shit-happens chapter :P

levels/sequence

@@ -1,4 +1,5 @@
 stash
 index
+shit-happens
 time-machine
 low-level

levels/shit-happens/bad-commit

@@ -0,0 +1,30 @@
+title = Undo a bad commit
+cards = reset commit-a
+
+[description]
+
+Oh no, we made a bad commit! How can we undo making the commit, and go back to a point where we can try again?
+
+The answer is using `git reset [commit]`, which does two things:
+
+- It resets the current branch ref to the commit you specify.
+- And it resets the index to that commit.
+
+It does not change your working directory in any way, which means that after that, you can try making the commit you want again.
+
+[setup]
+
+echo "1 2 3 4" > numbers
+git add .
+git commit -m "Initial commit"
+echo "1 2 3 4 5 6 7 8 9 11" > numbers
+git commit -am "More numberrrrrs"
+
+[win]
+
+# In the last main commit, the numbers file contains the numbers from 1 to 10.
+test "$(git show main:numbers)" = "1 2 3 4 5 6 7 8 9 10"
+# The commit message of that commit is "More numbers".
+git log -1 --oneline | grep "More numbers"
+# The commit with the typo is not part of the main branch anymore.
+git log --oneline | grep -v "rrrrr"

levels/shit-happens/pushed-something-broken

@@ -0,0 +1,54 @@
+title = I pushed something broken
+cards = revert push
+
+[description]
+
+We were talking about how to undo a commit, and fix it. This only helps when you haven't already pushed it to a remote. When that has happened, and you want to undo the effects of the commit completely, your best option is `git revert`
+
+[setup]
+
+echo "this is fine
+
+?
+
+?
+
+?" > text
+git add .
+git commit -m fine
+echo "this is fine
+
+this is also fine
+
+?
+
+?" > text
+git commit -am "also fine"
+echo "this is fine
+
+this is also fine
+
+this is very bad
+
+?" > text
+git commit -am "very bad"
+echo "this is fine
+
+this is also fine
+
+this is very bad
+
+this is fine again" > text
+git commit -am "fine again"
+
+git push team main
+git branch -u team/main main
+
+[setup team]
+
+[win team]
+
+# The team's main branch no longer contains the bad thing.
+! { git show main:text | grep -q "very bad"; }
+# And the history has not been modified.
+git show main^:text | grep -q "very bad"

levels/shit-happens/reflog

@@ -0,0 +1,26 @@
+title = Go back to where you were before
+cards = checkout reflog
+
+[description]
+
+Say you were looking at something in the past, and then switched back to the main branch.
+
+But then, you got reaaally distracted, and after your lunch break, you can't remember on which commit in the past you were before. How can you find out?
+
+There's a convenient command that shows you all the places your HEAD did point to in the past:
+
+    git reflog
+
+[setup]
+
+for i in {1..10}; do
+    git commit --allow-empty -m $i
+    git branch $i
+done
+git checkout 3
+git checkout main
+
+[win]
+
+# Find out where you've been before, and go back there!
+test "$(git rev-parse HEAD)" = "$(git rev-parse 3)"

levels/shit-happens/restore-a-file

@@ -0,0 +1,21 @@
+title = Restore a file from the past
+cards = checkout checkout-from commit
+
+[description]
+
+Here's a similar problem: you really liked the essay from the very first commit, and want to have it back! Well, checkout can also restore things from older commits, Here's how:
+
+    git checkout [commit] [file]
+
+[setup]
+
+echo "good version" > essay
+git add .
+git commit -m "Initial commit"
+echo "bad version" > essay
+git commit -am "\"Improve\" essay"
+
+[win]
+
+# Get the first version of your essay, and make a new commit with it.
+test "$(git show main:essay)" = "good version"

levels/shit-happens/restore-a-file-from-the-past

@@ -0,0 +1,22 @@
+title = Restore a deleted file
+cards = checkout
+
+[description]
+
+Oops - you deleted the "essay" file, which you worked on all night!
+
+Luckily, Git is here to help! You can use `git checkout` to restore the file!
+
+[setup]
+
+echo important > essay
+git add .
+git commit -m "Initial commit"
+echo "important content" > essay
+git commit -am "Improve essay"
+rm essay
+
+[win]
+
+# Make changes to all three files, and add all of them to the index.
+test "$(cat essay)" = "important content"

resources/cards.json

@@ -9,6 +9,11 @@
 		"command": "git checkout [commit, ref, file]",
 		"description": "Drag this card to a commit or to a branch to travel to it!\n\nAlternatively, reset changes in a local file."
 	},
+	{
+		"id": "checkout-from",
+		"command": "git checkout [commit, ref] [file]",
+		"description": "Get the file contents from the specified commits, and reset both the working directory, as well as the index, to it."
+	},
 	{
 		"id": "commit-a",
 		"command": "git commit -a",
@@ -64,6 +69,11 @@
 		"command": "git cherry-pick [commit]",
 		"description": "Repeat the specified action on top of your current timeline."
 	},
+	{
+		"id": "revert",
+		"command": "git revert [commit]",
+		"description": "Make a new commit that reverts the changes of the speicified commit."
+	},
 	{
 		"id": "bisect-start",
 		"command": "git bisect start",
@@ -114,6 +124,11 @@
 		"command": "git branch -D [ref]",
 		"description": "Delete a branch."
 	},
+	{
+		"id": "reflog",
+		"command": "git reflog [ref, head]",
+		"description": "Display a log of there the ref pointed to in the past."
+	},
 	{
 		"id": "file-new",
 		"command": "touch [string]",