SONARPY-1006 S1172: Avoid raising issues when the parameter name starts with "_" (#1117)

Author: guillaume-dequenne

its/ruling/src/test/resources/expected/python-S1172.json

@@ -211,9 +211,6 @@
 184,
 555,
 ],
-'project:buildbot-0.8.6p1/buildbot/status/web/change_hook.py':[
-81,
-],
 'project:buildbot-0.8.6p1/buildbot/status/web/hooks/base.py':[
 23,
 ],
@@ -222,20 +219,13 @@
 100,
 100,
 ],
-'project:buildbot-0.8.6p1/buildbot/steps/source/svn.py':[
-373,
-],
 'project:buildbot-0.8.6p1/buildbot/test/fake/fakedb.py':[
 354,
-628,
 957,
 ],
 'project:buildbot-0.8.6p1/buildbot/test/fake/remotecommand.py':[
 38,
 ],
-'project:buildbot-0.8.6p1/buildbot/util/eventual.py':[
-94,
-],
 'project:buildbot-0.8.6p1/contrib/buildbot_cvs_mail.py':[
 64,
 64,
@@ -637,7 +627,6 @@
 'project:django-2.2.3/django/utils/six.py':[
 182,
 539,
-687,
 ],
 'project:django-2.2.3/django/utils/translation/reloader.py':[
 7,
@@ -1087,9 +1076,6 @@
 232,
 432,
 ],
-'project:numpy-1.16.4/numpy/distutils/exec_command.py':[
-196,
-],
 'project:numpy-1.16.4/numpy/distutils/fcompiler/__init__.py':[
 796,
 ],
@@ -1144,15 +1130,9 @@
 1099,
 1099,
 ],
-'project:tensorflow/python/autograph/pyct/inspect_utils_test.py':[
-49,
-],
 'project:tensorflow/python/compiler/tensorrt/test/conv2d_test.py':[
 67,
 ],
-'project:tensorflow/python/data/experimental/kernel_tests/group_by_window_test.py':[
-147,
-],
 'project:tensorflow/python/debug/lib/debug_service_pb2_grpc.py':[
 63,
 76,
@@ -1164,18 +1144,9 @@
 'project:tensorflow/python/keras/engine/base_layer_utils.py':[
 67,
 ],
-'project:tensorflow/python/keras/layers/convolutional_recurrent.py':[
-569,
-],
-'project:tensorflow/python/keras/layers/cudnn_recurrent.py':[
-451,
-],
 'project:tensorflow/python/keras/layers/legacy_rnn/rnn_cell_wrapper_impl.py':[
 206,
 ],
-'project:tensorflow/python/keras/layers/recurrent.py':[
-2376,
-],
 'project:tensorflow/python/keras/saving/saved_model_experimental.py':[
 367,
 367,
@@ -1204,25 +1175,13 @@
 'project:tensorflow/python/kernel_tests/signal/mel_ops_test.py':[
 62,
 ],
-'project:tensorflow/python/kernel_tests/sparse_tensor_dense_matmul_op_test.py':[
-389,
-],
-'project:tensorflow/python/kernel_tests/sparse_xent_op_test.py':[
-356,
-],
-'project:tensorflow/python/ops/ctc_ops.py':[
-241,
-690,
-],
 'project:tensorflow/python/ops/data_flow_ops.py':[
 1935,
 ],
 'project:tensorflow/python/ops/rnn.py':[
 158,
 ],
 'project:tensorflow/python/ops/variables.py':[
-53,
-58,
 182,
 223,
 ],
@@ -1270,12 +1229,6 @@
 140,
 140,
 ],
-'project:tensorflow/tools/pip_package/simple_console.py':[
-26,
-],
-'project:tensorflow/tools/pip_package/simple_console_for_windows.py':[
-26,
-],
 'project:tensorflow/tools/test/system_info.py':[
 25,
 ],

python-checks/src/main/java/org/sonar/python/checks/UnusedFunctionParameterCheck.java

@@ -54,13 +54,17 @@ public void initialize(Context context) {
   private static void checkFunctionParameter(SubscriptionContext ctx, FunctionDef functionDef) {
     if (isException(ctx, functionDef)) return;
     functionDef.localVariables().stream()
-      .filter(symbol -> !"self".equals(symbol.name()))
+      .filter(symbol -> !isIgnoredSymbolName(symbol.name()))
       .map(Symbol::usages)
       .filter(usages -> usages.size() == 1 && usages.get(0).tree().parent().is(Kind.PARAMETER))
       .map(usages -> (Parameter) usages.get(0).tree().parent())
       .forEach(param -> ctx.addIssue(param, String.format(MESSAGE, param.name().name())));
   }
 
+  private static boolean isIgnoredSymbolName(String symbolName) {
+    return "self".equals(symbolName) || symbolName.startsWith("_");
+  }
+
   private static boolean isException(SubscriptionContext ctx, FunctionDef functionDef) {
     FunctionSymbol functionSymbol = ((FunctionDefImpl) functionDef).functionSymbol();
     return CheckUtils.containsCallToLocalsFunction(functionDef) ||

python-checks/src/test/resources/checks/unusedFunctionParameter/unusedFunctionParameter.py

@@ -125,3 +125,8 @@ def bar(q, r=None):
 
 def test_using_fixture(my_fixture):
     assert do_something() == expected()
+
+
+def lambda_handler(_event, _context):
+    print("foo")
+