Added support for static enums getting fixed from Sonar (#244)

This was quite fast to add, and it looks like one that might be quite to
do without Sonar, but it is help proving the concept regardless.

Author: nahsra

core-codemods/src/main/java/io/codemodder/codemods/FixRedundantStaticOnEnumCodemod.java

@@ -0,0 +1,38 @@
+package io.codemodder.codemods;
+
+import com.github.javaparser.ast.CompilationUnit;
+import com.github.javaparser.ast.body.EnumDeclaration;
+import io.codemodder.*;
+import io.codemodder.providers.sonar.ProvidedSonarScan;
+import io.codemodder.providers.sonar.RuleIssues;
+import io.codemodder.providers.sonar.SonarPluginJavaParserChanger;
+import io.codemodder.providers.sonar.api.Issue;
+import javax.inject.Inject;
+
+/** A codemod for automatically removing redundant static flags on nested enums. */
+@Codemod(
+    id = "sonar:java/remove-redundant-static-s2786",
+    reviewGuidance = ReviewGuidance.MERGE_WITHOUT_REVIEW,
+    executionPriority = CodemodExecutionPriority.HIGH)
+public final class FixRedundantStaticOnEnumCodemod
+    extends SonarPluginJavaParserChanger<EnumDeclaration> {
+
+  @Inject
+  public FixRedundantStaticOnEnumCodemod(
+      @ProvidedSonarScan(ruleId = "java:S2786") final RuleIssues issues) {
+    super(issues, EnumDeclaration.class, RegionNodeMatcher.MATCHES_START);
+  }
+
+  @Override
+  public boolean onIssueFound(
+      final CodemodInvocationContext context,
+      final CompilationUnit cu,
+      final EnumDeclaration enumDecl,
+      final Issue issue) {
+    if (enumDecl.isStatic()) {
+      enumDecl.setStatic(false);
+      return true;
+    }
+    return false;
+  }
+}

core-codemods/src/main/resources/io/codemodder/codemods/FixRedundantStaticOnEnumCodemod/description.md

@@ -0,0 +1,15 @@
+This change removes redundant (and possibly misleading) `static` keywords on `enum` types defined within classes. All `enum` types that are nested within another type are automatically `static`, and so listing the flag this clutters the code, and may cause confusion when reasoning about it.
+
+Our changes look something like this:
+
+```diff
+  @RestController
+  final class CheckStatusController {
+
+-   static enum ResponseType {  
++   enum ResponseType {
+      SUCCESS,
+      FAILURE,
+      ERROR
+    }
+```

core-codemods/src/main/resources/io/codemodder/codemods/FixRedundantStaticOnEnumCodemod/report.json

@@ -0,0 +1,7 @@
+{
+  "summary" : "Removed redundant static flag on enum (Sonar)",
+  "change" : "Removed redundant static flag on enum",
+  "references" : [
+    "https://sonarsource.github.io/rspec/#/rspec/S2786/java"
+  ]
+}

core-codemods/src/test/java/io/codemodder/codemods/FixRedundantStaticOnEnumCodemodTest.java

@@ -0,0 +1,10 @@
+package io.codemodder.codemods;
+
+import io.codemodder.testutils.CodemodTestMixin;
+import io.codemodder.testutils.Metadata;
+
+@Metadata(
+    codemodType = FixRedundantStaticOnEnumCodemod.class,
+    testResourceDir = "remove-redundant-static-s2786",
+    dependencies = {})
+final class FixRedundantStaticOnEnumCodemodTest implements CodemodTestMixin {}

core-codemods/src/test/resources/remove-redundant-static-s2786/Test.java.after

@@ -0,0 +1,7 @@
+package acme.test;
+
+public class Response {
+  enum Status {
+    SUCCESS, FAILURE, ERROR
+  }
+}

core-codemods/src/test/resources/remove-redundant-static-s2786/Test.java.before

@@ -0,0 +1,7 @@
+package acme.test;
+
+public class Response {
+  static enum Status {
+    SUCCESS, FAILURE, ERROR
+  }
+}

core-codemods/src/test/resources/remove-redundant-static-s2786/sonar-issues.json

@@ -0,0 +1,93 @@
+{
+  "total": 1,
+  "p": 1,
+  "ps": 500,
+  "paging": {
+    "pageIndex": 1,
+    "pageSize": 500,
+    "total": 1
+  },
+  "effortTotal": 2,
+  "debtTotal": 2,
+  "issues": [
+    {
+      "key": "AYv0acY3pMuQdcUNcsKX",
+      "rule": "java:S2786",
+      "severity": "MINOR",
+      "component": "nahsra_WebGoat_10_23:Test.java",
+      "project": "nahsra_WebGoat_10_23",
+      "line": 4,
+      "hash": "f7cdce57b37926f1061e0ab664b60dbd",
+      "textRange": {
+        "startLine": 4,
+        "endLine": 4,
+        "startOffset": 2,
+        "endOffset": 8
+      },
+      "flows": [
+        {
+          "locations": [
+            {
+              "component": "nahsra_WebGoat_10_23:Test.java",
+              "textRange": {
+                "startLine": 4,
+                "endLine": 4,
+                "startOffset": 9,
+                "endOffset": 13
+              }
+            }
+          ]
+        }
+      ],
+      "status": "OPEN",
+      "message": "Remove this redundant \"static\" qualifier; nested enum types are implicitly static.",
+      "effort": "2min",
+      "debt": "2min",
+      "assignee": "nahsra@github",
+      "author": "[email protected]",
+      "tags": [
+        "redundant"
+      ],
+      "creationDate": "2023-11-22T01:21:06+0100",
+      "updateDate": "2023-11-22T01:21:29+0100",
+      "type": "CODE_SMELL",
+      "organization": "nahsra",
+      "cleanCodeAttribute": "CLEAR",
+      "cleanCodeAttributeCategory": "INTENTIONAL",
+      "impacts": [
+        {
+          "softwareQuality": "MAINTAINABILITY",
+          "severity": "LOW"
+        }
+      ]
+    }
+  ],
+  "components": [
+    {
+      "organization": "nahsra",
+      "key": "nahsra_WebGoat_10_23",
+      "uuid": "AYvtqxxxzY4Rr5NHn4Om",
+      "enabled": true,
+      "qualifier": "TRK",
+      "name": "WebGoat_10_23",
+      "longName": "WebGoat_10_23"
+    },
+    {
+      "organization": "nahsra",
+      "key": "nahsra_WebGoat_10_23:webgoat-lessons/vulnerable-components/src/main/java/org/owasp/webgoat/vulnerable_components/EnumThing.java",
+      "uuid": "AYv0abClpMuQdcUNcsKV",
+      "enabled": true,
+      "qualifier": "FIL",
+      "name": "EnumThing.java",
+      "longName": "webgoat-lessons/vulnerable-components/src/main/java/org/owasp/webgoat/vulnerable_components/EnumThing.java",
+      "path": "webgoat-lessons/vulnerable-components/src/main/java/org/owasp/webgoat/vulnerable_components/EnumThing.java"
+    }
+  ],
+  "organizations": [
+    {
+      "key": "nahsra",
+      "name": "Arshan Dabirsiaghi"
+    }
+  ],
+  "facets": []
+}