SONARJAVA-6102 : Relax rule S8847 to avoid raising too many FPs

its/autoscan/src/test/java/org/sonar/java/it/AutoScanTest.java

@@ -199,7 +199,7 @@ public void javaCheckTestSources() throws Exception {
     softly.assertThat(newDiffs).containsExactlyInAnyOrderElementsOf(knownDiffs.values());
     softly.assertThat(newTotal).isEqualTo(knownTotal);
     softly.assertThat(rulesCausingFPs).hasSize(10);
-    softly.assertThat(rulesNotReporting).hasSize(18);
+    softly.assertThat(rulesNotReporting).hasSize(19);
 
     /**
      * 4. Check total number of differences (FPs + FNs)

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

@@ -2881,7 +2881,7 @@
   },
   {
     "ruleKey": "8447",
-    "hasTruePositives": true,
+    "hasTruePositives": false,
     "falseNegatives": 0,
     "falsePositives": 0
   },

its/autoscan/src/test/resources/autoscan/diffs/diff_S8447.json

@@ -1,6 +1,6 @@
 {
   "ruleKey": "S8447",
-  "hasTruePositives": true,
+  "hasTruePositives": false,
   "falseNegatives": 0,
   "falsePositives": 0
 }

java-checks-test-sources/default/src/main/files/non-compiling/checks/InitializeSubclassFieldsBeforeSuperSample.java

@@ -173,22 +173,11 @@ abstract class Middle extends Base {
 
       Middle() {
         super();
-        this.label = "value"; // Noncompliant
+        this.label = "value"; // Compliant : cannot resolve describe() implementation, conservative approach is to not flag
       }
 
       abstract void describe();
     }
-
-    abstract class Leaf extends Middle {
-      Leaf() {
-        super();
-      }
-
-      @Override
-      void describe() {
-        IO.println(label);
-      }
-    }
   }
 
   // Parameter with same name as field: bare name resolves to parameter, this.field resolves to field

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

@@ -79,8 +79,8 @@ private static boolean isFieldUsedInMethod(
   ) {
     BlockTree methodBlock;
     if (method == null || (methodBlock = method.block()) == null) {
-      // Can't resolve body, conservatively assume field may be used.
-      return true;
+      // Can't resolve body, assume field is not used to avoid false positives
+      return false;
     }
     SymbolUsedVisitor symbolUsedVisitor = new SymbolUsedVisitor(symbol, childClass, visitedMethods);
     methodBlock.body().forEach(statement -> statement.accept(symbolUsedVisitor));