Check for pointless statements (#1039)

With this commit we enable the linter error for pointless statements and
fix all existing issues.

Relates #838

.pylintrc

@@ -176,8 +176,6 @@ disable=print-statement,
         R0904,
         R0916,
         R1722,
-        W0104,
-        W0105,
         W0106,
         W0107,
         W0201,

esrally/mechanic/mechanic.py

@@ -439,12 +439,6 @@ def on_all_nodes_stopped(self):
 
 @thespian.actors.requireCapability('coordinator')
 class Dispatcher(actor.RallyActor):
-    def __init__(self):
-        super().__init__()
-        self.start_sender = None
-        self.pending = None
-        self.remotes = None
-
     """This Actor receives a copy of the startmsg (with the computed hosts
        attached) and creates a NodeMechanicActor on each targeted
        remote host.  It uses Thespian SystemRegistration to get
@@ -456,6 +450,12 @@ def __init__(self):
        Dispatcher.
     """
 
+    def __init__(self):
+        super().__init__()
+        self.start_sender = None
+        self.pending = None
+        self.remotes = None
+
     @actor.no_retry("mechanic dispatcher")
     def receiveMsg_StartEngine(self, startmsg, sender):
         self.start_sender = sender

esrally/metrics.py

@@ -238,10 +238,6 @@ class MetaInfoScope(Enum):
     """
     Cluster level meta-information is valid for all nodes in the cluster (e.g. the benchmarked Elasticsearch version)
     """
-    # host = 2
-    """
-    Host level meta-information is valid for all nodes on the same host (e.g. the OS name and version)
-    """
     node = 3
     """
     Node level meta-information is valid for a single node (e.g. GC times)
@@ -412,11 +408,11 @@ def flush(self, refresh=True):
         raise NotImplementedError("abstract method")
 
     def close(self):
-        self.logger.info("Closing metrics store.")
         """
         Closes the metric store. Note that it is mandatory to close the metrics store when it is no longer needed as it only persists
         metrics on close (in order to avoid additional latency during the benchmark).
         """
+        self.logger.info("Closing metrics store.")
         self.flush()
         self.clear_meta_info()
         self.opened = False

esrally/utils/opts.py

@@ -146,13 +146,13 @@ def __init__(self, argvalue):
 
     def parse_options(self):
         def normalize_to_dict(arg):
-            from elasticsearch.client import _normalize_hosts
             """
             Return parsed comma separated host string as dict with "default" key.
             This is needed to support backwards compatible --target-hosts for single clusters that are not
             defined as a json string or file.
             """
 
+            from elasticsearch.client import _normalize_hosts
             return {TargetHosts.DEFAULT: _normalize_hosts(arg)}
 
         self.parsed_options = to_dict(self.argvalue, default_parser=normalize_to_dict)

tests/mechanic/supplier_test.py

@@ -857,6 +857,7 @@ def test_missing_url(self):
             "release.cache": "true"
         }, template_renderer=renderer)
         with self.assertRaises(exceptions.SystemSetupError) as ctx:
+            # pylint: disable=pointless-statement
             # noinspection PyStatementEffect
             repo.download_url
         self.assertEqual("Neither config key [miss.url] nor [jdk.unbundled.miss_url] is defined.", ctx.exception.args[0])
@@ -868,6 +869,7 @@ def test_missing_cache(self):
             "runtime.jdk.bundled": "false"
         }, template_renderer=renderer)
         with self.assertRaises(exceptions.SystemSetupError) as ctx:
+            # pylint: disable=pointless-statement
             # noinspection PyStatementEffect
             repo.cache
         self.assertEqual("Mandatory config key [release.cache] is undefined.", ctx.exception.args[0])
@@ -880,6 +882,7 @@ def test_invalid_cache_value(self):
             "release.cache": "Invalid"
         }, template_renderer=renderer)
         with self.assertRaises(exceptions.SystemSetupError) as ctx:
+            # pylint: disable=pointless-statement
             # noinspection PyStatementEffect
             repo.cache
         self.assertEqual("Value [Invalid] for config key [release.cache] is not a valid boolean value.", ctx.exception.args[0])