*: Fix many ResourceWarnings

--------
kirr:

Currently running ZEO tests emits lots of ResourceWarning, for example

    test_ZEO_DB_convenience_error (ZEO.tests.testZEO.Test_convenience_functions).../lib/python3.9/site-packages/mock/mock.py:2119: ResourceWarning: unclosed file <_io.FileIO name=4 mode='rb+' closefd=True>
    test_ZEO_connection_convenience_ok (ZEO.tests.testZEO.Test_convenience_functions).../lib/python3.9/site-packages/mock/mock.py:2072: ResourceWarning: unclosed file <_io.FileIO name=4 mode='rb+' closefd=True>
    some_basic_locking_tests (ZEO.tests.testZEO2)/usr/lib/python3.9/logging/__init__.py:1063: ResourceWarning: unclosed <socket.socket fd=10, family=AddressFamily.AF_UNIX, type=SocketKind.SOCK_STREAM, proto=0, laddr=x>
    ...

The patch "asyncio.client: Fix bugs in closing and connecting logic"
fixed closing/connecting asyncio bugs that were indicated by some
ResourceWarnings. However there are more ResourceWarnings that are
correctly emitted due to e.g. not closed IO or uncompleted transactions.

-> Fix them.

Extracted from #195
More details at: #195 (comment)

src/ZEO/StorageServer.py

@@ -607,7 +607,9 @@ def iterator_record_next(self, iid):
 
     def iterator_gc(self, iids):
         for iid in iids:
-            self._iterators.pop(iid, None)
+            it = self._iterators.pop(iid, None)
+            if hasattr(it, "close"):
+                it.close()
 
     def server_status(self):
         return self.server.server_status(self.storage_id)

src/ZEO/asyncio/tests.py

@@ -530,6 +530,8 @@ def test_multiple_addresses(self):
         transport = loop.transport
         protocol.data_received(sized(self.enc + b'5'))
         self.assertEqual(self.unsized(transport.pop(2)), self.enc + b'5')
+        # cancel the heartbeat to make debugging easier
+        protocol.heartbeat_handle.cancel()
         self.respond(1, None)
 
         # Now, when the first connection fails, it won't be retried,

src/ZEO/nagios.py

@@ -77,6 +77,7 @@ def check(addr, output_metrics, status, per):
     try:
         s.connect(addr)
     except socket.error as err:
+        s.close()
         return error("Can't connect %s" % err)
 
     s.sendall(b'\x00\x00\x00\x04ruok')

src/ZEO/tests/CommitLockTests.py

@@ -49,7 +49,10 @@ def testrun(self):
             self.myvote()
             self.storage.tpc_finish(self.trans)
         except ClientDisconnected:
-            pass
+            self.storage.tpc_abort(self.trans)
+        except Exception:
+            self.storage.tpc_abort(self.trans)
+            raise
 
     def myvote(self):
         # The vote() call is synchronous, which makes it difficult to
@@ -77,7 +80,11 @@ class CommitLockTests(object):
     # This causes the commit lock code to be exercised.  Once the
     # other connections are started, the first transaction completes.
 
+    txn = None
+
     def _cleanup(self):
+        if self.txn is not None:
+            self._storage.tpc_abort(self.txn)
         for store, trans in self._storages:
             store.tpc_abort(trans)
             store.close()
@@ -88,6 +95,7 @@ def _start_txn(self):
         self._storage.tpc_begin(txn)
         oid = self._storage.new_oid()
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(1)), '', txn)
+        self.txn = txn
         return oid, txn
 
     def _begin_threads(self):

src/ZEO/tests/ConnectionTests.py

@@ -992,6 +992,7 @@ def checkTimeout(self):
             else:
                 self.fail('bad logging')
 
+        storage.tpc_abort(txn)
         storage.close()
 
     def checkTimeoutOnAbort(self):
@@ -1038,6 +1039,7 @@ def checkTimeoutAfterVote(self):
         # Load should fail since the object should not be in either the cache
         # or the server.
         self.assertRaises(KeyError, storage.load, oid, '')
+        storage.tpc_abort(t)
 
 
 class MSTThread(threading.Thread):

src/ZEO/tests/IterationTests.py

@@ -155,6 +155,8 @@ def checkIteratorGCStorageDisconnect(self):
         # calling tpc_abort implicitly.
         self._storage.notify_disconnected()
         self.assertEqual(0, len(self._storage._iterator_ids))
+        # maybe, ``notify_disconnected`` should automatically clean up
+        self._storage.tpc_abort(t)  # avoid ``ResourceWarning``
 
     def checkIteratorParallel(self):
         self._dostore()

src/ZEO/tests/testZEO.py

@@ -85,10 +85,12 @@ def test_ZEO_client_convenience(self):
         import ZEO
 
         client_thread = mock.Mock(
-            spec=['call', 'async', 'async_iter', 'wait'])
+            spec=['call', 'async', 'async_iter', 'wait', 'close'])
         client = ZEO.client(
             8001, wait=False, _client_factory=client_thread)
         self.assertIsInstance(client, ClientStorage)
+        client.close()
+        client._cache.close()  # client thread responsibility
 
     def test_ZEO_DB_convenience_ok(self):
         import mock
@@ -766,6 +768,7 @@ def checkTransactionBufferCleanup(self):
         self._storage.tpc_begin(t)
         self._storage.storeBlob(
           oid, ZODB.utils.z64, 'foo', 'blob_file', '', t)
+        self._storage.tpc_abort(t)
         self._storage.close()
 
 

src/ZEO/tests/testZEO2.py

@@ -107,6 +107,8 @@ def proper_handling_of_blob_conflicts():
     >>> logger.removeHandler(handler)
     >>> zs2.tpc_abort('1')
     >>> fs.close()
+
+    >>> server.close()
     """
 
 
@@ -192,6 +194,8 @@ def errors_in_vote_should_clear_lock():
     True
 
     >>> zs.tpc_abort('1')
+
+    >>> server.close()
     """
 
 

src/ZEO/tests/test_cache.py

@@ -151,6 +151,7 @@ def testEviction(self):
 
         # TODO:  Need to make sure eviction of non-current data
         # are handled correctly.
+        cache.close()
 
     def testSerialization(self):
         self.cache.store(n1, n2, None, b"data for n1")
@@ -206,6 +207,7 @@ def testOldObjectLargerThanCache(self):
         # If an object cannot be stored in the cache, it must not be
         # recorded as non-current.
         self.assertTrue(1 not in cache.noncurrent)
+        cache.close()
 
     def testVeryLargeCaches(self):
         cache = ZEO.cache.ClientCache('cache', size=(1 << 32)+(1 << 20))