Deprecate dataSource table with dual-write to workspace.databaseSchema (#19059)

## Summary
- Starts deprecation of the `core.dataSource` table by introducing a
dual-write system: `DataSourceService.createDataSourceMetadata` now
writes to both `core.dataSource` and `core.workspace.databaseSchema`
- Migrates read sites (`WorkspaceDataSourceService.checkSchemaExists`,
`WorkspaceSchemaFactory`, `MiddlewareService`,
`WorkspacesMigrationCommandRunner`) to read from
`workspace.databaseSchema` instead of querying the `dataSource` table
- Removes the unused `databaseUrl` field from `WorkspaceEntity` and
drops the column via migration
- Adds a 1.20 upgrade command to backfill `workspace.databaseSchema`
from `dataSource.schema` for existing workspaces

packages/twenty-server/src/engine/api/graphql/workspace-schema.factory.ts

@@ -1,14 +1,17 @@
 import { Injectable } from '@nestjs/common';
 
 import { makeExecutableSchema } from '@graphql-tools/schema';
+import { isNonEmptyString } from '@sniptt/guards';
 import { GraphQLSchema, printSchema } from 'graphql';
 import { gql } from 'graphql-tag';
+import { FeatureFlagKey } from 'twenty-shared/types';
 import { isDefined } from 'twenty-shared/utils';
 
 import { ScalarsExplorerService } from 'src/engine/api/graphql/services/scalars-explorer.service';
 import { workspaceResolverBuilderMethodNames } from 'src/engine/api/graphql/workspace-resolver-builder/factories/factories';
 import { WorkspaceResolverFactory } from 'src/engine/api/graphql/workspace-resolver-builder/workspace-resolver.factory';
 import { WorkspaceGraphQLSchemaGenerator } from 'src/engine/api/graphql/workspace-schema-builder/workspace-graphql-schema.factory';
+import { FeatureFlagService } from 'src/engine/core-modules/feature-flag/services/feature-flag.service';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
 import { DataSourceService } from 'src/engine/metadata-modules/data-source/data-source.service';
 import {
@@ -28,24 +31,33 @@ import { TWENTY_STANDARD_APPLICATION } from 'src/engine/workspace-manager/twenty
 @Injectable()
 export class WorkspaceSchemaFactory {
   constructor(
-    private readonly dataSourceService: DataSourceService,
     private readonly scalarsExplorerService: ScalarsExplorerService,
     private readonly workspaceGraphQLSchemaGenerator: WorkspaceGraphQLSchemaGenerator,
     private readonly workspaceResolverFactory: WorkspaceResolverFactory,
     private readonly workspaceCacheStorageService: WorkspaceCacheStorageService,
     private readonly workspaceManyOrAllFlatEntityMapsCacheService: WorkspaceManyOrAllFlatEntityMapsCacheService,
+    private readonly featureFlagService: FeatureFlagService,
+    private readonly dataSourceService: DataSourceService,
   ) {}
 
   async createGraphQLSchema(
     workspace: WorkspaceEntity,
     applicationId?: string,
   ): Promise<GraphQLSchema> {
-    const dataSourcesMetadata =
-      await this.dataSourceService.getDataSourcesMetadataFromWorkspaceId(
-        workspace.id,
-      );
+    const isDataSourceMigrated = await this.featureFlagService.isFeatureEnabled(
+      FeatureFlagKey.IS_DATASOURCE_MIGRATED,
+      workspace.id,
+    );
 
-    if (!dataSourcesMetadata || dataSourcesMetadata.length === 0) {
+    const hasSchema = isDataSourceMigrated
+      ? isNonEmptyString(workspace.databaseSchema)
+      : (
+          await this.dataSourceService.getDataSourcesMetadataFromWorkspaceId(
+            workspace.id,
+          )
+        ).length > 0;
+
+    if (!hasSchema) {
       return new GraphQLSchema({});
     }