From 2a5a330fa69876d67ea3f721f20f2161fa87cc25 Mon Sep 17 00:00:00 2001
From: Kyle Mathews <mathews.kyle@gmail.com>
Date: Mon, 29 Jan 2018 16:51:17 -0800
Subject: [PATCH] Improve errors for invalid data passed to createPage fixes
 #3771

---
 .../__tests__/__snapshots__/pages.js.snap     |  6 +++
 packages/gatsby/src/redux/__tests__/pages.js  | 31 +++++++++++++++
 packages/gatsby/src/redux/actions.js          | 39 +++++++++++++++++++
 3 files changed, 76 insertions(+)

diff --git a/packages/gatsby/src/redux/__tests__/__snapshots__/pages.js.snap b/packages/gatsby/src/redux/__tests__/__snapshots__/pages.js.snap
index 903d664a64343..dc49f11a2a274 100644
--- a/packages/gatsby/src/redux/__tests__/__snapshots__/pages.js.snap
+++ b/packages/gatsby/src/redux/__tests__/__snapshots__/pages.js.snap
@@ -1,5 +1,11 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`Add pages Fails if component path is missing 1`] = `"The plugin \\"test\\" must set the absolute path to the page component when create creating a page"`;
+
+exports[`Add pages Fails if path is missing 1`] = `"The plugin \\"test\\" must set the page path when creating a page"`;
+
+exports[`Add pages Fails if the component path isn't absolute 1`] = `"The plugin \\"test\\" must set the absolute path to the page component when create creating a page"`;
+
 exports[`Add pages allows you to add multiple pages 1`] = `
 Array [
   Object {
diff --git a/packages/gatsby/src/redux/__tests__/pages.js b/packages/gatsby/src/redux/__tests__/pages.js
index 404524586994c..34cff81f9aef8 100644
--- a/packages/gatsby/src/redux/__tests__/pages.js
+++ b/packages/gatsby/src/redux/__tests__/pages.js
@@ -21,6 +21,37 @@ describe(`Add pages`, () => {
     expect(state).toMatchSnapshot()
   })
 
+  it(`Fails if path is missing`, () => {
+    const action = actions.createPage(
+      {
+        component: `/whatever/index.js`,
+      },
+      { id: `test`, name: `test` }
+    )
+    expect(action).toMatchSnapshot()
+  })
+
+  it(`Fails if component path is missing`, () => {
+    const action = actions.createPage(
+      {
+        path: `/whatever/`,
+      },
+      { id: `test`, name: `test` }
+    )
+    expect(action).toMatchSnapshot()
+  })
+
+  it(`Fails if the component path isn't absolute`, () => {
+    const action = actions.createPage(
+      {
+        path: `/whatever/`,
+        component: `cheese.js`,
+      },
+      { id: `test`, name: `test` }
+    )
+    expect(action).toMatchSnapshot()
+  })
+
   it(`adds an initial forward slash if the user doesn't`, () => {
     const action = actions.createPage(
       {
diff --git a/packages/gatsby/src/redux/actions.js b/packages/gatsby/src/redux/actions.js
index 073cb18032b84..3e4a451ef32b6 100644
--- a/packages/gatsby/src/redux/actions.js
+++ b/packages/gatsby/src/redux/actions.js
@@ -104,6 +104,45 @@ const pascalCase = _.flow(_.camelCase, _.upperFirst)
  * })
  */
 actions.createPage = (page: PageInput, plugin?: Plugin, traceId?: string) => {
+  let noPageOrComponent = false
+  let name = `The plugin "${plugin.name}"`
+  if (plugin.name === `default-site-plugin`) {
+    name = `Your site's "gatsby-node.js"`
+  }
+  if (!page.path) {
+    const message = `${name} must set the page path when creating a page`
+    // Don't log out when testing
+    if (!process.env.NODE_ENV === `test`) {
+      console.log(chalk.bold.red(message))
+      console.log(``)
+      console.log(page)
+    } else {
+      return message
+    }
+    noPageOrComponent = true
+  }
+
+  if (!page.component || !path.isAbsolute(page.component)) {
+    const message = `${name} must set the absolute path to the page component when create creating a page`
+    // Don't log out when testing
+    if (!process.env.NODE_ENV === `test`) {
+      console.log(chalk.bold.red(message))
+      console.log(``)
+      console.log(page)
+    } else {
+      return message
+    }
+    noPageOrComponent = true
+  }
+
+  if (noPageOrComponent) {
+    console.log(``)
+    console.log(
+      `See the documentation for createPage https://www.gatsbyjs.org/docs/bound-action-creators/#createPage`
+    )
+    process.exit(1)
+  }
+
   let jsonName = `${_.kebabCase(page.path)}.json`
   let internalComponentName = `Component${pascalCase(page.path)}`