Merge bitcoin/bitcoin#31468: test: Avoid intermittent error in assert_equal(pruneheight_new, 248)

fa0998f test: Avoid intermittent error in assert_equal(pruneheight_new, 248) (MarcoFalke)

Pull request description:

  Fixes bitcoin/bitcoin#31446

  The test uses the P2P network to sync blocks, which has no inherent guarantee that the blocks are sent and received in the right order, assuming the headers are received first.

  This can mean that the first block file is flushed with block at height 249 and block at height 248 is added to the second file. In the log it looks like: `Leaving block file 0: CBlockFileInfo(blocks=249, size=65319, heights=0...249, time=2011-02-02...2024-12-03) (onto 1) (height 248)`. The test assumes that the height of the last pruned block in the first file is 248, expecting it to look like: `Leaving block file 0: CBlockFileInfo(blocks=249, size=65319, heights=0...248, time=2011-02-02...2024-12-09) (onto 1) (height 249) `.

  Fix the issue by using a linear dumb sync.

ACKs for top commit:
  achow101:
    ACK fa0998f
  mzumsande:
    Code Review ACK fa0998f
  i-am-yuvi:
    Code Review ACK fa0998f
  fjahr:
    Code review ACK fa0998f

Tree-SHA512: 59cb4317be6cf9012c9bf7a3e9f5ba96b8b114b30bd2ac42af4fe742cd26a634d685b075f04a84bd782b2a43a342d75bb20a042bd82ad2831dbf844d39517ca2

Author: achow101

test/functional/feature_index_prune.py

@@ -1,8 +1,9 @@
 #!/usr/bin/env python3
-# Copyright (c) 2020-2022 The Bitcoin Core developers
+# Copyright (c) 2020-present The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test indices in conjunction with prune."""
+import concurrent.futures
 import os
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
@@ -19,9 +20,25 @@ def set_test_params(self):
             ["-fastprune", "-prune=1", "-blockfilterindex=1"],
             ["-fastprune", "-prune=1", "-coinstatsindex=1"],
             ["-fastprune", "-prune=1", "-blockfilterindex=1", "-coinstatsindex=1"],
-            []
+            [],
         ]
 
+    def setup_network(self):
+        self.setup_nodes()  # No P2P connection, so that linear_sync works
+
+    def linear_sync(self, node_from, *, height_from=None):
+        # Linear sync over RPC, because P2P sync may not be linear
+        to_height = node_from.getblockcount()
+        if height_from is None:
+            height_from = min([n.getblockcount() for n in self.nodes]) + 1
+        with concurrent.futures.ThreadPoolExecutor(max_workers=self.num_nodes) as rpc_threads:
+            for i in range(height_from, to_height + 1):
+                b = node_from.getblock(blockhash=node_from.getblockhash(i), verbosity=0)
+                list(rpc_threads.map(lambda n: n.submitblock(b), self.nodes))
+
+    def generate(self, node, num_blocks, sync_fun=None):
+        return super().generate(node, num_blocks, sync_fun=sync_fun or (lambda: self.linear_sync(node)))
+
     def sync_index(self, height):
         expected_filter = {
             'basic block filter index': {'synced': True, 'best_block_height': height},
@@ -36,22 +53,9 @@ def sync_index(self, height):
         expected = {**expected_filter, **expected_stats}
         self.wait_until(lambda: self.nodes[2].getindexinfo() == expected)
 
-    def reconnect_nodes(self):
-        self.connect_nodes(0,1)
-        self.connect_nodes(0,2)
-        self.connect_nodes(0,3)
-
-    def mine_batches(self, blocks):
-        n = blocks // 250
-        for _ in range(n):
-            self.generate(self.nodes[0], 250)
-        self.generate(self.nodes[0], blocks % 250)
-        self.sync_blocks()
-
     def restart_without_indices(self):
         for i in range(3):
             self.restart_node(i, extra_args=["-fastprune", "-prune=1"])
-        self.reconnect_nodes()
 
     def run_test(self):
         filter_nodes = [self.nodes[0], self.nodes[2]]
@@ -65,7 +69,7 @@ def run_test(self):
         for node in stats_nodes:
             assert node.gettxoutsetinfo(hash_type="muhash", hash_or_height=tip)['muhash']
 
-        self.mine_batches(500)
+        self.generate(self.nodes[0], 500)
         self.sync_index(height=700)
 
         self.log.info("prune some blocks")
@@ -104,7 +108,7 @@ def run_test(self):
             msg = "Querying specific block heights requires coinstatsindex"
             assert_raises_rpc_error(-8, msg, node.gettxoutsetinfo, "muhash", height_hash)
 
-        self.mine_batches(749)
+        self.generate(self.nodes[0], 749)
 
         self.log.info("prune exactly up to the indices best blocks while the indices are disabled")
         for i in range(3):
@@ -118,7 +122,7 @@ def run_test(self):
 
         self.log.info("prune further than the indices best blocks while the indices are disabled")
         self.restart_without_indices()
-        self.mine_batches(1000)
+        self.generate(self.nodes[0], 1000)
 
         for i in range(3):
             pruneheight_3 = self.nodes[i].pruneblockchain(2000)
@@ -134,12 +138,10 @@ def run_test(self):
 
         self.log.info("make sure the nodes start again with the indices and an additional -reindex arg")
         for i in range(3):
-            restart_args = self.extra_args[i]+["-reindex"]
+            restart_args = self.extra_args[i] + ["-reindex"]
             self.restart_node(i, extra_args=restart_args)
-            # The nodes need to be reconnected to the non-pruning node upon restart, otherwise they will be stuck
-            self.connect_nodes(i, 3)
 
-        self.sync_blocks(timeout=300)
+        self.linear_sync(self.nodes[3])
         self.sync_index(height=2500)
 
         for node in self.nodes[:2]:
@@ -150,8 +152,7 @@ def run_test(self):
         self.log.info("ensure that prune locks don't prevent indices from failing in a reorg scenario")
         with self.nodes[0].assert_debug_log(['basic block filter index prune lock moved back to 2480']):
             self.nodes[3].invalidateblock(self.nodes[0].getblockhash(2480))
-            self.generate(self.nodes[3], 30)
-            self.sync_blocks()
+            self.generate(self.nodes[3], 30, sync_fun=lambda: self.linear_sync(self.nodes[3], height_from=2480))
 
 
 if __name__ == '__main__':