From d43f31a79306c2a5a333981f96882c7e24e871f3 Mon Sep 17 00:00:00 2001
From: Shrikant Sharat <shrikantsharat.k@gmail.com>
Date: Sun, 12 Aug 2012 20:15:10 +0530
Subject: [PATCH] Initial implementation of antigen-revert command.

Use this command to revert an `antigen-update`.
---
 antigen.zsh           | 22 +++++++++++++++++++
 tests/revert-update.t | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 tests/revert-update.t

diff --git a/antigen.zsh b/antigen.zsh
index 0350ed3..f766bf5 100644
--- a/antigen.zsh
+++ b/antigen.zsh
@@ -97,16 +97,38 @@ antigen-bundles () {
 
 antigen-update () {
     # Update your bundles, i.e., `git pull` in all the plugin repos.
+
+    date > $ADOTDIR/revert-info
+
     -antigen-echo-record |
         awk '{print $1}' |
         sort -u |
         while read url; do
             echo "**** Pulling $url"
+            (dir="$(-antigen-get-clone-dir "$url")"
+                echo -n "$dir:"
+                cd "$dir"
+                git rev-parse HEAD) >> $ADOTDIR/revert-info
             -antigen-ensure-repo "$url" --update --verbose
             echo
         done
 }
 
+antigen-revert () {
+    if ! [[ -f $ADOTDIR/revert-info ]]; then
+        echo 'No revert information available. Cannot revert.' >&2
+    fi
+
+    cat $ADOTDIR/revert-info | sed '1!p' | while read line; do
+        dir="$(echo "$line" | cut -d: -f1)"
+        git --git-dir="$dir/.git" --work-tree="$dir" \
+            checkout "$(echo "$line" | cut -d: -f2)" 2> /dev/null
+    done
+
+    echo "Reverted to state before running -update on $(
+            cat $ADOTDIR/revert-info | sed -n 1p)."
+}
+
 -antigen-get-clone-dir () {
     # Takes a repo url and gives out the path that this url needs to be cloned
     # to. Doesn't actually clone anything.
diff --git a/tests/revert-update.t b/tests/revert-update.t
new file mode 100644
index 0000000..2974de5
--- /dev/null
+++ b/tests/revert-update.t
@@ -0,0 +1,61 @@
+Load and test plugin.
+
+  $ antigen-bundle $PLUGIN_DIR
+  Cloning into '.+?'\.\.\. (re)
+  done.
+  $ hehe
+  hehe
+
+Save the current HEAD of the plugin.
+
+  $ old_version="$(pg rev-parse HEAD)"
+
+Modify the plugin.
+
+  $ cat > $PLUGIN_DIR/aliases.zsh <<EOF
+  > alias hehe='echo hehe, updated'
+  > EOF
+  $ pg commit -am 'Updated message'
+  \[master [a-f0-9]{7}\] Updated message (re)
+   1 file changed, 1 insertion(+), 1 deletion(-)
+
+Save the new HEAD of the plugin.
+
+  $ new_version="$(pg rev-parse HEAD)"
+
+Define a convenience function to get the current version.
+
+  $ current-version () {(cd dot-antigen/repos/* && git rev-parse HEAD)}
+
+Confirm we currently have the old version.
+
+  $ [[ $(current-version) == $old_version ]]
+
+Run antigen's update.
+
+  $ antigen-update
+  **** Pulling */test-plugin (glob)
+  From */test-plugin (glob)
+     ???????..???????  master     -> origin/master (glob)
+  Updating ???????..??????? (glob)
+  Fast-forward
+   aliases.zsh |    2 +-
+   1 file changed, 1 insertion(+), 1 deletion(-)
+  Updated from ??????? to ???????. (glob)
+  ??????? Updated message (glob)
+   aliases.zsh |    2 +-
+   1 file changed, 1 insertion(+), 1 deletion(-)
+  
+
+Confirm we have the new version.
+
+  $ [[ $(current-version) == $new_version ]]
+
+Run update again, with no changes in the origin repo.
+
+  $ antigen-revert
+  Reverted to state before running -update on *. (glob)
+
+Confirm we have the old version again.
+
+  $ [[ $(current-version) == $old_version ]]
-- 
2.0.0