Version conflict exception message enhancement (#29432)

Report doc is not found rather on PUT ?version=X rather current version [-1] is different than the one provided

Closes #21278

server/src/main/java/org/elasticsearch/index/VersionType.java

@@ -38,6 +38,9 @@ public enum VersionType implements Writeable {
             if (expectedVersion == Versions.MATCH_DELETED) {
                 return "document already exists (current version [" + currentVersion + "])";
             }
+            if (currentVersion == Versions.NOT_FOUND) {
+                return "document does not exist (expected version [" + expectedVersion + "])";
+            }
             return "current version [" + currentVersion + "] is different than the one provided [" + expectedVersion + "]";
         }
 
@@ -48,6 +51,9 @@ public enum VersionType implements Writeable {
 
         @Override
         public String explainConflictForReads(long currentVersion, long expectedVersion) {
+            if (currentVersion == Versions.NOT_FOUND) {
+                return "document does not exist (expected version [" + expectedVersion + "])";
+            }
             return "current version [" + currentVersion + "] is different than the one provided [" + expectedVersion + "]";
         }
 
@@ -123,6 +129,9 @@ public enum VersionType implements Writeable {
 
         @Override
         public String explainConflictForReads(long currentVersion, long expectedVersion) {
+            if (currentVersion == Versions.NOT_FOUND) {
+                return "document does not exist (expected version [" + expectedVersion + "])";
+            }
             return "current version [" + currentVersion + "] is different than the one provided [" + expectedVersion + "]";
         }
 
@@ -178,6 +187,9 @@ public enum VersionType implements Writeable {
 
         @Override
         public String explainConflictForReads(long currentVersion, long expectedVersion) {
+            if (currentVersion == Versions.NOT_FOUND) {
+                return "document does not exist (expected version [" + expectedVersion + "])";
+            }
             return "current version [" + currentVersion + "] is different than the one provided [" + expectedVersion + "]";
         }
 

server/src/test/java/org/elasticsearch/index/VersionTypeTests.java

@@ -35,6 +35,11 @@ public class VersionTypeTests extends ESTestCase {
         assertFalse(VersionType.INTERNAL.isVersionConflictForWrites(Versions.NOT_FOUND, Versions.MATCH_ANY, randomBoolean()));
         assertFalse(VersionType.INTERNAL.isVersionConflictForReads(Versions.NOT_FOUND, Versions.MATCH_ANY));
 
+        assertEquals("current version [1] is different than the one provided [2]",
+            VersionType.INTERNAL.explainConflictForReads(1, 2));
+        assertEquals("document does not exist (expected version [2])",
+            VersionType.INTERNAL.explainConflictForReads(Versions.NOT_FOUND, 2));
+
         // deletes
         assertFalse(VersionType.INTERNAL.isVersionConflictForWrites(Versions.NOT_FOUND, Versions.MATCH_DELETED, true));
         assertFalse(VersionType.INTERNAL.isVersionConflictForWrites(10, Versions.MATCH_DELETED, true));
@@ -70,6 +75,11 @@ public class VersionTypeTests extends ESTestCase {
         assertTrue(VersionType.EXTERNAL.validateVersionForReads(randomIntBetween(1, Integer.MAX_VALUE)));
         assertFalse(VersionType.EXTERNAL.validateVersionForReads(randomIntBetween(Integer.MIN_VALUE, -1)));
 
+        assertEquals("current version [1] is different than the one provided [2]",
+            VersionType.EXTERNAL.explainConflictForReads(1, 2));
+        assertEquals("document does not exist (expected version [2])",
+            VersionType.EXTERNAL.explainConflictForReads(Versions.NOT_FOUND, 2));
+
         assertTrue(VersionType.EXTERNAL_GTE.validateVersionForWrites(randomIntBetween(1, Integer.MAX_VALUE)));
         assertFalse(VersionType.EXTERNAL_GTE.validateVersionForWrites(Versions.MATCH_ANY));
         assertFalse(VersionType.EXTERNAL_GTE.validateVersionForWrites(randomIntBetween(Integer.MIN_VALUE, 0)));
@@ -77,6 +87,11 @@ public class VersionTypeTests extends ESTestCase {
         assertTrue(VersionType.EXTERNAL_GTE.validateVersionForReads(randomIntBetween(1, Integer.MAX_VALUE)));
         assertFalse(VersionType.EXTERNAL_GTE.validateVersionForReads(randomIntBetween(Integer.MIN_VALUE, -1)));
 
+        assertEquals("current version [1] is different than the one provided [2]",
+            VersionType.EXTERNAL_GTE.explainConflictForReads(1, 2));
+        assertEquals("document does not exist (expected version [2])",
+            VersionType.EXTERNAL_GTE.explainConflictForReads(Versions.NOT_FOUND, 2));
+
         assertTrue(VersionType.INTERNAL.validateVersionForWrites(randomIntBetween(1, Integer.MAX_VALUE)));
         assertTrue(VersionType.INTERNAL.validateVersionForWrites(Versions.MATCH_ANY));
         assertFalse(VersionType.INTERNAL.validateVersionForWrites(randomIntBetween(Integer.MIN_VALUE, 0)));