SONARPY-2956 Rule S7510: Unnecessary <reversed> call around sorted() (#259)

GitOrigin-RevId: 745efcfcfbe6cc9c83275302d7a97b1633b81293

Author: maksim-grebeniuk-sonarsource

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

@@ -387,6 +387,7 @@ public Stream<Class<?>> getChecks() {
       UnencryptedSqsQueueCheck.class,
       UnencryptedEbsVolumeCheck.class,
       UnionTypeExpressionCheck.class,
+      UnnecessaryReversedCallCheck.class,
       UnquantifiedNonCapturingGroupCheck.class,
       UnreachableExceptCheck.class,
       UnreadPrivateAttributesCheck.class,

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

@@ -0,0 +1,80 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.python.checks;
+
+import javax.annotation.Nullable;
+import org.sonar.check.Rule;
+import org.sonar.plugins.python.api.PythonSubscriptionCheck;
+import org.sonar.plugins.python.api.SubscriptionContext;
+import org.sonar.plugins.python.api.tree.CallExpression;
+import org.sonar.plugins.python.api.tree.Expression;
+import org.sonar.plugins.python.api.tree.Name;
+import org.sonar.plugins.python.api.tree.RegularArgument;
+import org.sonar.plugins.python.api.tree.Tree;
+import org.sonar.plugins.python.api.types.v2.TriBool;
+import org.sonar.python.checks.utils.Expressions;
+import org.sonar.python.tree.TreeUtils;
+import org.sonar.python.types.v2.TypeCheckBuilder;
+
+@Rule(key = "S7510")
+public class UnnecessaryReversedCallCheck extends PythonSubscriptionCheck {
+  private TypeCheckBuilder isReversedTypeCheck;
+  private TypeCheckBuilder isSortedTypeCheck;
+
+  @Override
+  public void initialize(Context context) {
+    context.registerSyntaxNodeConsumer(Tree.Kind.FILE_INPUT, this::initChecks);
+    context.registerSyntaxNodeConsumer(Tree.Kind.CALL_EXPR, this::check);
+  }
+
+  private void initChecks(SubscriptionContext ctx) {
+    isReversedTypeCheck = ctx.typeChecker().typeCheckBuilder().isTypeWithName("reversed");
+    isSortedTypeCheck = ctx.typeChecker().typeCheckBuilder().isTypeWithName("sorted");
+  }
+
+  private void check(SubscriptionContext ctx) {
+    if (ctx.syntaxNode() instanceof CallExpression callExpression && isReversedCall(callExpression)) {
+      TreeUtils.nthArgumentOrKeywordOptional(0, "", callExpression.arguments())
+        .map(RegularArgument::expression)
+        .ifPresent(argumentExpression -> {
+          if (isSortedCall(argumentExpression) || isAssignedToSortedCall(argumentExpression)) {
+            ctx.addIssue(callExpression, "Remove this redundant reversed call, use reverse argument of the sorted function call instead");
+          }
+        });
+    }
+  }
+
+  private boolean isAssignedToSortedCall(Expression argumentExpression) {
+    return argumentExpression instanceof Name name
+           && getUsageCount(name) == 2
+           && isSortedCall(Expressions.singleAssignedValue(name));
+  }
+
+  private boolean isReversedCall(CallExpression callExpression) {
+    return isReversedTypeCheck.check(callExpression.callee().typeV2()) == TriBool.TRUE;
+  }
+
+  private boolean isSortedCall(@Nullable Expression expression) {
+    return expression instanceof CallExpression callExpression && isSortedTypeCheck.check(callExpression.callee().typeV2()) == TriBool.TRUE;
+  }
+
+  private static int getUsageCount(Name name) {
+    var symbol = name.symbolV2();
+    if (symbol == null) return 0;
+    return symbol.usages().size();
+  }
+}

python-checks/src/main/resources/org/sonar/l10n/py/rules/python/S7510.html

@@ -0,0 +1,25 @@
+<p>This rule raises an issue when the <code>reversed()</code> function is called with a <code>sorted()</code> as an argument.</p>
+<h2>Why is this an issue?</h2>
+<p>The <code>sorted()</code> function has a <code>reverse</code> parameter that provides the same functionality as the <code>reversed()</code>
+function.</p>
+<h2>How to fix it</h2>
+<p>Use the <code>reverse</code> parameter of the <code>sorted()</code> function to sort in descending order instead of using
+<code>reversed()</code>.</p>
+<h3>Code examples</h3>
+<h4>Noncompliant code example</h4>
+<pre data-diff-id="1" data-diff-type="noncompliant">
+data = [3, 1, 4, 1, 5, 9]
+result = reversed(sorted(data)) # Noncompliant
+</pre>
+<h4>Compliant solution</h4>
+<pre data-diff-id="1" data-diff-type="compliant">
+data = [3, 1, 4, 1, 5, 9]
+result = sorted(data, reverse=True)
+</pre>
+<h2>Resources</h2>
+<h3>Documentation</h3>
+<ul>
+  <li> Python reference documentation - <a href="https://docs.python.org/3/library/functions.html#sorted">sorted</a> </li>
+  <li> Python reference documentation - <a href="https://docs.python.org/3/library/functions.html#reversed">reversed</a> </li>
+</ul>
+

python-checks/src/main/resources/org/sonar/l10n/py/rules/python/S7510.json

@@ -0,0 +1,21 @@
+{
+  "title": "The \"sorted\" function call should not be passed to the \"reversed\" function as an argument",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "1min"
+  },
+  "tags": [],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-7510",
+  "sqKey": "S7510",
+  "scope": "All",
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "MAINTAINABILITY": "MEDIUM"
+    },
+    "attribute": "CONVENTIONAL"
+  }
+}

python-checks/src/main/resources/org/sonar/l10n/py/rules/python/Sonar_way_profile.json

@@ -259,6 +259,7 @@
     "S7491",
     "S7493",
     "S7499",
-    "S7501"
+    "S7501",
+    "S7510"
   ]
 }

python-checks/src/test/java/org/sonar/python/checks/UnnecessaryReversedCallCheckTest.java

@@ -0,0 +1,29 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.python.checks;
+
+import org.junit.jupiter.api.Test;
+import org.sonar.python.checks.utils.PythonCheckVerifier;
+
+class UnnecessaryReversedCallCheckTest {
+
+  @Test
+  void test() {
+    PythonCheckVerifier.verify("src/test/resources/checks/unnecessaryReversedCall.py", new UnnecessaryReversedCallCheck());
+  }
+
+}

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

@@ -0,0 +1,28 @@
+
+def case1():
+  data = [3, 1, 4, 1, 5, 9]
+  result = reversed(data)
+
+def case2():
+  data = [3, 1, 4, 1, 5, 9]
+  result = reversed(sorted(data)) # Noncompliant
+
+def case3():
+  data = [3, 1, 4, 1, 5, 9]
+  sorted_data = sorted(data)
+  result = reversed(sorted_data) # Noncompliant
+
+def case4():
+  data = [3, 1, 4, 1, 5, 9]
+  modified = sorted(data)
+  modified.append(3)
+  result = reversed(modified)
+
+def case5():
+  data = [3, 1, 4, 1, 5, 9]
+  result = reversed(list(data))
+
+def case6():
+  data = [3, 1, 4, 1, 5, 9]
+  list_data = list(data)
+  result = reversed(list_data)