Merge bitcoin/bitcoin#26660: test: Use last release in compatibility tests

fabb24c test: Use last release in compatibility tests (MarcoFalke)

Pull request description:

  In compatibility tests it makes sense to always use the last release without the new feature, as it is likely more in use than any even older previous release.

ACKs for top commit:
  Sjors:
    utACK fabb24c

Tree-SHA512: beb854f4d28ba313282e1e0303abb0e09377828b138bde5a3e209337210b6b4c24855ab90a68f8789387001e4ca33b15cc37dbc9b7809929f4e7d1b69833a527

Author: MarcoFalke

test/functional/feature_txindex_compatibility.py

@@ -14,7 +14,7 @@
 from test_framework.wallet import MiniWallet
 
 
-class MempoolCompatibilityTest(BitcoinTestFramework):
+class TxindexCompatibilityTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 3
         self.extra_args = [
@@ -33,7 +33,7 @@ def setup_network(self):
             versions=[
                 160300,  # Last release with legacy txindex
                 None,  # For MiniWallet, without migration code
-                200100,  # Any release with migration code (0.17.x - 22.x)
+                220000,  # Last release with migration code (0.17.x - 22.x)
             ],
         )
         self.start_nodes()
@@ -89,4 +89,4 @@ def run_test(self):
 
 
 if __name__ == "__main__":
-    MempoolCompatibilityTest().main()
+    TxindexCompatibilityTest().main()

test/functional/mempool_compatibility.py

@@ -7,7 +7,7 @@
 NOTE: The test is designed to prevent cases when compatibility is broken accidentally.
 In case we need to break mempool compatibility we can continue to use the test by just bumping the version number.
 
-The previous release v0.19.1 is required by this test, see test/README.md.
+Previous releases are required by this test, see test/README.md.
 """
 
 import os
@@ -29,7 +29,7 @@ def skip_test_if_missing_module(self):
 
     def setup_network(self):
         self.add_nodes(self.num_nodes, versions=[
-            190100,  # oldest version with getmempoolinfo.loaded (used to avoid intermittent issues)
+            200100,  # Last release with previous mempool format
             None,
         ])
         self.start_nodes()
@@ -38,6 +38,7 @@ def run_test(self):
         self.log.info("Test that mempool.dat is compatible between versions")
 
         old_node, new_node = self.nodes
+        assert "unbroadcastcount" not in old_node.getmempoolinfo()
         new_wallet = MiniWallet(new_node, mode=MiniWalletMode.RAW_P2PK)
         self.generate(new_wallet, 1, sync_fun=self.no_op)
         self.generate(new_node, COINBASE_MATURITY, sync_fun=self.no_op)