Optimised fixture replacement migration script (#9812)

no issue

- do only look for published old fixture posts
  - otherwise we detect draft old fixture post
  - and then we would replace them with published new fixture posts, which is not a very nice experience for the user
- ensure, if we have found all old fixture posts, replace all of them with the correct date
  - otherwise they are getting replaced and the date is "now"
- in general, this migration script is tricky and it tries to be smart, but there are so many cases we can run into
- to remember: the goal was to replace all old with new fixture posts (e.g. you just installed 1.25 and straight migrate to 2.0 - the old fixture posts should get replaced)
- added more protections to ensure we never delete custom posts using the same fixture post slugs

core/server/data/migrations/versions/2.0/6-replace-fixture-posts.js

@@ -1,34 +1,74 @@
 const Promise = require('bluebird');
 const _ = require('lodash');
+const moment = require('moment-timezone');
 const models = require('../../../../models');
 const fixtures = require('../../../../data/schema/fixtures');
 const common = require('../../../../lib/common');
 const message1 = 'Replacing fixture posts.';
 const message2 = 'Replaced fixture posts.';
 const message3 = 'Rollback: Fixture posts.';
 
-const oldFixtureSlugs = ['welcome', 'the-editor', 'using-tags', 'managing-users', 'private-sites', 'advanced-markdown', 'themes'];
+const oldFixtures = [
+    {
+        slug: 'welcome',
+        title: 'Welcome to Ghost'
+    },
+    {
+        slug: 'the-editor',
+        title: 'Using the Ghost editor'
+    },
+    {
+        slug: 'using-tags',
+        title: 'Organising your content with tags'
+    },
+    {
+        slug: 'managing-users',
+        title: 'Managing Ghost users'
+    },
+    {
+        slug: 'private-sites',
+        title: 'Making your site private'
+    },
+    {
+        slug: 'advanced-markdown',
+        title: 'Advanced Markdown tips'
+    },
+    {
+        slug: 'themes',
+        title: 'Setting up your own Ghost theme'
+    }
+];
+
 const newFixtureSlugs = _.map(_.find(fixtures.models, {name: 'Post'}).entries, 'slug');
 
 module.exports.config = {
     transaction: true
 };
 
+// This migration scripts tries to cover one case: you have a fresh installed v1 blog and you migrate to v2.
+// We try to replace the old fixture posts with the new fixture posts.
 module.exports.up = (options) => {
     let localOptions = _.merge({
         context: {internal: true},
-        columns: ['id'],
+        columns: ['id', 'updated_at', 'created_at', 'published_at', 'title', 'slug'],
         withRelated: ['authors', 'tags'],
         migrating: true
     }, options);
 
     common.logging.info(message1);
     let oldFixturePostsCount = 0;
 
-    return Promise.each(oldFixtureSlugs, (slug) => {
-        return models.Post.findOne({slug: slug, status: 'all'}, localOptions)
+    // Remember a reference date of the old fixture posts
+    let createdAt;
+    let updatedAt;
+    let publishedAt;
+
+    return Promise.each(_.map(oldFixtures, 'slug'), (slug) => {
+        // Look for published old fixture posts
+        return models.Post.findOne({slug: slug}, localOptions)
             .then((model) => {
-                // CASE: fixture post doesn't exist
+                // CASE 1: old fixture post doesn't exist
+                // CASE 2: old fixture post not published, ignore
                 if (!model) {
                     return;
                 }
@@ -40,23 +80,53 @@ module.exports.up = (options) => {
                     return;
                 }
 
-                // CASE: the old fixture post is NOT tagged with getting started
+                // CASE: could be your own post, the fixture posts only have 1 primary author by default
+                if (model.authors.length === 2) {
+                    return;
+                }
+
+                // CASE: the old fixture post is NOT tagged with getting started, could be your own post
                 if (!_.find(model.tags, {slug: 'getting-started'})) {
                     return;
                 }
 
+                // CASE: could be your own post, the fixture posts only have 1 primary tag by default
+                if (model.tags.length === 2) {
+                    return;
+                }
+
+                // CASE: title equals old fixture post, ensure it's not your own post
+                if (model.title !== _.find(oldFixtures, {slug: model.slug}).title) {
+                    return;
+                }
+
                 oldFixturePostsCount = oldFixturePostsCount + 1;
+
+                // remember date ref
+                createdAt = model.created_at;
+                updatedAt = model.updated_at;
+                publishedAt = model.published_at;
+
+                // destroy the old published fixture post
                 return models.Post.destroy(Object.assign({id: model.id}, localOptions));
             });
     }).then(() => {
-        // We only insert the new post fixtures if you had ALL old fixure posts in the database
+        // CASE: We only insert the new post fixtures if you had all old fixture posts in the database and they were published
+        // Otherwise we have no clue in which state your blog is in.
         if (oldFixturePostsCount !== 7) {
             return;
         }
 
-        const newPostFixtures = fixtures.utils.findModelFixtures('Post');
+        const newPostFixtures = _.cloneDeep(fixtures.utils.findModelFixtures('Post'));
         const newPostRelationFixtures = fixtures.utils.findRelationFixture('Post', 'Tag');
 
+        // Add all the new post fixtures with the old and correct reference date
+        _.forEach(newPostFixtures.entries, function (post, index) {
+            post.created_at = createdAt;
+            post.updated_at = updatedAt;
+            post.published_at = moment(publishedAt).add(index, 'seconds').toDate();
+        });
+
         return fixtures.utils.addFixturesForModel(newPostFixtures, _.omit(localOptions, ['withRelated', 'columns']))
             .then(() => {
                 return fixtures.utils.addFixturesForRelation(newPostRelationFixtures, _.omit(localOptions, ['withRelated', 'columns']));
@@ -69,7 +139,7 @@ module.exports.up = (options) => {
 module.exports.down = (options) => {
     let localOptions = _.merge({
         context: {internal: true},
-        columns: ['id'],
+        columns: ['id', 'title', 'slug'],
         withRelated: ['authors', 'tags'],
         migrating: true
     }, options);
@@ -79,7 +149,7 @@ module.exports.down = (options) => {
     return Promise.each(newFixtureSlugs, (slug) => {
         return models.Post.findOne({slug: slug, status: 'all'}, localOptions)
             .then((model) => {
-                // CASE: fixture post doesn't exist
+                // CASE: new fixture post doesn't exist
                 if (!model) {
                     return;
                 }
@@ -91,11 +161,26 @@ module.exports.down = (options) => {
                     return;
                 }
 
+                // CASE: could be your own post, the fixture posts only have 1 primary author by default
+                if (model.authors.length === 2) {
+                    return;
+                }
+
                 // CASE: the old fixture post is NOT tagged with getting started
                 if (!_.find(model.tags, {slug: 'getting-started'})) {
                     return;
                 }
 
+                // CASE: could be your own post, the fixture posts only have 1 primary tag by default
+                if (model.tags.length === 2) {
+                    return;
+                }
+
+                // CASE: ensure it's not your own post
+                if (model.title !== _.find(_.find(fixtures.models, {name: 'Post'}).entries, {slug: model.slug}).title) {
+                    return;
+                }
+
                 return models.Post.destroy(Object.assign({id: model.id}, localOptions));
             });
     });