revert to KEP compatible way

Signed-off-by: Attila Mészáros <[email protected]>

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/PrimaryUpdateAndCacheUtils.java

@@ -453,23 +453,53 @@ public static <P extends HasMetadata> P addFinalizerWithSSA(
 
   public static int compareResourceVersions(String v1, String v2) {
     var v1Length = v1.length();
-    var v2Length = v2.length();
-    if (v1Length > v2Length) {
-      return 1;
+    if (v1Length == 0) {
+      throw new IllegalArgumentException("Resource version (1) is empty");
     }
-    if (v1Length < v2Length) {
-      return -1;
+    var v2Length = v2.length();
+    if (v2Length == 0) {
+      throw new IllegalArgumentException("Resource version (2) is empty");
     }
-    for (int i = 0; i < v1Length; i++) {
-      var char1 = v1.charAt(i);
-      var char2 = v2.charAt(i);
-      if (char1 > char2) {
-        return 1;
+    var maxLength = Math.max(v1Length, v2Length);
+    boolean v1LeadingZero = true;
+    boolean v2LeadingZero = true;
+    int comparison = 0;
+    for (int i = 0; i < maxLength; i++) {
+      char char1 = 0;
+      if (i < v1Length) {
+        char1 = v1.charAt(i);
+        if (v1LeadingZero) {
+          if (char1 == '0') {
+            throw new IllegalArgumentException("Resource version (1) cannot begin with 0");
+          }
+          v1LeadingZero = false;
+        }
+        if (!Character.isDigit(char1)) {
+          throw new IllegalArgumentException(
+              "Non numeric characters in resource version (1): " + char1);
+        }
       }
-      if (char1 < char2) {
-        return -1;
+      if (i < v2Length) {
+        var char2 = v2.charAt(i);
+        if (v2LeadingZero) {
+          if (char2 == '0') {
+            throw new IllegalArgumentException("Resource version (2) cannot begin with 0");
+          }
+          v2LeadingZero = false;
+        }
+        if (!Character.isDigit(char2)) {
+          throw new IllegalArgumentException(
+              "Non numeric characters in resource version (2): " + char2);
+        }
+        if (char1 == 0) {
+          comparison = -1;
+        } else if (comparison == 0) {
+          comparison = Character.compare(char1, char2);
+        }
+      } else {
+        comparison = 1;
       }
     }
-    return 0;
+    return comparison;
   }
 }

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/api/reconciler/PrimaryUpdateAndCacheUtilsTest.java

@@ -190,12 +190,19 @@ public void compareResourceVersionsTest() {
 
     assertThat(compareResourceVersions("123", "2")).isPositive();
     assertThat(compareResourceVersions("3", "211")).isNegative();
+
+    assertThrows(IllegalArgumentException.class, () -> compareResourceVersions("aa", "22"));
+    assertThrows(IllegalArgumentException.class, () -> compareResourceVersions("11", "ba"));
+    assertThrows(IllegalArgumentException.class, () -> compareResourceVersions("", "22"));
+    assertThrows(IllegalArgumentException.class, () -> compareResourceVersions("11", ""));
+    assertThrows(IllegalArgumentException.class, () -> compareResourceVersions("01", "123"));
+    assertThrows(IllegalArgumentException.class, () -> compareResourceVersions("123", "01"));
   }
 
   // naive performance that compares the works case scenario for non parsing variant
   @Test
   public void compareResourcePerformanceTest() {
-    var execNum = 20000000;
+    var execNum = 30000000;
     var startTime = System.currentTimeMillis();
     for (int i = 0; i < execNum; i++) {
       var res = compareResourceVersions("123456788", "123456789");