SONARJAVA-5759 Fix NPE on S3457 on enums declaration type (#5293)

Author: leonardo-pilastri-sonarsource

its/autoscan/src/test/resources/autoscan/autoscan-diff-by-rules.json

@@ -1598,7 +1598,7 @@
   {
     "ruleKey": "S3457",
     "hasTruePositives": true,
-    "falseNegatives": 150,
+    "falseNegatives": 152,
     "falsePositives": 0
   },
   {

its/autoscan/src/test/resources/autoscan/diffs/diff_S3457.json

@@ -1,6 +1,6 @@
 {
   "ruleKey": "S3457",
   "hasTruePositives": true,
-  "falseNegatives": 150,
+  "falseNegatives": 152,
   "falsePositives": 0
-}
+}

java-checks-test-sources/default/src/main/java/checks/PrintfMisuseCheckEnumsSample.java

@@ -0,0 +1,25 @@
+package checks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+// Introduced to handle NPE described in SONARJAVA-5759
+// https://sonarsource.atlassian.net/browse/SONARJAVA-5759
+enum PrintfMisuseCheckEnumsSample {
+  A,
+  B;
+
+  private static final Logger LOG = LoggerFactory.getLogger(PrintfMisuseCheckEnumsSample.class);
+
+  public static PrintfMisuseCheckEnumsSample of(String name) {
+    if (name.equals(B.name())) {
+      LOG.error("Connector type name {}"); // Noncompliant
+      return B;
+    }
+    if (name.equals(A.name())) {
+      LOG.error("No action needed, just FYI: connector type name {}, or {}", A); // Noncompliant
+      return A;
+    }
+    return valueOf(name);
+  }
+}

java-checks/src/main/java/org/sonar/java/checks/PrintfMisuseCheck.java

@@ -302,7 +302,7 @@ private static boolean hasUnknownExceptionInUnionType(ExpressionTree lastArgumen
     }
     Symbol symbol = ((IdentifierTree) lastArgument).symbol();
     VariableTree declaration = symbol.isVariableSymbol() ? ((Symbol.VariableSymbol) symbol).declaration() : null;
-    if (declaration == null) {
+    if (declaration == null || declaration.type() == null) {
       return false;
     }
     TypeTree declarationType = declaration.type();

java-checks/src/test/java/org/sonar/java/checks/PrintfMisuseCheckTest.java

@@ -47,4 +47,13 @@ void test_unknown_union_types() {
       .withCheck(new PrintfMisuseCheck())
       .verifyIssues();
   }
+
+  @Test
+  void test_enums() {
+    // see SONARJAVA-5759
+    CheckVerifier.newVerifier()
+      .onFile(mainCodeSourcesPath("checks/PrintfMisuseCheckEnumsSample.java"))
+      .withCheck(new PrintfMisuseCheck())
+      .verifyIssues();
+  }
 }