ANS-219 Introduce RequestParamAnnotationCheck for invalid types

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamAnnotationCheck.java

@@ -0,0 +1,71 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.ALL;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.annotations;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.isSameType;
+import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
+import static com.google.errorprone.matchers.Matchers.isType;
+import static com.google.errorprone.matchers.Matchers.methodHasParameters;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.MethodTree;
+
+/**
+ * A {@link BugChecker} which flags {@code @RequestParam} parameters that have an invalid type.
+ *
+ * <p>Types considered invalid are {@code ImmutableMap} and subtypes of {@code ImmutableCollection}.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    name = "RequestParamAnnotationCheck",
+    summary = "Make sure all `@RequestParam` method parameters are valid",
+    linkType = BugPattern.LinkType.NONE,
+    severity = BugPattern.SeverityLevel.ERROR,
+    tags = BugPattern.StandardTags.LIKELY_ERROR)
+public final class RequestParamAnnotationCheck extends BugChecker implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final String ANN_PACKAGE_PREFIX = "org.springframework.web.bind.annotation.";
+
+  private static final Matcher<MethodTree> HAS_REQUEST_MAPPING_ANNOTATION =
+      allOf(
+          annotations(
+              ALL,
+              anyOf(
+                  isType(ANN_PACKAGE_PREFIX + "DeleteMapping"),
+                  isType(ANN_PACKAGE_PREFIX + "GetMapping"),
+                  isType(ANN_PACKAGE_PREFIX + "PatchMapping"),
+                  isType(ANN_PACKAGE_PREFIX + "PostMapping"),
+                  isType(ANN_PACKAGE_PREFIX + "PutMapping"),
+                  isType(ANN_PACKAGE_PREFIX + "RequestMapping"))),
+          methodHasParameters(
+              AT_LEAST_ONE,
+              annotations(AT_LEAST_ONE, anyOf(isType(ANN_PACKAGE_PREFIX + "RequestParam")))));
+
+  private static final Matcher<MethodTree> HAS_INVALID_REQUEST_PARAM_TYPE =
+      methodHasParameters(
+          AT_LEAST_ONE,
+          allOf(
+              annotations(ALL, anyOf(isType(ANN_PACKAGE_PREFIX + "RequestParam"))),
+              anyOf(
+                  isSubtypeOf("com.google.common.collect.ImmutableCollection"),
+                  isSameType("com.google.common.collect.ImmutableMap"))));
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    return HAS_REQUEST_MAPPING_ANNOTATION.matches(tree, state)
+            && HAS_INVALID_REQUEST_PARAM_TYPE.matches(tree, state)
+        ? buildDescription(tree)
+            .setMessage("At least one defined Request Parameters has an invalid type.")
+            .build()
+        : Description.NO_MATCH;
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/RequestParamAnnotationCheckTest.java

@@ -0,0 +1,46 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class RequestParamAnnotationCheckTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(RequestParamAnnotationCheck.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import java.util.List;",
+            "import java.util.Map;",
+            "import java.util.Set;",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableMap;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import org.springframework.web.bind.annotation.DeleteMapping;",
+            "import org.springframework.web.bind.annotation.GetMapping;",
+            "import org.springframework.web.bind.annotation.PostMapping;",
+            "import org.springframework.web.bind.annotation.PutMapping;",
+            "import org.springframework.web.bind.annotation.RequestBody;",
+            "import org.springframework.web.bind.annotation.RequestParam;",
+            "",
+            "interface A {",
+            "  @PostMapping A properRequestParam(@RequestBody String body);",
+            "  @GetMapping A properRequestParam(@RequestParam Integer param);",
+            "  @GetMapping A properRequestParam(@RequestParam List<String> param);",
+            "  @PostMapping A properRequestParam(@RequestBody String body, @RequestParam Set<String> param);",
+            "  @PutMapping A properRequestParam(@RequestBody String body, @RequestParam Map<String, String> param);",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @PostMapping A post(@RequestParam ImmutableList<String> param);",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @PutMapping A put(@RequestBody String body, @RequestParam ImmutableSet<String> param);",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @DeleteMapping A delete(@RequestBody String body, @RequestParam ImmutableMap<String, String> param);",
+            "}")
+        .doTest();
+  }
+}