Replace out instances of RateLimiter.create(rate, Duration.ZERO) (#…

…1958)

baseline-error-prone/src/main/java/com/palantir/baseline/errorprone/ZeroWarmupRateLimiter.java

@@ -0,0 +1,84 @@
+/*
+ * (c) Copyright 2021 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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.palantir.baseline.errorprone;
+
+import com.google.auto.service.AutoService;
+import com.google.common.util.concurrent.RateLimiter;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.BugPattern.LinkType;
+import com.google.errorprone.BugPattern.SeverityLevel;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.ChildMultiMatcher.MatchType;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.matchers.Matchers;
+import com.google.errorprone.matchers.method.MethodMatchers;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.tools.javac.code.Symbol;
+import com.sun.tools.javac.code.Symbol.VarSymbol;
+import java.time.Duration;
+
+@AutoService(BugChecker.class)
+@BugPattern(
+        name = "ZeroWarmupRateLimiter",
+        link = "https://github.com/palantir/gradle-baseline#baseline-error-prone-checks",
+        linkType = LinkType.CUSTOM,
+        severity = SeverityLevel.ERROR,
+        summary = "RateLimiters with zero warmup duration do not rate limit. "
+                + "Tracked at https://github.com/google/guava/issues/2730")
+public final class ZeroWarmupRateLimiter extends BugChecker implements BugChecker.MethodInvocationTreeMatcher {
+
+    private static final Matcher<ExpressionTree> MATCHER = Matchers.methodInvocation(
+            MethodMatchers.staticMethod()
+                    .onClass(RateLimiter.class.getName())
+                    .named("create")
+                    .withParameters("double", Duration.class.getName()),
+            MatchType.LAST,
+            ZeroWarmupRateLimiter::isDurationZero);
+
+    @Override
+    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+        if (MATCHER.matches(tree, state)) {
+            return buildDescription(tree)
+                    .addFix(SuggestedFix.replace(
+                            state.getEndPosition(tree.getArguments().get(0)),
+                            state.getEndPosition(tree.getArguments().get(1)),
+                            ""))
+                    .build();
+        }
+        return Description.NO_MATCH;
+    }
+
+    /**
+     * Returns true if the input tree is {@link Duration#ZERO}.
+     * Note this only supports the constant reference for now, not the value+unit overload or {@code Duration.ofX(0)}.
+     */
+    private static boolean isDurationZero(ExpressionTree expressionTree, VisitorState state) {
+        Symbol symbol = ASTHelpers.getSymbol(expressionTree);
+        if (symbol != null && symbol.isStatic() && symbol instanceof VarSymbol) {
+            VarSymbol varSymbol = (VarSymbol) symbol;
+            return varSymbol.name.contentEquals("ZERO")
+                    && state.getTypes()
+                            .isSameType(varSymbol.owner.type, state.getTypeFromString(Duration.class.getName()));
+        }
+        return false;
+    }
+}

baseline-error-prone/src/test/java/com/palantir/baseline/errorprone/ZeroWarmupRateLimiterTest.java

@@ -0,0 +1,87 @@
+/*
+ * (c) Copyright 2021 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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.palantir.baseline.errorprone;
+
+import org.junit.jupiter.api.Test;
+
+class ZeroWarmupRateLimiterTest {
+
+    @Test
+    public void should_remove_duration_zero() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.util.concurrent.RateLimiter;",
+                        "import java.time.Duration;",
+                        "class Test {",
+                        "  void f() {",
+                        "    RateLimiter.create(10, Duration.ZERO);",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import com.google.common.util.concurrent.RateLimiter;",
+                        "import java.time.Duration;",
+                        "class Test {",
+                        "  void f() {",
+                        "    RateLimiter.create(10);",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    public void should_remove_duration_zero_static_import() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.util.concurrent.RateLimiter;",
+                        "import static java.time.Duration.ZERO;",
+                        "class Test {",
+                        "  void f() {",
+                        "    RateLimiter.create(10, ZERO);",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import com.google.common.util.concurrent.RateLimiter;",
+                        "import static java.time.Duration.ZERO;",
+                        "class Test {",
+                        "  void f() {",
+                        "    RateLimiter.create(10);",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    public void should_not_modify_existing_uses() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.util.concurrent.RateLimiter;",
+                        "import java.time.Duration;",
+                        "class Test {",
+                        "  void f() {",
+                        "    RateLimiter.create(10, Duration.ofMillis(100));",
+                        "  }",
+                        "}")
+                .expectUnchanged()
+                .doTest();
+    }
+
+    private RefactoringValidator fix() {
+        return RefactoringValidator.of(ZeroWarmupRateLimiter.class, getClass());
+    }
+}

changelog/@unreleased/pr-1958.v2.yml

@@ -0,0 +1,6 @@
+type: fix
+fix:
+  description: Replace out instances of `RateLimiter.create(rate, Duration.ZERO)`
+    which do not rate limit at all. See https://github.com/google/guava/issues/2730
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1958

gradle-baseline-java/src/main/groovy/com/palantir/baseline/extensions/BaselineErrorProneExtension.java

@@ -76,6 +76,7 @@ public class BaselineErrorProneExtension {
             // "ThrowSpecificity",
             "UnsafeGaugeRegistration",
             "VarUsage",
+            "ZeroWarmupRateLimiter",
 
             // Built-in checks
             "ArrayEquals",