[test] Run tests periodically with react@next

.circleci/config.yml

@@ -1,6 +1,14 @@
 version: 2.1
 
 defaults: &defaults
+  parameters:
+    react-dist-tag:
+      description: The dist-tag of react to be used
+      type: string
+      default: stable
+  environment:
+    # expose it globally otherwise we have to thread it from each job to the install command
+    REACT_DIST_TAG: << parameters.react-dist-tag >>
   working_directory: /tmp/material-ui
   docker:
     - image: circleci/node:8.15
@@ -16,6 +24,12 @@ defaults: &defaults
 commands:
   install_js:
     steps:
+      - run:
+          name: Resolve react version
+          command: |
+            node scripts/use-react-dist-tag
+            # log a patch for maintainers who want to check out this change
+            git diff HEAD
       - restore_cache:
           keys:
             - v2-yarn-sha-{{ checksum "yarn.lock" }}
@@ -157,7 +171,7 @@ workflows:
       - checkout:
           filters:
             branches:
-              ignore: 
+              ignore:
                 - l10n
                 - /dependabot\//
       - test_unit:
@@ -178,3 +192,21 @@ workflows:
             - test_static
             - test_types
             - test_browser
+  react-next:
+    triggers:
+      - schedule:
+          cron: '0 0 * * *'
+          filters:
+            branches:
+              only:
+                - master
+    jobs:
+      - test_unit:
+          react-dist-tag: next
+      - test_browser:
+          react-dist-tag: next
+      - test_regressions:
+          requires:
+            - test_unit
+            - test_browser
+          react-dist-tag: next

scripts/use-react-dist-tag.js

@@ -0,0 +1,55 @@
+/* eslint-disable no-console */
+/**
+ * Given an environment variable called `REACT_DIST_TAG` fetch the corresponding
+ * version and make sure this version is used throughout the repository.
+ *
+ * If you work on this file:
+ * WARNING: This script can only use built-in modules since it has to run before
+ * `yarn install`
+ */
+const childProcess = require('child_process');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const { promisify } = require('util');
+
+const exec = promisify(childProcess.exec);
+
+// packages published from the react monorepo using the same version
+const reactPackageNames = ['react', 'react-dom', 'react-is', 'react-test-renderer', 'scheduler'];
+
+async function main(distTag) {
+  if (typeof distTag !== 'string') {
+    throw new TypeError(`expected distTag: string but got '${distTag}'`);
+  }
+
+  if (distTag === 'stable') {
+    console.log('nothing to do with stable');
+    return;
+  }
+
+  const { stdout: versions } = await exec(`npm dist-tag ls react ${distTag}`);
+  const tagMapping = versions.split('\n').find(mapping => {
+    return mapping.startsWith(`${distTag}: `);
+  });
+  if (tagMapping === undefined) {
+    throw new Error(`Could not find '${distTag}' in "${versions}"`);
+  }
+
+  const version = tagMapping.replace(`${distTag}: `, '');
+
+  const packageJsonPath = path.resolve(__dirname, '../package.json');
+  const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, { encoding: 'utf8' }));
+
+  reactPackageNames.forEach(reactPackageName => {
+    packageJson.resolutions[reactPackageName] = version;
+  });
+
+  // CircleCI seemingly times out if it has a newline diff at the end
+  fs.writeFileSync(packageJsonPath, `${JSON.stringify(packageJson, null, 2)}${os.EOL}`);
+}
+
+main(process.env.REACT_DIST_TAG).catch(error => {
+  console.error(error);
+  process.exit(1);
+});