feat: restrict deletion for context vars that are in use

api/src/chat/controllers/context-var.controller.spec.ts

@@ -137,7 +137,7 @@ describe('ContextVarController', () => {
         contextVarController.deleteOne(contextVarToDelete.id),
       ).rejects.toThrow(
         new NotFoundException(
-          `ContextVar with ID ${contextVarToDelete.id} not found`,
+          `Context var with ID ${contextVarToDelete.id} not found.`,
         ),
       );
     });

api/src/chat/repositories/context-var.repository.ts

@@ -6,21 +6,70 @@
  * 2. All derivative works must include clear attribution to the original creator and software, Hexastack and Hexabot, in a prominent location (e.g., in the software's "About" section, documentation, and README file).
  */
 
-import { Injectable } from '@nestjs/common';
+import {
+  ForbiddenException,
+  Injectable,
+  NotFoundException,
+  Optional,
+} from '@nestjs/common';
 import { EventEmitter2 } from '@nestjs/event-emitter';
 import { InjectModel } from '@nestjs/mongoose';
-import { Model } from 'mongoose';
+import { Document, Model, Query, TFilterQuery } from 'mongoose';
 
-import { BaseRepository } from '@/utils/generics/base-repository';
+import { BaseRepository, DeleteResult } from '@/utils/generics/base-repository';
 
 import { ContextVar } from '../schemas/context-var.schema';
+import { BlockService } from '../services/block.service';
 
 @Injectable()
 export class ContextVarRepository extends BaseRepository<ContextVar> {
+  private readonly blockService: BlockService;
+
   constructor(
     readonly eventEmitter: EventEmitter2,
     @InjectModel(ContextVar.name) readonly model: Model<ContextVar>,
+    @Optional() blockService?: BlockService,
   ) {
     super(eventEmitter, model, ContextVar);
+    this.blockService = blockService;
+  }
+
+  /**
+   * Pre-processing logic before deleting a context var.
+   * It avoids deleting a context var if its unique name is used in blocks within the capture_vars array.
+   * If the context var is found in blocks, the block IDs are returned in the exception message.
+   *
+   * @param query - The delete query.
+   * @param criteria - The filter criteria for finding context vars to delete.
+   */
+  async preDelete(
+    _query: Query<
+      DeleteResult,
+      Document<ContextVar, any, any>,
+      unknown,
+      ContextVar,
+      'deleteOne' | 'deleteMany'
+    >,
+    criteria: TFilterQuery<ContextVar>,
+  ) {
+    const ids = Array.isArray(criteria._id) ? criteria._id : [criteria._id];
+
+    for (const id of ids) {
+      const contextVar = await this.findOne({ _id: id });
+      if (!contextVar) {
+        throw new NotFoundException(`Context var with ID ${id} not found.`);
+      }
+
+      const associatedBlocks = await this.blockService?.find({
+        capture_vars: { $elemMatch: { context_var: contextVar.name } },
+      });
+
+      if (associatedBlocks?.length > 0) {
+        const blockIds = associatedBlocks.map((block) => block.id).join(', ');
+        throw new ForbiddenException(
+          `Context var "${contextVar.name}" is associated with the following block(s): ${blockIds} and cannot be deleted.`,
+        );
+      }
+    }
   }
 }

api/src/chat/schemas/context-var.schema.ts

@@ -10,6 +10,7 @@ import { Prop, Schema, SchemaFactory, ModelDefinition } from '@nestjs/mongoose';
 import { THydratedDocument } from 'mongoose';
 
 import { BaseSchema } from '@/utils/generics/base-schema';
+import { LifecycleHookManager } from '@/utils/generics/lifecycle-hook-manager';
 
 @Schema({ timestamps: true })
 export class ContextVar extends BaseSchema {
@@ -40,10 +41,10 @@ export class ContextVar extends BaseSchema {
   permanent?: boolean;
 }
 
-export const ContextVarModel: ModelDefinition = {
+export const ContextVarModel: ModelDefinition = LifecycleHookManager.attach({
   name: ContextVar.name,
   schema: SchemaFactory.createForClass(ContextVar),
-};
+});
 
 export type ContextVarDocument = THydratedDocument<ContextVar>;
 

frontend/src/components/categories/index.tsx

@@ -138,8 +138,7 @@ export const Categories = () => {
           if (selectedCategories.length > 0) {
             deleteCategories(selectedCategories), setSelectedCategories([]);
             deleteDialogCtl.closeDialog();
-          }
-          if (deleteDialogCtl?.data) {
+          } else if (deleteDialogCtl?.data) {
             {
               deleteCategory(deleteDialogCtl.data);
               deleteDialogCtl.closeDialog();

frontend/src/components/context-vars/index.tsx

@@ -63,8 +63,8 @@ export const ContextVars = () => {
     },
   });
   const { mutateAsync: deleteContextVar } = useDelete(EntityType.CONTEXT_VAR, {
-    onError: () => {
-      toast.error(t("message.internal_server_error"));
+    onError: (error) => {
+      toast.error(error);
     },
     onSuccess() {
       deleteDialogCtl.closeDialog();
@@ -76,7 +76,7 @@ export const ContextVars = () => {
     EntityType.CONTEXT_VAR,
     {
       onError: (error) => {
-        toast.error(error.message || t("message.internal_server_error"));
+        toast.error(error);
       },
       onSuccess: () => {
         deleteDialogCtl.closeDialog();