Merge #19781: test: add parameterized constructor for msg_sendcmpct()

6384419 test: add parameterized constructor for msg_sendcmpct() (Sebastian Falbesoner)

Pull request description:

  While working on the test for #19776 I noticed that creating a `sendcmpct` message is quite cumbersome -- due to the lack of a parameterized constructor, one needs to create an empty (that is, initialized with default values) object and then set the two fields one by one. This PR replaces the default constructor with a parameterized constructor and uses it in the test `p2p_compactblocks.py`, reducing LOC. No need to pollute the namespace with temporary throw-away message objects anymore.

ACKs for top commit:
  guggero:
    Code review ACK 6384419.
  epson121:
    Code review ACK 6384419

Tree-SHA512: 3b58d276d714b73abc6cc98d1d52dec5f6026b33f03faaeb7dcbc5d83ac377555179f98b159b2b9ecc8957999c35a1dc082e3c69299c5fde4e35f1bd0587ce9d

Author: MarcoFalke

test/functional/p2p_compactblocks.py

@@ -188,28 +188,21 @@ def check_announcement_of_new_block(node, peer, predicate):
         test_node.request_headers_and_sync(locator=[tip])
 
         # Now try a SENDCMPCT message with too-high version
-        sendcmpct = msg_sendcmpct()
-        sendcmpct.version = preferred_version + 1
-        sendcmpct.announce = True
-        test_node.send_and_ping(sendcmpct)
+        test_node.send_and_ping(msg_sendcmpct(announce=True, version=preferred_version+1))
         check_announcement_of_new_block(node, test_node, lambda p: "cmpctblock" not in p.last_message)
 
         # Headers sync before next test.
         test_node.request_headers_and_sync(locator=[tip])
 
         # Now try a SENDCMPCT message with valid version, but announce=False
-        sendcmpct.version = preferred_version
-        sendcmpct.announce = False
-        test_node.send_and_ping(sendcmpct)
+        test_node.send_and_ping(msg_sendcmpct(announce=False, version=preferred_version))
         check_announcement_of_new_block(node, test_node, lambda p: "cmpctblock" not in p.last_message)
 
         # Headers sync before next test.
         test_node.request_headers_and_sync(locator=[tip])
 
         # Finally, try a SENDCMPCT message with announce=True
-        sendcmpct.version = preferred_version
-        sendcmpct.announce = True
-        test_node.send_and_ping(sendcmpct)
+        test_node.send_and_ping(msg_sendcmpct(announce=True, version=preferred_version))
         check_announcement_of_new_block(node, test_node, lambda p: "cmpctblock" in p.last_message)
 
         # Try one more time (no headers sync should be needed!)
@@ -220,23 +213,17 @@ def check_announcement_of_new_block(node, peer, predicate):
         check_announcement_of_new_block(node, test_node, lambda p: "cmpctblock" in p.last_message)
 
         # Try one more time, after sending a version-1, announce=false message.
-        sendcmpct.version = preferred_version - 1
-        sendcmpct.announce = False
-        test_node.send_and_ping(sendcmpct)
+        test_node.send_and_ping(msg_sendcmpct(announce=False, version=preferred_version-1))
         check_announcement_of_new_block(node, test_node, lambda p: "cmpctblock" in p.last_message)
 
         # Now turn off announcements
-        sendcmpct.version = preferred_version
-        sendcmpct.announce = False
-        test_node.send_and_ping(sendcmpct)
+        test_node.send_and_ping(msg_sendcmpct(announce=False, version=preferred_version))
         check_announcement_of_new_block(node, test_node, lambda p: "cmpctblock" not in p.last_message and "headers" in p.last_message)
 
         if old_node is not None:
             # Verify that a peer using an older protocol version can receive
             # announcements from this node.
-            sendcmpct.version = preferred_version - 1
-            sendcmpct.announce = True
-            old_node.send_and_ping(sendcmpct)
+            old_node.send_and_ping(msg_sendcmpct(announce=True, version=preferred_version-1))
             # Header sync
             old_node.request_headers_and_sync(locator=[tip])
             check_announcement_of_new_block(node, old_node, lambda p: "cmpctblock" in p.last_message)
@@ -729,11 +716,7 @@ def request_cb_announcements(self, peer):
         node = self.nodes[0]
         tip = node.getbestblockhash()
         peer.get_headers(locator=[int(tip, 16)], hashstop=0)
-
-        msg = msg_sendcmpct()
-        msg.version = peer.cmpct_version
-        msg.announce = True
-        peer.send_and_ping(msg)
+        peer.send_and_ping(msg_sendcmpct(announce=True, version=peer.cmpct_version))
 
     def test_compactblock_reconstruction_multiple_peers(self, stalling_peer, delivery_peer):
         node = self.nodes[0]

test/functional/test_framework/messages.py

@@ -1472,9 +1472,9 @@ class msg_sendcmpct:
     __slots__ = ("announce", "version")
     msgtype = b"sendcmpct"
 
-    def __init__(self):
-        self.announce = False
-        self.version = 1
+    def __init__(self, announce=False, version=1):
+        self.announce = announce
+        self.version = version
 
     def deserialize(self, f):
         self.announce = struct.unpack("<?", f.read(1))[0]