feat: add hint which plugin is requesting specific decorator (fastify#2778)

Author: metcoder95

Diff for: lib/pluginUtils.js

@@ -67,21 +67,22 @@ function checkDecorators (fn) {
   const meta = getMeta(fn)
   if (!meta) return
 
-  const decorators = meta.decorators
+  const { decorators, name } = meta
   if (!decorators) return
 
-  if (decorators.fastify) _checkDecorators.call(this, 'Fastify', decorators.fastify)
-  if (decorators.reply) _checkDecorators.call(this[kReply], 'Reply', decorators.reply)
-  if (decorators.request) _checkDecorators.call(this[kRequest], 'Request', decorators.request)
+  if (decorators.fastify) _checkDecorators.call(this, 'Fastify', decorators.fastify, name)
+  if (decorators.reply) _checkDecorators.call(this[kReply], 'Reply', decorators.reply, name)
+  if (decorators.request) _checkDecorators.call(this[kRequest], 'Request', decorators.request, name)
 }
 
-function _checkDecorators (instance, decorators) {
+function _checkDecorators (instance, decorators, name) {
   assert(Array.isArray(decorators), 'The decorators should be an array of strings')
 
   decorators.forEach(decorator => {
+    const withPluginName = typeof name === 'string' ? ` required by '${name}'` : ''
     assert(
       instance === 'Fastify' ? decorator in this : decorator in this.prototype,
-      `The decorator '${decorator}' is not present in ${instance}`
+      `The decorator '${decorator}'${withPluginName} is not present in ${instance}`
     )
   })
 }

Diff for: test/plugin.test.js

@@ -725,6 +725,61 @@ test('plugin metadata - decorators', t => {
   }
 })
 
+test('plugin metadata - decorators - should throw', t => {
+  t.plan(1)
+  const fastify = Fastify()
+
+  fastify.decorate('plugin1', true)
+  fastify.decorateReply('plugin1', true)
+
+  plugin[Symbol.for('skip-override')] = true
+  plugin[Symbol.for('plugin-meta')] = {
+    decorators: {
+      fastify: ['plugin1'],
+      reply: ['plugin1'],
+      request: ['plugin1']
+    }
+  }
+
+  fastify.register(plugin)
+  fastify.ready((err) => {
+    t.equals(err.message, "The decorator 'plugin1' is not present in Request")
+  })
+
+  function plugin (instance, opts, next) {
+    instance.decorate('plugin', true)
+    next()
+  }
+})
+
+test('plugin metadata - decorators - should throw with plugin name', t => {
+  t.plan(1)
+  const fastify = Fastify()
+
+  fastify.decorate('plugin1', true)
+  fastify.decorateReply('plugin1', true)
+
+  plugin[Symbol.for('skip-override')] = true
+  plugin[Symbol.for('plugin-meta')] = {
+    name: 'the-plugin',
+    decorators: {
+      fastify: ['plugin1'],
+      reply: ['plugin1'],
+      request: ['plugin1']
+    }
+  }
+
+  fastify.register(plugin)
+  fastify.ready((err) => {
+    t.equals(err.message, "The decorator 'plugin1' required by 'the-plugin' is not present in Request")
+  })
+
+  function plugin (instance, opts, next) {
+    instance.decorate('plugin', true)
+    next()
+  }
+})
+
 test('plugin metadata - dependencies', t => {
   t.plan(1)
   const fastify = Fastify()