feat: move validation related to duplicated plugins configuration (ne…

…tlify#2566)

packages/config/src/merge.js

@@ -1,6 +1,5 @@
 'use strict'
 
-const { throwError } = require('./error')
 const { groupBy } = require('./utils/group')
 const { mergeConfigs } = require('./utils/merge')
 
@@ -37,12 +36,6 @@ const mergePluginConfigs = function (plugins) {
 
 // TODO: use deep merging instead
 const mergePluginsPair = function (pluginA, pluginB) {
-  // This most likely indicates that the user forgot that they already added or
-  // configured a plugin.
-  if (pluginA.origin === 'config' && pluginB.origin === 'config') {
-    throwError(`Plugin "${pluginA.package}" must not be specified twice in netlify.toml`)
-  }
-
   return { ...pluginA, ...pluginB }
 }
 

packages/config/src/merge_normalize.js

@@ -3,6 +3,7 @@
 const { normalizeConfigCase } = require('./case')
 const { normalizeConfig } = require('./normalize')
 const { addOrigins } = require('./origin')
+const { validateIdenticalPlugins } = require('./validate/identical.js')
 const {
   validatePreCaseNormalize,
   validatePreMergeConfig,
@@ -19,6 +20,7 @@ const normalizeBeforeConfigMerge = function (config, origin) {
   const configA = normalizeConfigCase(config)
   validatePreMergeConfig(configA)
   const configB = addOrigins(configA, origin)
+  validateIdenticalPlugins(configB)
   return configB
 }
 

packages/config/src/validate/identical.js

@@ -0,0 +1,24 @@
+'use strict'
+
+const { throwError } = require('../error')
+
+// Validate that plugin are configured only once per origin
+// (`netlify.toml` or UI).
+// Exception: context-specific configuration since we allow context-specific
+// overrides. This does not validate them since contexts have not been merged
+// yet.
+const validateIdenticalPlugins = function ({ plugins = [] }) {
+  plugins.filter(hasIdenticalPlugin).forEach(throwIndenticalPlugin)
+}
+
+const hasIdenticalPlugin = function ({ package: packageName, origin }, index, plugins) {
+  return plugins.slice(index + 1).some((pluginA) => packageName === pluginA.package && origin === pluginA.origin)
+}
+
+const throwIndenticalPlugin = function ({ package: packageName, origin }) {
+  throwError(`Plugin "${packageName}" must not be specified twice in ${ORIGINS[origin]}`)
+}
+
+const ORIGINS = { config: 'netlify.toml', ui: 'the app' }
+
+module.exports = { validateIdenticalPlugins }

packages/config/tests/validate/snapshots/tests.js.md

@@ -633,6 +633,13 @@ Generated by [AVA](https://ava.li).
     `When resolving config file packages/config/tests/validate/fixtures/plugins_duplicate/netlify.toml:␊
     Plugin "./plugin.js" must not be specified twice in netlify.toml`
 
+## plugins: do not allow duplicates in the UI
+
+> Snapshot 1
+
+    `When resolving config:␊
+    Plugin "test" must not be specified twice in the app`
+
 ## plugins: not array
 
 > Snapshot 1

packages/config/tests/validate/tests.js

@@ -16,6 +16,11 @@ test('plugins: do not allow duplicates', async (t) => {
   await runFixture(t, 'plugins_duplicate')
 })
 
+test('plugins: do not allow duplicates in the UI', async (t) => {
+  const defaultConfig = JSON.stringify({ plugins: [{ package: 'test' }, { package: 'test' }] })
+  await runFixture(t, 'empty', { flags: { defaultConfig } })
+})
+
 test('plugins.any: unknown property', async (t) => {
   await runFixture(t, 'plugins_unknown')
 })