Merge bitcoin/bitcoin#23046: test: Add txindex migration test

fadc4c72723d67a59d80d843c85b090ae22b463b test: Add txindex migration test (MarcoFalke)

Pull request description:

  Test for #22626

ACKs for top commit:
  theStack:
    Tested ACK fadc4c72723d67a59d80d843c85b090ae22b463b 🌁

Tree-SHA512: fc7133ef52826bf0d4fa2ac72c3f1bed4a185ff7492396552ff2cbf6531b053238039211a710cbb949379c56875cd7715f1ed49a514dd3b3f1b46554e3d4bef5

2 files changed, 93 insertions, 0 deletions

diff --git a/test/functional/feature_txindex_compatibility.py b/test/functional/feature_txindex_compatibility.py
new file mode 100755
index 0000000000..bbe1d1b537
--- /dev/null
+++ b/test/functional/feature_txindex_compatibility.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+# Copyright (c) 2021 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 that legacy txindex will be disabled on upgrade.
+
+Previous releases are required by this test, see test/README.md.
+"""
+
+import os
+import shutil
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.wallet import MiniWallet
+
+
+class MempoolCompatibilityTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 3
+        self.extra_args = [
+            ["-reindex", "-txindex"],
+            [],
+            [],
+        ]
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_previous_releases()
+
+    def setup_network(self):
+        self.add_nodes(
+            self.num_nodes,
+            self.extra_args,
+            versions=[
+                160300,  # Last release with legacy txindex
+                None,  # For MiniWallet, without migration code
+                200100,  # Any release with migration code (0.17.x - 22.x)
+            ],
+        )
+        self.start_nodes()
+        self.connect_nodes(0, 1)
+        self.connect_nodes(1, 2)
+
+    def run_test(self):
+        mini_wallet = MiniWallet(self.nodes[1])
+        mini_wallet.rescan_utxos()
+        spend_utxo = mini_wallet.get_utxo()
+        mini_wallet.send_self_transfer(from_node=self.nodes[1], utxo_to_spend=spend_utxo)
+        self.generate(self.nodes[1], 1)
+
+        self.log.info("Check legacy txindex")
+        self.nodes[0].getrawtransaction(txid=spend_utxo["txid"])  # Requires -txindex
+
+        self.stop_nodes()
+        legacy_chain_dir = os.path.join(self.nodes[0].datadir, self.chain)
+
+        self.log.info("Migrate legacy txindex")
+        migrate_chain_dir = os.path.join(self.nodes[2].datadir, self.chain)
+        shutil.rmtree(migrate_chain_dir)
+        shutil.copytree(legacy_chain_dir, migrate_chain_dir)
+        with self.nodes[2].assert_debug_log([
+                "Upgrading txindex database...",
+                "txindex is enabled at height 200",
+        ]):
+            self.start_node(2, extra_args=["-txindex"])
+        self.nodes[2].getrawtransaction(txid=spend_utxo["txid"])  # Requires -txindex
+
+        self.log.info("Drop legacy txindex")
+        drop_index_chain_dir = os.path.join(self.nodes[1].datadir, self.chain)
+        shutil.rmtree(drop_index_chain_dir)
+        shutil.copytree(legacy_chain_dir, drop_index_chain_dir)
+        self.nodes[1].assert_start_raises_init_error(
+            extra_args=["-txindex"],
+            expected_msg="Error: The block index db contains a legacy 'txindex'. To clear the occupied disk space, run a full -reindex, otherwise ignore this error. This error message will not be displayed again.",
+        )
+        # Build txindex from scratch and check there is no error this time
+        self.start_node(1, extra_args=["-txindex"])
+        self.nodes[2].getrawtransaction(txid=spend_utxo["txid"])  # Requires -txindex
+
+        self.stop_nodes()
+
+        self.log.info("Check migrated txindex can not be read by legacy node")
+        err_msg = f": You need to rebuild the database using -reindex to change -txindex.{os.linesep}Please restart with -reindex or -reindex-chainstate to recover."
+        shutil.rmtree(legacy_chain_dir)
+        shutil.copytree(migrate_chain_dir, legacy_chain_dir)
+        self.nodes[0].assert_start_raises_init_error(extra_args=["-txindex"], expected_msg=err_msg)
+        shutil.rmtree(legacy_chain_dir)
+        shutil.copytree(drop_index_chain_dir, legacy_chain_dir)
+        self.nodes[0].assert_start_raises_init_error(extra_args=["-txindex"], expected_msg=err_msg)
+
+
+if __name__ == "__main__":
+    MempoolCompatibilityTest().main()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index 2d84507151..37fc549922 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -296,6 +296,7 @@ BASE_SCRIPTS = [
     'rpc_deriveaddresses.py --usecli',
     'p2p_ping.py',
     'rpc_scantxoutset.py',
+    'feature_txindex_compatibility.py',
     'feature_logging.py',
     'feature_anchors.py',
     'feature_coinstatsindex.py',