fix: Import from file fails when workspace has a git connected app wi… (#28299)

## Description
Fixes the bug when import app from file fails when target workspace has
existing app with same name and multiple branches.

#### PR fixes following issue(s)
Fixes #28122

#### Media
https://www.loom.com/share/5d31f58574f5422ba078e4153e39bf8c

#### Type of change
- Bug fix (non-breaking change which fixes an issue)

## Testing
#### How Has This Been Tested?
- [x] Manual
- [x] JUnit

#### Test Plan
#### Issues raised during DP testing

## Checklist:
#### Dev activity
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] PR is being merged under a feature flag


#### QA activity:
- [ ] [Speedbreak
features](https://github.com/appsmithorg/TestSmith/wiki/Guidelines-for-test-plans#speedbreakers-)
have been covered
- [ ] Test plan covers all impacted features and [areas of
interest](https://github.com/appsmithorg/TestSmith/wiki/Guidelines-for-test-plans#areas-of-interest-)
- [ ] Test plan has been peer reviewed by project stakeholders and other
QA members
- [ ] Manually tested functionality on DP
- [ ] We had an implementation alignment call with stakeholders post QA
Round 2
- [ ] Cypress test cases have been added and approved by SDET/manual QA
- [ ] Added `Test Plan Approved` label after Cypress tests were reviewed
- [ ] Added `Test Plan Approved` label after JUnit tests were reviewed

app/server/appsmith-server/src/main/java/com/appsmith/server/repositories/ce/CustomApplicationRepositoryCE.java

@@ -79,7 +79,7 @@ public interface CustomApplicationRepositoryCE extends AppsmithRepository<Applic
             String branchNamePath,
             AclPermission permission);
 
-    Mono<Application> findByNameAndWorkspaceId(String applicationName, String workspaceId, AclPermission permission);
+    Mono<Long> countByNameAndWorkspaceId(String applicationName, String workspaceId, AclPermission permission);
 
     Flux<String> getAllApplicationIdsInWorkspaceAccessibleToARoleWithPermission(
             String workspaceId, AclPermission permission, String permissionGroupId);

app/server/appsmith-server/src/main/java/com/appsmith/server/repositories/ce/CustomApplicationRepositoryCEImpl.java

@@ -318,13 +318,13 @@ public class CustomApplicationRepositoryCEImpl extends BaseAppsmithRepositoryImp
     }
 
     @Override
-    public Mono<Application> findByNameAndWorkspaceId(
-            String applicationName, String workspaceId, AclPermission permission) {
+    public Mono<Long> countByNameAndWorkspaceId(String applicationName, String workspaceId, AclPermission permission) {
         Criteria workspaceIdCriteria =
                 where(fieldName(QApplication.application.workspaceId)).is(workspaceId);
         Criteria applicationNameCriteria =
                 where(fieldName(QApplication.application.name)).is(applicationName);
-        return queryOne(List.of(workspaceIdCriteria, applicationNameCriteria), permission);
+
+        return count(List.of(workspaceIdCriteria, applicationNameCriteria), permission);
     }
 
     @Override

app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/ApplicationPageServiceCEImpl.java

@@ -1363,23 +1363,25 @@ public class ApplicationPageServiceCEImpl implements ApplicationPageServiceCE {
         Mono<User> userMono = sessionUserService.getCurrentUser().cache();
         Mono<Application> applicationWithPoliciesMono =
                 this.setApplicationPolicies(userMono, application.getWorkspaceId(), application);
-        Mono<Application> applicationMono = applicationService.findByNameAndWorkspaceId(
+        Mono<Boolean> applicationNameTakenMono = applicationService.isApplicationNameTaken(
                 actualName, application.getWorkspaceId(), MANAGE_APPLICATIONS);
 
         // We are taking pessimistic approach as this flow is used in import application where we are using transactions
         // which creates problem if we hit duplicate key exception
-        return applicationMono
-                .flatMap(application1 -> this.createOrUpdateSuffixedApplication(application, name, 1 + suffix))
-                .switchIfEmpty(Mono.defer(
-                        () -> applicationWithPoliciesMono.zipWith(userMono).flatMap(tuple -> {
-                            Application application1 = tuple.getT1();
-                            application1.setModifiedBy(
-                                    tuple.getT2().getUsername()); // setting modified by to current user
-                            // We can't use create or createApplication method here as we are expecting update operation
-                            // if the
-                            // _id is available with application object
-                            return applicationService.save(application);
-                        })));
+        return applicationNameTakenMono.flatMap(isNameTaken -> {
+            if (isNameTaken) {
+                return this.createOrUpdateSuffixedApplication(application, name, 1 + suffix);
+            } else {
+                return applicationWithPoliciesMono.zipWith(userMono).flatMap(tuple -> {
+                    Application application1 = tuple.getT1();
+                    application1.setModifiedBy(tuple.getT2().getUsername()); // setting modified by to current user
+                    // We can't use create or createApplication method here as we are expecting update operation
+                    // if the
+                    // _id is available with application object
+                    return applicationService.save(application);
+                });
+            }
+        });
     }
 
     /**

app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/ApplicationServiceCE.java

@@ -98,7 +98,7 @@ public interface ApplicationServiceCE extends CrudService<Application, String> {
 
     public Mono<Void> deleteAppNavigationLogo(String branchName, String applicationId);
 
-    Mono<Application> findByNameAndWorkspaceId(String applicationName, String workspaceId, AclPermission permission);
+    Mono<Boolean> isApplicationNameTaken(String applicationName, String workspaceId, AclPermission permission);
 
     Mono<Boolean> isApplicationConnectedToGit(String applicationId);
 }

app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/ApplicationServiceCEImpl.java

@@ -980,9 +980,10 @@ public class ApplicationServiceCEImpl extends BaseService<ApplicationRepository,
     }
 
     @Override
-    public Mono<Application> findByNameAndWorkspaceId(
-            String applicationName, String workspaceId, AclPermission permission) {
-        return repository.findByNameAndWorkspaceId(applicationName, workspaceId, permission);
+    public Mono<Boolean> isApplicationNameTaken(String applicationName, String workspaceId, AclPermission permission) {
+        return repository
+                .countByNameAndWorkspaceId(applicationName, workspaceId, permission)
+                .map(count -> count > 0);
     }
 
     @Override

app/server/appsmith-server/src/test/java/com/appsmith/server/services/ApplicationPageServiceTest.java

@@ -3,6 +3,7 @@ package com.appsmith.server.services;
 import com.appsmith.git.constants.CommonConstants;
 import com.appsmith.server.acl.AclPermission;
 import com.appsmith.server.domains.Application;
+import com.appsmith.server.domains.GitApplicationMetadata;
 import com.appsmith.server.domains.Layout;
 import com.appsmith.server.domains.NewPage;
 import com.appsmith.server.domains.Workspace;
@@ -287,4 +288,42 @@ public class ApplicationPageServiceTest {
                 })
                 .verifyComplete();
     }
+
+    @Test
+    @WithUserDetails("api_user")
+    public void createOrUpdateSuffixedApplication_GitConnectedAppExistsWithSameName_AppCreatedWithSuffixedName() {
+        // create a Git connected application with two branches
+        final String appName = "app" + UUID.randomUUID();
+        Application application = new Application();
+        application.setName(appName);
+        GitApplicationMetadata gitApplicationMetadata = new GitApplicationMetadata();
+        gitApplicationMetadata.setBranchName("branch1");
+        application.setGitApplicationMetadata(gitApplicationMetadata);
+
+        Mono<Application> importAppMono = applicationPageService
+                .createApplication(application, workspace.getId())
+                .flatMap(createdApp -> {
+                    createdApp.getGitApplicationMetadata().setDefaultApplicationId(createdApp.getId());
+                    return applicationService.save(createdApp);
+                })
+                .flatMap(createdApp -> {
+                    createdApp.setId(null);
+                    createdApp.getGitApplicationMetadata().setBranchName("branch2");
+                    // just duplicate the app, we're not considering the pages, they remain same in both apps
+                    return applicationRepository.save(createdApp);
+                })
+                .flatMap(createdApp -> {
+                    Application newApplication = new Application();
+                    newApplication.setName(appName);
+                    newApplication.setWorkspaceId(workspace.getId());
+                    return applicationPageService.createOrUpdateSuffixedApplication(
+                            newApplication, newApplication.getName(), 0);
+                });
+
+        StepVerifier.create(importAppMono)
+                .assertNext(application1 -> {
+                    assertThat(application1.getName()).isEqualTo(appName + " (1)");
+                })
+                .verifyComplete();
+    }
 }