Merge bitcoin/bitcoin#22490: test: Disable automatic connections per default in the functional tests

8ca51af1ece371b6f1bdb88b96f16020cc787d13 test: Disable automatic connections by default (Martin Zumsande)

Pull request description:

  A node normally doesn't make automatic connections to peers in the functional tests because neither DNS seeds nor hardcoded peers are available on regtest. However, when random entries are inserted into addrman as part of a functional test (e.g. while testing addr relay), `ThreadOpenConnections` will periodically try to connect to them, resulting in log entries such as:
  `[opencon] [net.cpp:400] [ConnectNode] trying connection 18.166.1.1:8333 lastseen=0.0hrs`

  I don't think it's desirable that functional tests try to connect to random computers on the internet, aside from the possibility that at some point in time someone out there might actually answer in a way to ruin a test.

  This PR fixes this problem by disabling  `ThreadOpenConnections` by adding `-connect=0` to the default args, and adding exceptions only when needed for the test to pass.

ACKs for top commit:
  tryphe:
    Concept ACK, light code review ACK 8ca51af1ece371b6f1bdb88b96f16020cc787d13

Tree-SHA512: bcfb2de610e6c35a97a2bd7ad6267e968b1ac7529638d99276993cd5bc93ce9919d54e22d6dc84e1b02ecd626ab6554e201693552ea065c29794eece38c43f7d

1 files changed, 5 insertions, 3 deletions

diff --git a/test/functional/test_framework/util.py b/test/functional/test_framework/util.py
index b0f15ddafe..a9a6adcfc8 100644
--- a/test/functional/test_framework/util.py
+++ b/test/functional/test_framework/util.py
@@ -337,17 +337,17 @@ def rpc_url(datadir, i, chain, rpchost):
 ################
 
 
-def initialize_datadir(dirname, n, chain):
+def initialize_datadir(dirname, n, chain, disable_autoconnect=True):
     datadir = get_datadir_path(dirname, n)
     if not os.path.isdir(datadir):
         os.makedirs(datadir)
-    write_config(os.path.join(datadir, "bitcoin.conf"), n=n, chain=chain)
+    write_config(os.path.join(datadir, "bitcoin.conf"), n=n, chain=chain, disable_autoconnect=disable_autoconnect)
     os.makedirs(os.path.join(datadir, 'stderr'), exist_ok=True)
     os.makedirs(os.path.join(datadir, 'stdout'), exist_ok=True)
     return datadir
 
 
-def write_config(config_path, *, n, chain, extra_config=""):
+def write_config(config_path, *, n, chain, extra_config="", disable_autoconnect=True):
     # Translate chain subdirectory name to config name
     if chain == 'testnet3':
         chain_name_conf_arg = 'testnet'
@@ -375,6 +375,8 @@ def write_config(config_path, *, n, chain, extra_config=""):
         f.write("shrinkdebugfile=0\n")
         # To improve SQLite wallet performance so that the tests don't timeout, use -unsafesqlitesync
         f.write("unsafesqlitesync=1\n")
+        if disable_autoconnect:
+            f.write("connect=0\n")
         f.write(extra_config)