Add warning when node-creating plugins create no nodes

The warning serves two purposes: a) to notify those that are using the plugin that it hasn't created any nodes and can likely be removed, and b) to reduce the confusion caused by a GraphQL query for a specific node erroring as no nodes have been created yet. See gatsbyjs#2212 for more. As part of this work, two key changes have been made to the redux store: a) Each plugin now has a `nodeAPIs` key whose value retains an array of strings denoting the names of which Gatsby APIs the plugin implements. b) At the root of the store, a new key exists named `apiToPlugins` has been created which stores a simple key -> val map from the name of a Gatsby API, to an array containing the string names of all plugins which implement that API. a) is helpful when needing to know what APIs a given plugin implements and b) is helpful when code requires a quick look up of which plugins implement a specific API - we pay the cost once at creation time rather than iterating through the plugin objects whenever we need to know.
djm · Oct 22, 2017 · fba53c4 · fba53c4
1 parent ad99189
commit fba53c4
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Showing 5 changed files with 106 additions and 3 deletions.
diff --git a/packages/gatsby/src/bootstrap/__tests__/__snapshots__/load-plugins.js.snap b/packages/gatsby/src/bootstrap/__tests__/__snapshots__/load-plugins.js.snap
@@ -5,6 +5,9 @@ Array [
   Object {
     "id": "Plugin component-page-creator",
     "name": "component-page-creator",
+    "nodeAPIs": Array [
+      "createPagesStatefully",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -14,6 +17,9 @@ Array [
   Object {
     "id": "Plugin component-layout-creator",
     "name": "component-layout-creator",
+    "nodeAPIs": Array [
+      "createLayouts",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -23,6 +29,10 @@ Array [
   Object {
     "id": "Plugin internal-data-bridge",
     "name": "internal-data-bridge",
+    "nodeAPIs": Array [
+      "sourceNodes",
+      "onCreatePage",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -32,6 +42,9 @@ Array [
   Object {
     "id": "Plugin dev-404-page",
     "name": "dev-404-page",
+    "nodeAPIs": Array [
+      "createPages",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -41,6 +54,9 @@ Array [
   Object {
     "id": "Plugin prod-404",
     "name": "prod-404",
+    "nodeAPIs": Array [
+      "onCreatePage",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -50,6 +66,10 @@ Array [
   Object {
     "id": "Plugin query-runner",
     "name": "query-runner",
+    "nodeAPIs": Array [
+      "onCreatePage",
+      "onCreateLayout",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -58,6 +78,7 @@ Array [
   },
   Object {
     "name": "TEST",
+    "nodeAPIs": Array [],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -66,6 +87,7 @@ Array [
   Object {
     "id": "Plugin default-site-plugin",
     "name": "default-site-plugin",
+    "nodeAPIs": Array [],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -80,6 +102,9 @@ Array [
   Object {
     "id": "Plugin component-page-creator",
     "name": "component-page-creator",
+    "nodeAPIs": Array [
+      "createPagesStatefully",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -89,6 +114,9 @@ Array [
   Object {
     "id": "Plugin component-layout-creator",
     "name": "component-layout-creator",
+    "nodeAPIs": Array [
+      "createLayouts",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -98,6 +126,10 @@ Array [
   Object {
     "id": "Plugin internal-data-bridge",
     "name": "internal-data-bridge",
+    "nodeAPIs": Array [
+      "sourceNodes",
+      "onCreatePage",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -107,6 +139,9 @@ Array [
   Object {
     "id": "Plugin dev-404-page",
     "name": "dev-404-page",
+    "nodeAPIs": Array [
+      "createPages",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -116,6 +151,9 @@ Array [
   Object {
     "id": "Plugin prod-404",
     "name": "prod-404",
+    "nodeAPIs": Array [
+      "onCreatePage",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -125,6 +163,10 @@ Array [
   Object {
     "id": "Plugin query-runner",
     "name": "query-runner",
+    "nodeAPIs": Array [
+      "onCreatePage",
+      "onCreateLayout",
+    ],
     "pluginOptions": Object {
       "plugins": Array [],
     },
@@ -134,6 +176,7 @@ Array [
   Object {
     "id": "Plugin default-site-plugin",
     "name": "default-site-plugin",
+    "nodeAPIs": Array [],
     "pluginOptions": Object {
       "plugins": Array [],
     },

diff --git a/packages/gatsby/src/bootstrap/load-plugins.js b/packages/gatsby/src/bootstrap/load-plugins.js
@@ -192,12 +192,19 @@ module.exports = async (config = {}) => {
     extractPlugins(plugin)
   })
 
-  // Validate plugins before saving. Plugins can only export known APIs. Collect
-  // any bad exports (either typos or outdated) and output an error and quit.
+  // Validate plugins before saving. Plugins can only export known APIs. The known
+  // APIs that a plugin supports are saved along with the plugin in the store for
+  // easier filtering later. If there are bad exports (either typos, outdated, or
+  // plain incorrect), then we output a readable error & quit.
   const apis = _.keys(nodeAPIs)
+  const apiToPlugins = apis.reduce((acc, value) => {
+    acc[value] = []
+    return acc
+  }, {})
   let badExports = []
   flattenedPlugins.forEach(plugin => {
     let gatsbyNode
+    plugin.nodeAPIs = []
     try {
       gatsbyNode = require(`${plugin.resolve}/gatsby-node`)
     } catch (err) {
@@ -209,8 +216,15 @@ module.exports = async (config = {}) => {
     }
 
     if (gatsbyNode) {
+      const gatsbyNodeKeys = _.keys(gatsbyNode)
+      // Discover which nodeAPIs this plugin implements and store
+      // an array against the plugin node itself *and* in a node
+      // API to plugins map for faster lookups later.
+      plugin.nodeAPIs = _.intersection(gatsbyNodeKeys, apis)
+      plugin.nodeAPIs.map(nodeAPI => apiToPlugins[nodeAPI].push(plugin.name))
+      // Discover any exports from plugins which are not "known"
       badExports = badExports.concat(
-        _.without(_.keys(gatsbyNode), ...apis).map(e => {
+        _.difference(gatsbyNodeKeys, apis).map(e => {
           return {
             exportName: e,
             pluginName: plugin.name,
@@ -264,5 +278,10 @@ module.exports = async (config = {}) => {
     payload: flattenedPlugins,
   })
 
+  store.dispatch({
+    type: `SET_SITE_API_TO_PLUGINS`,
+    payload: apiToPlugins,
+  })
+
   return flattenedPlugins
 }
diff --git a/packages/gatsby/src/redux/reducers/api-to-plugins.js b/packages/gatsby/src/redux/reducers/api-to-plugins.js
@@ -0,0 +1,8 @@
+module.exports = (state = [], action) => {
+  switch (action.type) {
+    case `SET_SITE_API_TO_PLUGINS`:
+      return { ...action.payload }
+    default:
+      return state
+  }
+}
diff --git a/packages/gatsby/src/redux/reducers/index.js b/packages/gatsby/src/redux/reducers/index.js
@@ -5,6 +5,7 @@ module.exports = {
   lastAction: require(`./last-action`),
   plugins: require(`./plugins`),
   flattenedPlugins: require(`./flattened-plugins`),
+  apiToPlugins: require(`./api-to-plugins`),
   config: require(`./config`),
   pages: require(`./pages`),
   layouts: require(`./layouts`),

diff --git a/packages/gatsby/src/utils/source-nodes.js b/packages/gatsby/src/utils/source-nodes.js
@@ -1,10 +1,34 @@
 const _ = require(`lodash`)
+const report = require(`gatsby-cli/lib/reporter`)
 
 const apiRunner = require(`./api-runner-node`)
 const { store, getNode } = require(`../redux`)
 const { boundActionCreators } = require(`../redux/actions`)
 const { deleteNodes } = boundActionCreators
 
+/**
+ * Finds the name of all plugins which implement Gatsby APIs that
+ * may create nodes, but which have not actually created any nodes.
+ */
+function discoverPluginsWithoutNodes(storeState) {
+  // Discover which plugins implement APIs which may create nodes
+  const nodeCreationPlugins = _.without(
+    _.union(
+      storeState.apiToPlugins.sourceNodes,
+      storeState.apiToPlugins.onCreateNode
+    ),
+    `default-site-plugin`
+  )
+  // Find out which plugins own already created nodes
+  const nodeOwners = _.uniq(
+    _.values(storeState.nodes).reduce((acc, node) => {
+      acc.push(node.internal.owner)
+      return acc
+    }, [])
+  )
+  return _.difference(nodeCreationPlugins, nodeOwners)
+}
+
 module.exports = async () => {
   await apiRunner(`sourceNodes`, {
     traceId: `initial-sourceNodes`,
@@ -13,6 +37,14 @@ module.exports = async () => {
 
   const state = store.getState()
 
+  // Warn about plugins that should have created nodes but didn't.
+  const pluginsWithNoNodes = discoverPluginsWithoutNodes(state)
+  pluginsWithNoNodes.map(name =>
+    report.warn(
+      `The ${name} plugin has generated no Gatsby nodes. Do you need it?`
+    )
+  )
+
   // Garbage collect stale data nodes
   const touchedNodes = Object.keys(state.nodesTouched)
   const staleNodes = _.values(state.nodes).filter(node => {