ban assert (#1810)

Introduce `BadAssert` to ban `assert` statements in favor of better alternatives.

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

@@ -0,0 +1,86 @@
+/*
+ * (c) Copyright 2020 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.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.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.CompileTimeConstantExpressionMatcher;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AssertTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.tools.javac.code.Type;
+
+@AutoService(BugChecker.class)
+@BugPattern(
+        name = "BadAssert",
+        link = "https://github.com/palantir/gradle-baseline#baseline-error-prone-checks",
+        linkType = LinkType.CUSTOM,
+        severity = SeverityLevel.ERROR,
+        summary = "Assert statements should not be used. Asserts are generally enabled in tests but disabled in "
+                + "production, which means code can execute in production that is impossible to test.\n"
+                + "If you're confident that an 'assert' is required, this check may be suppressed using "
+                + "@SuppressWarnings(\"BadAssert\")")
+public final class BadAssert extends BugChecker implements BugChecker.AssertTreeMatcher {
+
+    private static final String LOGSAFE_PRECONDITIONS = "com.palantir.logsafe.Preconditions";
+    private final Matcher<ExpressionTree> compileTimeConstExpressionMatcher =
+            new CompileTimeConstantExpressionMatcher();
+
+    @Override
+    public Description matchAssert(AssertTree tree, VisitorState state) {
+        ExpressionTree condition = tree.getCondition();
+        ExpressionTree detail = tree.getDetail();
+        SuggestedFix.Builder fix = SuggestedFix.builder();
+        if (detail == null) {
+            fix.replace(
+                    tree,
+                    String.format(
+                            "if (!%s) { throw new IllegalStateException(); }", state.getSourceForNode(condition)));
+        } else if (isString(ASTHelpers.getType(detail), state)
+                && compileTimeConstExpressionMatcher.matches(detail, state)) {
+            fix.replace(
+                    tree,
+                    String.format(
+                            "%s.checkState(%s, %s)",
+                            SuggestedFixes.qualifyType(state, fix, LOGSAFE_PRECONDITIONS),
+                            state.getSourceForNode(condition),
+                            state.getSourceForNode(detail)));
+        } else {
+            String message = isString(ASTHelpers.getType(detail), state)
+                    ? state.getSourceForNode(detail)
+                    : "String.valueOf(" + state.getSourceForNode(detail) + ")";
+            fix.replace(
+                    tree,
+                    String.format(
+                            "if (!%s) { throw new IllegalStateException(%s); }",
+                            state.getSourceForNode(condition), message));
+        }
+        return buildDescription(tree).addFix(fix.build()).build();
+    }
+
+    private static boolean isString(Type type, VisitorState state) {
+        return state.getTypes().isSameType(type, state.getTypeFromString(String.class.getName()));
+    }
+}

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

@@ -0,0 +1,112 @@
+/*
+ * (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;
+
+final class BadAssertTest {
+
+    @Test
+    void testNoDescription() {
+        fix().addInputLines(
+                        "Test.java",
+                        // format-hint
+                        "public class Test {",
+                        "  void f(boolean in) {",
+                        "    assert in;",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "public class Test {",
+                        "  void f(boolean in) {",
+                        "    if (!in) {",
+                        "        throw new IllegalStateException();",
+                        "    }",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    void testConstantStringDescription() {
+        fix().addInputLines(
+                        "Test.java",
+                        "public class Test {",
+                        "  void f(boolean in) {",
+                        "    assert in : \"oops\";",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import com.palantir.logsafe.Preconditions;",
+                        "public class Test {",
+                        "  void f(boolean in) {",
+                        "    Preconditions.checkState(in, \"oops\");",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    void testConstantNonStringDescription() {
+        fix().addInputLines(
+                        "Test.java",
+                        // format-hint
+                        "public class Test {",
+                        "  void f(boolean in) {",
+                        "    assert in : 1;",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "public class Test {",
+                        "  void f(boolean in) {",
+                        "    if (!in) {",
+                        "        throw new IllegalStateException(String.valueOf(1));",
+                        "    }",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    void testNonConstantStringDescription() {
+        fix().addInputLines(
+                        "Test.java",
+                        // format-hint
+                        "public class Test {",
+                        "  void f(boolean in, String desc) {",
+                        "    assert in : desc;",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "public class Test {",
+                        "  void f(boolean in, String desc) {",
+                        "    if (!in) {",
+                        "        throw new IllegalStateException(desc);",
+                        "    }",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    private RefactoringValidator fix() {
+        return RefactoringValidator.of(BadAssert.class, getClass());
+    }
+}

changelog/@unreleased/pr-1810.v2.yml

@@ -0,0 +1,6 @@
+type: improvement
+improvement:
+  description: Introduce `BadAssert` to ban `assert` statements in favor of better
+    alternatives.
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1810