Only throw exception for id and cas not projected if needed.

src/main/java/org/springframework/data/couchbase/core/CouchbaseTemplateSupport.java

@@ -37,6 +37,7 @@
 import org.springframework.data.couchbase.core.mapping.event.BeforeConvertEvent;
 import org.springframework.data.couchbase.core.mapping.event.BeforeSaveEvent;
 import org.springframework.data.couchbase.core.mapping.event.CouchbaseMappingEvent;
+import org.springframework.data.couchbase.core.support.TemplateUtils;
 import org.springframework.data.couchbase.repository.support.MappingCouchbaseEntityInformation;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
 import org.springframework.data.mapping.callback.EntityCallbacks;
@@ -45,6 +46,8 @@
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
+import com.couchbase.client.core.error.CouchbaseException;
+
 /**
  * Internal encode/decode support for CouchbaseTemplate.
  *
@@ -85,9 +88,7 @@ public CouchbaseDocument encodeEntity(final Object entityToEncode) {
 	}
 
 	@Override
-	public <T> T decodeEntity(String id, String source, long cas, Class<T> entityClass, String scope, String collection) {
-		final CouchbaseDocument converted = new CouchbaseDocument(id);
-		converted.setId(id);
+	public <T> T decodeEntity(String id, String source, Long cas, Class<T> entityClass, String scope, String collection) {
 
 		// this is the entity class defined for the repository. It may not be the class of the document that was read
 		// we will reset it after reading the document
@@ -107,18 +108,32 @@ public <T> T decodeEntity(String id, String source, long cas, Class<T> entityCla
 			// to unwrap. This results in List<String[]> being unwrapped past String[] to String, so this may also be a
 			// Collection (or Array) of entityClass. We have no way of knowing - so just assume it is what we are told.
 			// if this is a Collection or array, only the first element will be returned.
+			final CouchbaseDocument converted = new CouchbaseDocument(id);
 			Set<Map.Entry<String, Object>> set = ((CouchbaseDocument) translationService.decode(source, converted))
 					.getContent().entrySet();
 			return (T) set.iterator().next().getValue();
 		}
 
+		if (id == null) {
+			throw new CouchbaseException(TemplateUtils.SELECT_ID + " was null. Either use #{#n1ql.selectEntity} or project "
+					+ TemplateUtils.SELECT_ID);
+		}
+
+		final CouchbaseDocument converted = new CouchbaseDocument(id);
+
 		// if possible, set the version property in the source so that if the constructor has a long version argument,
-		// it will have a value an not fail (as null is not a valid argument for a long argument). This possible failure
+		// it will have a value and not fail (as null is not a valid argument for a long argument). This possible failure
 		// can be avoid by defining the argument as Long instead of long.
 		// persistentEntity is still the (possibly abstract) class specified in the repository definition
 		// it's possible that the abstract class does not have a version property, and this won't be able to set the version
-		if (cas != 0 && persistentEntity.getVersionProperty() != null) {
-			converted.put(persistentEntity.getVersionProperty().getName(), cas);
+		if (persistentEntity.getVersionProperty() != null) {
+			if (cas == null) {
+				throw new CouchbaseException("version/cas in the entity but " + TemplateUtils.SELECT_CAS
+						+ " was not in result. Either use #{#n1ql.selectEntity} or project " + TemplateUtils.SELECT_CAS);
+			}
+			if (cas != 0) {
+				converted.put(persistentEntity.getVersionProperty().getName(), cas);
+			}
 		}
 
 		// if the constructor has an argument that is long version, then construction will fail if the 'version'

src/main/java/org/springframework/data/couchbase/core/NonReactiveSupportWrapper.java

@@ -40,7 +40,7 @@ public Mono<CouchbaseDocument> encodeEntity(Object entityToEncode) {
 	}
 
 	@Override
-	public <T> Mono<T> decodeEntity(String id, String source, long cas, Class<T> entityClass, String scope,
+	public <T> Mono<T> decodeEntity(String id, String source, Long cas, Class<T> entityClass, String scope,
 			String collection) {
 		return Mono.fromSupplier(() -> support.decodeEntity(id, source, cas, entityClass, scope, collection));
 	}

src/main/java/org/springframework/data/couchbase/core/ReactiveCouchbaseTemplateSupport.java

@@ -85,7 +85,7 @@ public Mono<CouchbaseDocument> encodeEntity(final Object entityToEncode) {
 	}
 
 	@Override
-	public <T> Mono<T> decodeEntity(String id, String source, long cas, Class<T> entityClass, String scope,
+	public <T> Mono<T> decodeEntity(String id, String source, Long cas, Class<T> entityClass, String scope,
 			String collection) {
 		return Mono.fromSupplier(() -> {
 			final CouchbaseDocument converted = new CouchbaseDocument(id);

src/main/java/org/springframework/data/couchbase/core/ReactiveFindByAnalyticsOperationSupport.java

@@ -22,7 +22,6 @@
 import org.springframework.data.couchbase.core.support.TemplateUtils;
 import org.springframework.util.Assert;
 
-import com.couchbase.client.core.error.CouchbaseException;
 import com.couchbase.client.java.analytics.AnalyticsOptions;
 import com.couchbase.client.java.analytics.AnalyticsScanConsistency;
 import com.couchbase.client.java.analytics.ReactiveAnalyticsResult;
@@ -117,23 +116,13 @@ public Flux<T> all() {
 								return throwable;
 							}
 						}).flatMapMany(ReactiveAnalyticsResult::rowsAsObject).flatMap(row -> {
-							String id = "";
-							Long cas = Long.valueOf(0);
-							if (row.getString(TemplateUtils.SELECT_ID) == null && row.getString(TemplateUtils.SELECT_ID_3x) == null) {
-								return Flux.error(new CouchbaseException("analytics query did not project " + TemplateUtils.SELECT_ID
-										+ ". Either use #{#n1ql.selectEntity} or project " + TemplateUtils.SELECT_ID + " and "
-										+ TemplateUtils.SELECT_CAS + " : " + statement));
-							}
+							String id = null;
+							Long cas = null;
 							id = row.getString(TemplateUtils.SELECT_ID);
 							if (id == null) {
 								id = row.getString(TemplateUtils.SELECT_ID_3x);
 								row.removeKey(TemplateUtils.SELECT_ID_3x);
 							}
-							if (row.getLong(TemplateUtils.SELECT_CAS) == null && row.getLong(TemplateUtils.SELECT_CAS_3x) == null) {
-								return Flux.error(new CouchbaseException("analytics query did not project " + TemplateUtils.SELECT_CAS
-										+ ". Either use #{#n1ql.selectEntity} or project " + TemplateUtils.SELECT_ID + " and "
-										+ TemplateUtils.SELECT_CAS + " : " + statement));
-							}
 							cas = row.getLong(TemplateUtils.SELECT_CAS);
 							if (cas == null) {
 								cas = row.getLong(TemplateUtils.SELECT_CAS_3x);

src/main/java/org/springframework/data/couchbase/core/ReactiveFindByQueryOperationSupport.java

@@ -25,7 +25,6 @@
 import org.springframework.data.couchbase.core.support.TemplateUtils;
 import org.springframework.util.Assert;
 
-import com.couchbase.client.core.error.CouchbaseException;
 import com.couchbase.client.java.query.QueryOptions;
 import com.couchbase.client.java.query.QueryScanConsistency;
 import com.couchbase.client.java.query.ReactiveQueryResult;
@@ -184,24 +183,17 @@ public Flux<T> all() {
 					return throwable;
 				}
 			}).flatMapMany(ReactiveQueryResult::rowsAsObject).flatMap(row -> {
-				String id = "";
-				Long cas = Long.valueOf(0);
-				if (!query.isDistinct() && distinctFields == null) {
-					if (row.getString(TemplateUtils.SELECT_ID) == null && row.getString(TemplateUtils.SELECT_ID_3x) == null) {
-						return Flux.error(new CouchbaseException(
-								"query did not project " + TemplateUtils.SELECT_ID + ". Either use #{#n1ql.selectEntity} or project "
-										+ TemplateUtils.SELECT_ID + " and " + TemplateUtils.SELECT_CAS + " : " + statement));
-					}
+				String id = null;
+				Long cas = null;
+				if (query.isDistinct() || distinctFields != null) {
+					id = "";
+					cas = Long.valueOf(0);
+				} else {
 					id = row.getString(TemplateUtils.SELECT_ID);
 					if (id == null) {
 						id = row.getString(TemplateUtils.SELECT_ID_3x);
 						row.removeKey(TemplateUtils.SELECT_ID_3x);
 					}
-					if (row.getLong(TemplateUtils.SELECT_CAS) == null && row.getLong(TemplateUtils.SELECT_CAS_3x) == null) {
-						return Flux.error(new CouchbaseException(
-								"query did not project " + TemplateUtils.SELECT_CAS + ". Either use #{#n1ql.selectEntity} or project "
-										+ TemplateUtils.SELECT_ID + " and " + TemplateUtils.SELECT_CAS + " : " + statement));
-					}
 					cas = row.getLong(TemplateUtils.SELECT_CAS);
 					if (cas == null) {
 						cas = row.getLong(TemplateUtils.SELECT_CAS_3x);

src/main/java/org/springframework/data/couchbase/core/ReactiveTemplateSupport.java

@@ -21,14 +21,13 @@
 import org.springframework.data.couchbase.core.mapping.event.CouchbaseMappingEvent;
 
 /**
- *
  * @author Michael Reiche
  */
 public interface ReactiveTemplateSupport {
 
 	Mono<CouchbaseDocument> encodeEntity(Object entityToEncode);
 
-	<T> Mono<T> decodeEntity(String id, String source, long cas, Class<T> entityClass, String scope, String collection);
+	<T> Mono<T> decodeEntity(String id, String source, Long cas, Class<T> entityClass, String scope, String collection);
 
 	<T> Mono<T> applyUpdatedCas(T entity, CouchbaseDocument converted, long cas);
 

src/main/java/org/springframework/data/couchbase/core/TemplateSupport.java

@@ -26,7 +26,7 @@ public interface TemplateSupport {
 
 	CouchbaseDocument encodeEntity(Object entityToEncode);
 
-	<T> T decodeEntity(String id, String source, long cas, Class<T> entityClass, String scope, String collection);
+	<T> T decodeEntity(String id, String source, Long cas, Class<T> entityClass, String scope, String collection);
 
 	<T> T applyUpdatedCas(T entity, CouchbaseDocument converted, long cas);