp

@@ -6,6 +6,7 @@
 #include <key_io.h>
 #include <policy/rbf.h>
 #include <rpc/util.h>
+#include <rpc/blockchain.h>
 #include <util/vector.h>
 #include <wallet/receive.h>
 #include <wallet/rpc/util.h>
@@ -909,9 +910,15 @@ RPCHelpMan rescanblockchain()
             }
         }
 
-        // We can't rescan beyond non-pruned blocks, stop and throw an error
+        // We can't rescan unavailable blocks, stop and throw an error
         if (!pwallet->chain().hasBlocks(pwallet->GetLastBlockHash(), start_height, stop_height)) {
-            throw JSONRPCError(RPC_MISC_ERROR, "Can't rescan beyond pruned data. Use RPC call getblockchaininfo to determine your pruned height.");
+            if (pwallet->chain().havePruned() && pwallet->chain().getPruneHeight() >= start_height) {
+                throw JSONRPCError(RPC_MISC_ERROR, "Can't rescan beyond pruned data. Use RPC call getblockchaininfo to determine your pruned height.");
+            }
+            if (pwallet->chain().hasAssumedValidChain()) {
+                throw JSONRPCError(RPC_MISC_ERROR, "Failed to rescan unavailable blocks likely due to an in-progress assumeutxo background sync. Check logs or getchainstates RPC for assumeutxo background sync progress and try again later.");
+            }
+            throw JSONRPCError(RPC_MISC_ERROR, "Failed to rescan unavailable blocks, potentially caused by data corruption. If the issue persists you may want to reindex (see -reindex option).");
         }
 
         CHECK_NONFATAL(pwallet->chain().findAncestorByHeight(pwallet->GetLastBlockHash(), start_height, FoundBlock().hash(start_block)));

test/functional/wallet_assumeutxo.py

@@ -176,6 +176,10 @@ def run_test(self):
         assert_equal(result[0]['error']['code'], -1)
         assert_equal(result[0]['error']['message'], expected_error_message)
 
+        self.log.info("Test that rescanning blocks from before the snapshot fails when blocks are not available from the background sync yet")
+        w1 = n1.get_wallet_rpc(wallet_name)
+        assert_raises_rpc_error(-1, "Failed to rescan unavailable blocks likely due to an in-progress assumeutxo background sync. Check logs or getchainstates RPC for assumeutxo background sync progress and try again later.", w1.rescanblockchain, 100)
+
         PAUSE_HEIGHT = FINAL_HEIGHT - 40
 
         self.log.info("Restarting node to stop at height %d", PAUSE_HEIGHT)