fix: Concurrent modification exception during the datasource import flow

app/server/appsmith-server/src/main/java/com/appsmith/server/datasources/base/DatasourceServiceCE.java

@@ -6,6 +6,7 @@
 import com.appsmith.external.models.DatasourceTestResult;
 import com.appsmith.external.models.MustacheBindingToken;
 import com.appsmith.server.acl.AclPermission;
+import com.appsmith.server.dtos.DBOpsType;
 import org.springframework.util.MultiValueMap;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -67,7 +68,7 @@ public interface DatasourceServiceCE {
     Mono<Datasource> createWithoutPermissions(Datasource datasource);
 
     Mono<Datasource> createWithoutPermissions(
-            Datasource datasource, Map<String, List<DatasourceStorage>> datasourceStorageDryRunQueries);
+            Datasource datasource, Map<DBOpsType, List<DatasourceStorage>> datasourceStorageDryRunQueries);
 
     Mono<Datasource> updateDatasourceStorage(
             DatasourceStorageDTO datasourceStorageDTO, String activeEnvironmentId, Boolean IsUserRefreshedUpdate);

app/server/appsmith-server/src/main/java/com/appsmith/server/datasources/base/DatasourceServiceCEImpl.java

@@ -64,6 +64,7 @@
 import static com.appsmith.external.constants.spans.DatasourceSpan.FETCH_ALL_DATASOURCES_WITH_STORAGES;
 import static com.appsmith.external.constants.spans.DatasourceSpan.FETCH_ALL_PLUGINS_IN_WORKSPACE;
 import static com.appsmith.external.helpers.AppsmithBeanUtils.copyNestedNonNullProperties;
+import static com.appsmith.server.dtos.DBOpsType.SAVE;
 import static com.appsmith.server.helpers.CollectionUtils.isNullOrEmpty;
 import static com.appsmith.server.helpers.DatasourceAnalyticsUtils.getAnalyticsProperties;
 import static com.appsmith.server.helpers.DatasourceAnalyticsUtils.getAnalyticsPropertiesForTestEventStatus;
@@ -147,7 +148,7 @@ public Mono<Datasource> create(Datasource datasource) {
     // TODO: Check usage
     @Override
     public Mono<Datasource> createWithoutPermissions(
-            Datasource datasource, Map<String, List<DatasourceStorage>> datasourceStorageDryRunQueries) {
+            Datasource datasource, Map<DBOpsType, List<DatasourceStorage>> datasourceStorageDryRunQueries) {
         return createEx(datasource, null, true, datasourceStorageDryRunQueries);
     }
 
@@ -160,7 +161,7 @@ private Mono<Datasource> createEx(
             @NotNull Datasource datasource,
             AclPermission permission,
             boolean isDryOps,
-            Map<String, List<DatasourceStorage>> datasourceStorageDryRunQueries) {
+            Map<DBOpsType, List<DatasourceStorage>> datasourceStorageDryRunQueries) {
         // Validate incoming request
         String workspaceId = datasource.getWorkspaceId();
         if (!hasText(workspaceId)) {
@@ -232,9 +233,13 @@ private Mono<Datasource> createEx(
                             .create(datasourceStorage, isDryOps)
                             .map(datasourceStorage1 -> {
                                 if (datasourceStorageDryRunQueries != null && isDryOps) {
-                                    datasourceStorageDryRunQueries
-                                            .computeIfAbsent(DBOpsType.SAVE.name(), k -> new ArrayList<>())
-                                            .add(datasourceStorage1);
+                                    List<DatasourceStorage> datasourceStorages =
+                                            datasourceStorageDryRunQueries.get(SAVE);
+                                    if (datasourceStorages == null) {
+                                        datasourceStorages = new ArrayList<>();
+                                    }
+                                    datasourceStorages.add(datasourceStorage1);
+                                    datasourceStorageDryRunQueries.put(SAVE, datasourceStorages);
                                 }
                                 return datasourceStorage1;
                             });

app/server/appsmith-server/src/main/java/com/appsmith/server/datasources/importable/DatasourceImportableServiceCEImpl.java

@@ -25,6 +25,7 @@
 import com.appsmith.server.imports.importable.artifactbased.ArtifactBasedImportableService;
 import com.appsmith.server.services.SequenceService;
 import com.appsmith.server.services.WorkspaceService;
+import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.collections.CollectionUtils;
 import org.apache.commons.lang3.StringUtils;
@@ -408,7 +409,10 @@ public Flux<Datasource> getEntitiesPresentInWorkspace(String workspaceId) {
     }
 
     private void addDryOpsForEntity(
-            DBOpsType queryType, Map<String, List<Datasource>> dryRunOpsMap, Datasource createdDatasource) {
-        dryRunOpsMap.computeIfAbsent(queryType.name(), k -> new ArrayList<>()).add(createdDatasource);
+            DBOpsType queryType, @NonNull Map<DBOpsType, List<Datasource>> dryRunOpsMap, Datasource createdDatasource) {
+        List<Datasource> datasourceList = dryRunOpsMap.get(queryType);
+        datasourceList = datasourceList == null ? new ArrayList<>() : datasourceList;
+        datasourceList.add(createdDatasource);
+        dryRunOpsMap.put(queryType, datasourceList);
     }
 }

app/server/appsmith-server/src/main/java/com/appsmith/server/dtos/ce/MappedImportableResourcesCE_DTO.java

@@ -5,12 +5,15 @@
 import com.appsmith.server.domains.Context;
 import com.appsmith.server.domains.CustomJSLib;
 import com.appsmith.server.dtos.CustomJSLibContextDTO;
+import com.appsmith.server.dtos.DBOpsType;
 import com.appsmith.server.dtos.ImportActionCollectionResultDTO;
 import com.appsmith.server.dtos.ImportActionResultDTO;
 import com.appsmith.server.dtos.ImportedActionAndCollectionMapsDTO;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -48,9 +51,24 @@ public class MappedImportableResourcesCE_DTO {
     Map<String, Object> resourceStoreFromArtifactExchangeJson = new HashMap<>();
 
     // Dry ops queries
-    Map<String, List<Datasource>> datasourceDryRunQueries = new HashMap<>();
+    Map<DBOpsType, List<Datasource>> datasourceDryRunQueries = new HashMap<>();
 
-    Map<String, List<DatasourceStorage>> datasourceStorageDryRunQueries = new HashMap<>();
+    Map<DBOpsType, List<DatasourceStorage>> datasourceStorageDryRunQueries = new HashMap<>();
 
     Map<String, List<CustomJSLib>> customJSLibsDryOps = new HashMap<>();
+
+    {
+        for (DBOpsType dbOpsType : DBOpsType.values()) {
+            /**
+             * Using Collections.synchronizedList() ensures that the list itself is synchronized, meaning that
+             * individual operations on the list are thread-safe. This includes operations such as adding, removing,
+             * or accessing elements. However, this does not protect against compound operations, such as checking if
+             * an element exists and then adding it based on that check. For these compound operations, we would
+             * need additional synchronization using synchronized blocks.
+             * Ref: https://blog.codingblocks.com/2019/keeping-arraylists-safe-across-threads-in-java/
+             */
+            datasourceStorageDryRunQueries.put(dbOpsType, Collections.synchronizedList(new ArrayList<>()));
+            datasourceDryRunQueries.put(dbOpsType, Collections.synchronizedList(new ArrayList<>()));
+        }
+    }
 }

app/server/appsmith-server/src/test/java/com/appsmith/server/imports/internal/ImportServiceTests.java

@@ -1569,6 +1569,8 @@ public void importApplication_withUnConfiguredDatasources_Success() {
                 .verifyComplete();
     }
 
+    @Test
+    @WithUserDetails(value = "api_user")
     public void importArtifactIntoWorkspace_pageRemovedAndUpdatedDefaultPageNameInBranchApplication_Success() {
         Application testApplication = new Application();
         testApplication.setName("importApplicationIntoWorkspace_pageRemovedInBranchApplication_Success");