Make Danger Phabricator-friendly. (#32642)

Summary:
Pull Request resolved: #32642

This Diff adapts the Dangerfile to be a bit more friendly
for PRs that are exported from Phabricator. Specifically,
I'm disabling the check for Test Plan as those are not exported
externally. The check for Summary and Changelog are instead adapted
to work with the format exported for Phabricator.

Changelog:
[Internal] [Changed] - Make Danger Phabricator-friendly

Reviewed By: yungsters

Differential Revision: D32594622

fbshipit-source-id: e31f29defdd926a267cecc9efa6d63de2e580f43

Author: cortinico

bots/dangerfile.js

@@ -12,13 +12,18 @@
 const {danger, fail, message, warn} = require('danger');
 const includes = require('lodash.includes');
 
+const isFromPhabricator =
+  danger.github.pr.body &&
+  danger.github.pr.body.toLowerCase().includes('differential revision:');
+
 // Provides advice if a summary section is missing, or body is too short
 const includesSummary =
   danger.github.pr.body &&
   danger.github.pr.body.toLowerCase().includes('## summary');
 if (!danger.github.pr.body || danger.github.pr.body.length < 50) {
   fail(':grey_question: This pull request needs a description.');
-} else if (!includesSummary) {
+} else if (!includesSummary && !isFromPhabricator) {
+  // PRs from Phabricator always includes the Summary by default.
   const title = ':clipboard: Missing Summary';
   const idea =
     'Can you add a Summary? ' +
@@ -41,7 +46,8 @@ if (packageChanged) {
 const includesTestPlan =
   danger.github.pr.body &&
   danger.github.pr.body.toLowerCase().includes('## test plan');
-if (!includesTestPlan) {
+if (!includesTestPlan && !isFromPhabricator) {
+  // PRs from Phabricator never exports the Test Plan so let's disable this check.
   const title = ':clipboard: Missing Test Plan';
   const idea =
     'Can you add a Test Plan? ' +
@@ -57,7 +63,9 @@ const internalChangelogRegex = /\[\s?(INTERNAL)\s?\].*/gi;
 const includesChangelog =
   danger.github.pr.body &&
   (danger.github.pr.body.toLowerCase().includes('## changelog') ||
-    danger.github.pr.body.toLowerCase().includes('release notes'));
+    danger.github.pr.body.toLowerCase().includes('release notes') ||
+    // PR exports from Phabricator have a `Changelog:` entry for the changelog.
+    danger.github.pr.body.toLowerCase().includes('changelog:'));
 const correctlyFormattedChangelog = changelogRegex.test(danger.github.pr.body);
 const containsInternalChangelog = internalChangelogRegex.test(
   danger.github.pr.body,