SONAR-12078 out of memory in CE if file has too many issues

sonar-core/src/main/java/org/sonar/core/issue/tracking/BlockRecognizer.java

@@ -77,7 +77,7 @@ class BlockRecognizer<RAW extends Trackable, BASE extends Trackable> {
     }
 
     // Check if remaining number of lines exceeds threshold. It avoids processing too many combinations.
-    if (basesByLine.keySet().size() * rawsByLine.keySet().size() >= 250_000) {
+    if (isOverLimit(basesByLine.keySet().size(), rawsByLine.keySet().size())) {
       return;
     }
 
@@ -97,6 +97,10 @@ class BlockRecognizer<RAW extends Trackable, BASE extends Trackable> {
     }
   }
 
+  static boolean isOverLimit(long a, long b) {
+    return Math.multiplyExact(a, b) >= 250_000;
+  }
+
   /**
    * @param startLineA number of line from first version of text (numbering starts from 1)
    * @param startLineB number of line from second version of text (numbering starts from 1)

sonar-core/src/test/java/org/sonar/core/issue/tracking/BlockRecognizerTest.java

@@ -41,6 +41,15 @@ public class BlockRecognizerTest {
     assertThat(compute(seq("bcde"), seq("abcde"), 3, 4)).isEqualTo(4);
   }
 
+  @Test
+  public void isOverLimit() {
+    assertThat(BlockRecognizer.isOverLimit(20, 40)).isFalse();
+    assertThat(BlockRecognizer.isOverLimit(3, 100_000)).isTrue();
+
+    // multiplication of these two ints is higher than Integer.MAX_VALUE
+    assertThat(BlockRecognizer.isOverLimit(50_000, 60_000)).isTrue();
+  }
+
   private int compute(LineHashSequence seqA, LineHashSequence seqB, int ai, int bi) {
     return BlockRecognizer.lengthOfMaximalBlock(seqA, ai, seqB, bi);
   }