From f2020ccff17df5f19617554f85c0f6179943962b Mon Sep 17 00:00:00 2001
From: Oliver Davies <opdavies@gmail.com>
Date: Mon, 23 Apr 2018 21:30:24 +0100
Subject: [PATCH] Add post

---
 source/_layouts/post.html.twig                |  1 +
 ...04-23-back-to-the-future-git-diff-apply.md | 56 +++++++++++++++++++
 source/blog.html                              |  1 +
 3 files changed, 58 insertions(+)
 create mode 100644 source/_posts/2018-04-23-back-to-the-future-git-diff-apply.md

diff --git a/source/_layouts/post.html.twig b/source/_layouts/post.html.twig
index 7dfd27b1..eb5e181d 100644
--- a/source/_layouts/post.html.twig
+++ b/source/_layouts/post.html.twig
@@ -34,6 +34,7 @@
             </div>
         {% endif %}
 
+        {{ page.summary|markdown }}
         {% block excerpt %}{% endblock %}
         {% block content %}{% endblock %}
     </div>
diff --git a/source/_posts/2018-04-23-back-to-the-future-git-diff-apply.md b/source/_posts/2018-04-23-back-to-the-future-git-diff-apply.md
new file mode 100644
index 00000000..1a6fde0c
--- /dev/null
+++ b/source/_posts/2018-04-23-back-to-the-future-git-diff-apply.md
@@ -0,0 +1,56 @@
+---
+title: Back to the future with Git’s diff and apply commands
+summary: |
+    This is one of those “there’s probably already a better way to do this” situations, but it worked.
+
+    I was having some issues this past weekend where, despite everything working fine locally, a server was showing a “500 Internal Server” after I pushed some changes to a site. In order to bring the site back online, I needed to revert the site files back to the previous version, but as part of a new commit.
+tags:
+    - git
+draft: true
+slug: back-to-the-future-git-diff-apply
+---
+The `git reset` commands removed the interim commits which meant that I couldn’t push to the remote (force pushing, quite rightly, isn’t allowed for the production branch), and using `git revert` was resulting in merge conflicts in `composer.lock` that I’d rather have avoided if possible.
+
+This is what `git log --oneline -n 4` was outputting:
+
+```
+14e40bc Change webflo/drupal-core-require-dev version
+fc058bb Add services.yml
+60bcf33 Update composer.json and re-generate lock file
+722210c More styling
+```
+
+`722210c` is the commit SHA that I needed to go back to.
+
+## First Solution
+
+My first solution was to use `git diff` to create a single patch file of all of the changes from the current point back to the original commit. In this case, I’m using `head~3` (four commits before `head`) as the original reference, I could have alternatively used a commit ID, tag or branch name.
+
+```
+git diff head head~3 > temp.patch
+git apply -v temp.patch
+```
+
+With the files are back in the former state, I can remove the patch, add the files as a new commit and push them to the remote.
+
+```
+rm temp.patch
+
+git add .
+git commit -m 'Back to the future'
+git push
+```
+
+Although the files are back in their previous, working state, as this is a new commit with a new commit SHA reference, there is no issue with the remote rejecting the commit or needing to attempt to force push.
+
+## Second Solution
+
+The second solution is just a shorter, cleaner version of the first!
+
+Rather than creating a patch file and applying it, the output from `git diff` can be piped straight into `git apply`.
+
+```
+git diff head~3 head | git apply -v
+```
+
+This means that there’s only one command to run and no leftover patch file, and I can go ahead and add and commit the changes straight away.
diff --git a/source/blog.html b/source/blog.html
index 6579fbe5..f26a43d1 100644
--- a/source/blog.html
+++ b/source/blog.html
@@ -20,6 +20,7 @@ use: [posts]
                 {% include 'post/intro-image' with { page: post } %}
 
                 <div class="mb-4">
+                    {{ post.summary|markdown }}
                     {% if post.blocks.excerpt is defined %}
                         {{ post.blocks.excerpt|markdown }}
                     {% else %}