new "'ThreadLocalRandom' instance might be shared" inspection

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/META-INF/InspectionGadgets.xml

@@ -2489,6 +2489,9 @@
     <localInspection language="JAVA" suppressId="LockAcquiredButNotSafelyReleased" shortName="SafeLock" bundle="com.siyeh.InspectionGadgetsBundle"
                      key="safe.lock.display.name" groupBundle="messages.InspectionsBundle" groupKey="group.names.threading.issues"
                      enabledByDefault="false" level="WARNING" implementationClass="com.siyeh.ig.threading.SafeLockInspection"/>
+    <localInspection language="JAVA" suppressId="SharedThreadLocalRandom" shortName="SharedThreadLocalRandom" bundle="com.siyeh.InspectionGadgetsBundle"
+                     key="shared.thread.local.random.display.name" groupBundle="messages.InspectionsBundle" groupKey="group.names.threading.issues"
+                     enabledByDefault="false" level="WARNING" implementationClass="com.siyeh.ig.threading.SharedThreadLocalRandomInspection"/>
     <localInspection language="JAVA" shortName="SignalWithoutCorrespondingAwait" bundle="com.siyeh.InspectionGadgetsBundle"
                      key="signal.without.corresponding.await.display.name" groupBundle="messages.InspectionsBundle"
                      groupKey="group.names.threading.issues" enabledByDefault="false" level="WARNING"

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/InspectionGadgetsBundle.properties

@@ -2068,4 +2068,6 @@ interface.may.be.annotated.functional.problem.descriptor=Interface <code>#ref</c
 only.report.public.methods.option=Only report 'public' methods
 lambda.parameter.hides.member.variable.display.name=Lambda parameter hides field
 lambda.parameter.hides.member.variable.problem.descriptor=Lambda parameter <code>#ref</code> hides field in class ''{0}'' #loc
+shared.thread.local.random.display.name='ThreadLocalRandom' instance might be shared
+shared.thread.local.random.problem.descriptor='ThreadLocalRandom' instance might be shared between threads
 

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/threading/SharedThreadLocalRandomInspection.java

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.siyeh.ig.threading;
+
+import com.intellij.psi.*;
+import com.intellij.psi.util.InheritanceUtil;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.siyeh.InspectionGadgetsBundle;
+import com.siyeh.ig.BaseInspection;
+import com.siyeh.ig.BaseInspectionVisitor;
+import com.siyeh.ig.psiutils.ParenthesesUtils;
+import com.siyeh.ig.psiutils.VariableAccessUtils;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NonNls;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class SharedThreadLocalRandomInspection extends BaseInspection {
+  @Nls
+  @NotNull
+  @Override
+  public String getDisplayName() {
+    return InspectionGadgetsBundle.message("shared.thread.local.random.display.name");
+  }
+
+  @NotNull
+  @Override
+  protected String buildErrorString(Object... infos) {
+    return InspectionGadgetsBundle.message("shared.thread.local.random.problem.descriptor");
+  }
+
+  @Override
+  public BaseInspectionVisitor buildVisitor() {
+    return new SharedThreadLocalRandomVisitor();
+  }
+
+  private static class SharedThreadLocalRandomVisitor extends BaseInspectionVisitor {
+
+    @Override
+    public void visitMethodCallExpression(PsiMethodCallExpression expression) {
+      super.visitMethodCallExpression(expression);
+      final PsiReferenceExpression methodExpression = expression.getMethodExpression();
+      @NonNls final String name = methodExpression.getReferenceName();
+      if (!"current".equals(name)) {
+        return;
+      }
+      final PsiMethod method = expression.resolveMethod();
+      if (method == null) {
+        return;
+      }
+      final PsiClass aClass = method.getContainingClass();
+      if (!InheritanceUtil.isInheritor(aClass, "java.util.concurrent.ThreadLocalRandom")) {
+        return;
+      }
+      if (isArgumentToMethodCall(expression)) {
+        registerMethodCallError(expression);
+      }
+      else {
+        final PsiVariable variable = assignedToVariable(expression);
+        if (variable instanceof PsiField) {
+          registerMethodCallError(expression);
+        }
+        else if (variable instanceof PsiLocalVariable) {
+          final PsiCodeBlock context = PsiTreeUtil.getParentOfType(variable, PsiCodeBlock.class);
+          if (VariableAccessUtils.variableIsPassedAsMethodArgument(variable, context) ||
+              VariableAccessUtils.variableIsUsedInInnerClass(variable, context)) {
+            registerMethodCallError(expression);
+          }
+        }
+      }
+    }
+
+    private static boolean isArgumentToMethodCall(PsiExpression expression) {
+      final PsiElement parent = ParenthesesUtils.getParentSkipParentheses(expression);
+      if (!(parent instanceof PsiExpressionList)) {
+        return false;
+      }
+      final PsiElement grandParent = parent.getParent();
+      return grandParent instanceof PsiMethodCallExpression;
+    }
+
+    private static PsiVariable assignedToVariable(PsiMethodCallExpression expression) {
+      final PsiElement parent = PsiTreeUtil.skipParentsOfType(expression, PsiParenthesizedExpression.class);
+      if (parent instanceof PsiVariable) {
+        return (PsiVariable)parent;
+      }
+      if (!(parent instanceof PsiAssignmentExpression)) {
+        return null;
+      }
+      final PsiAssignmentExpression assignmentExpression = (PsiAssignmentExpression)parent;
+      final PsiExpression rhs = assignmentExpression.getRExpression();
+      if (!PsiTreeUtil.isAncestor(rhs, expression, false)) {
+        return null;
+      }
+      final PsiExpression lhs = ParenthesesUtils.stripParentheses(assignmentExpression.getLExpression());
+      if (!(lhs instanceof PsiReferenceExpression)) {
+        return null;
+      }
+      final PsiReferenceExpression referenceExpression = (PsiReferenceExpression)lhs;
+      final PsiElement target = referenceExpression.resolve();
+      if (!(target instanceof PsiVariable)) {
+        return null;
+      }
+      return (PsiVariable)target;
+    }
+  }
+}

plugins/InspectionGadgets/src/inspectionDescriptions/SharedThreadLocalRandom.html

@@ -0,0 +1,15 @@
+<html>
+<body>
+Reports <b>java.util.concurrent.ThreadLocalRandom</b> instances which might be shared between threads.
+A <b>ThreadLocalRandom</b> might be shared between threads and is reported when it is assigned to a field,
+used as a method argument or assigned to a local variable and used in anonymous or nested classes.
+A <b>ThreadLocalRandom</b> should not be shared between threads because that is not thread-safe.
+<p>
+Usages of <b>ThreadLocalRandom</b> should typically look like <b>ThreadLocalRandom.current().nextInt(...)</b>
+(or <b>nextDouble(...)</b> etc.).
+When all usages are in this form, <b>ThreadLocalRandom</b> instances can not be used accidentally by multiple threads.
+<!-- tooltip end -->
+<p>
+<small>New in 13.1</small>
+</body>
+</html>

plugins/InspectionGadgets/testsrc/com/siyeh/ig/threading/SharedThreadLocalRandomInspectionTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.siyeh.ig.threading;
+
+import com.intellij.codeInspection.InspectionProfileEntry;
+import com.siyeh.ig.LightInspectionTestCase;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class SharedThreadLocalRandomInspectionTest extends LightInspectionTestCase {
+  @Override
+  protected InspectionProfileEntry getInspection() {
+    return new SharedThreadLocalRandomInspection();
+  }
+
+  @Override
+  protected String[] getEnvironmentClasses() {
+    return new String[] {
+      "package java.util.concurrent;\n" +
+      "import java.util.Random;" +
+      "public class ThreadLocalRandom extends Random {" +
+      "  public static ThreadLocalRandom current() {" +
+      "    return null;" +
+      "  }" +
+      "}"
+    };
+  }
+
+  public void testNoWarn() {
+    doStatementTest("System.out.println(java.util.concurrent.ThreadLocalRandom.current().nextInt());");
+  }
+
+  public void testArgument() {
+    doStatementTest("System.out.println(java.util.concurrent.ThreadLocalRandom./*'ThreadLocalRandom' instance might be shared between threads*/current/**/());");
+  }
+
+  public void testNoWarn2() {
+    doMemberTest("void m() {" +
+                 "  java.util.concurrent.ThreadLocalRandom r = java.util.concurrent.ThreadLocalRandom.current();" +
+                 "}");
+  }
+
+  public void testNestedClass() {
+    doMemberTest("void m() {" +
+                 "  java.util.concurrent.ThreadLocalRandom r = java.util.concurrent.ThreadLocalRandom./*'ThreadLocalRandom' instance might be shared between threads*/current/**/();" +
+                 "  class Z extends Thread {" +
+                 "    public void run() {" +
+                 "      System.out.println(r.nextInt(1));" +
+                 "    }" +
+                 "  }" +
+                 "}");
+  }
+
+  public void testAssignmentToField() {
+    doTest("import java.util.concurrent.ThreadLocalRandom;" +
+           "class A {" +
+           "  private ThreadLocalRandom r;" +
+           "  void m() {" +
+           "    r = ThreadLocalRandom./*'ThreadLocalRandom' instance might be shared between threads*/current/**/();" +
+           "  }" +
+           "}");
+  }
+}