Fix batched queries context cloning

lib/routes.js

@@ -358,7 +358,12 @@ module.exports = async function (app, opts) {
 
       return Promise.all(request.body.map(async (r, operationId) => {
         // Create individual reqs for multiple operations, otherwise reference the original req
-        const operationReq = operationsCount > 1 ? Object.create(request) : request
+        const operationReq = operationsCount > 1
+          ? {
+              ...request,
+              [kRequestContext]: Object.create(request[kRequestContext])
+            }
+          : request
 
         Object.assign(operationReq[kRequestContext], { operationId })
 

test/batched.js

@@ -388,3 +388,74 @@ test('POST batched query has an individual context for each operation', async (t
   sinon.assert.calledWith(contextSpy, 0, 2, sinon.match(/TestQuery/))
   sinon.assert.calledWith(contextSpy, 1, 2, sinon.match(/DoubleQuery/))
 })
+
+test('POST batched query respects custom class-based context', async (t) => {
+  const app = Fastify()
+
+  const schema = `
+    type Query {
+      test: String
+    }
+  `
+
+  class CustomContext {
+    constructor () {
+      this.test = 'custom'
+    }
+
+    method () {
+      return this.test
+    }
+  }
+
+  const resolvers = {
+    test: async (args, ctx) => {
+      t.type(ctx, 'object')
+      t.type(ctx.reply, 'object')
+      t.type(ctx.app, 'object')
+      t.type(ctx.method, 'function')
+      t.equal(ctx.test, 'custom')
+      t.equal(ctx.method(), 'custom')
+      t.equal(ctx.constructor, CustomContext)
+      return ctx.method()
+    }
+  }
+
+  app.register(GQL, {
+    schema,
+    resolvers,
+    context: (request, reply) => {
+      t.type(request, 'object')
+      t.type(reply, 'object')
+      return new CustomContext()
+    },
+    allowBatchedQueries: true
+  })
+
+  const post = await app.inject({
+    method: 'POST',
+    url: '/graphql',
+    body: [
+      {
+        operationName: 'TestQuery',
+        query: 'query TestQuery { test }'
+      },
+      {
+        operationName: 'DoubleQuery',
+        query: 'query DoubleQuery { test }'
+      }
+    ]
+  })
+
+  t.same(JSON.parse(post.body), [
+    {
+      data: {
+        test: 'custom'
+      }
+    }, {
+      data: {
+        test: 'custom'
+      }
+    }
+  ])
+})

test/hooks-with-batching.js

@@ -0,0 +1,78 @@
+'use strict'
+
+const { test } = require('tap')
+const Fastify = require('fastify')
+const sinon = require('sinon')
+const GQL = require('..')
+
+test('batched query has an individual context for each operation through all the lifecycle hooks', async (t) => {
+  const app = Fastify()
+
+  const preParsingSpy = sinon.spy()
+  const preValidationSpy = sinon.spy()
+  const preExecutionSpy = sinon.spy()
+  const onResolutionSpy = sinon.spy()
+
+  const schema = `
+      type Query {
+        test: String
+      }
+    `
+
+  const resolvers = {
+    test: () => 'test'
+  }
+
+  await app.register(GQL, {
+    schema,
+    resolvers,
+    allowBatchedQueries: true
+  })
+
+  app.graphql.addHook('preParsing', (_, __, ctx) => {
+    preParsingSpy(ctx.operationId, ctx.operationsCount, ctx.__currentQuery)
+  })
+
+  app.graphql.addHook('preValidation', (_, __, ctx) => {
+    preValidationSpy(ctx.operationId, ctx.operationsCount, ctx.__currentQuery)
+  })
+
+  app.graphql.addHook('preExecution', (_, __, ctx) => {
+    preExecutionSpy(ctx.operationId, ctx.operationsCount, ctx.__currentQuery)
+  })
+
+  app.graphql.addHook('onResolution', (_, ctx) => {
+    onResolutionSpy(ctx.operationId, ctx.operationsCount, ctx.__currentQuery)
+  })
+
+  await app.inject({
+    method: 'POST',
+    url: '/graphql',
+    body: [
+      {
+        operationName: 'TestQuery',
+        query: 'query TestQuery { test }'
+      },
+      {
+        operationName: 'DoubleQuery',
+        query: 'query DoubleQuery { test }'
+      }
+    ]
+  })
+
+  sinon.assert.calledTwice(preParsingSpy)
+  sinon.assert.calledWith(preParsingSpy, 0, 2, sinon.match(/TestQuery/))
+  sinon.assert.calledWith(preParsingSpy, 1, 2, sinon.match(/DoubleQuery/))
+
+  sinon.assert.calledTwice(preValidationSpy)
+  sinon.assert.calledWith(preValidationSpy, 0, 2, sinon.match(/TestQuery/))
+  sinon.assert.calledWith(preValidationSpy, 1, 2, sinon.match(/DoubleQuery/))
+
+  sinon.assert.calledTwice(preExecutionSpy)
+  sinon.assert.calledWith(preExecutionSpy, 0, 2, sinon.match(/TestQuery/))
+  sinon.assert.calledWith(preExecutionSpy, 1, 2, sinon.match(/DoubleQuery/))
+
+  sinon.assert.calledTwice(onResolutionSpy)
+  sinon.assert.calledWith(onResolutionSpy, 0, 2, sinon.match(/TestQuery/))
+  sinon.assert.calledWith(onResolutionSpy, 1, 2, sinon.match(/DoubleQuery/))
+})