Update the post-receive script to pass the previous revision to Coleslaw.

coleslaw.asd

 (defsystem #:coleslaw
   :name "coleslaw"
   :description "Flexible Lisp Blogware"
-  :version "0.9.4-dev"
+  :version "0.9.4"
   :license "BSD"
   :author "Brit Butler <redline6561@gmail.com>"
   :pathname "src/"

docs/hacking.md

 able to determine (and expose) what files just changed enables new
 functionality such as plugins that cross-post to tumblr.
 
-Git's post-receive hook is supposed to get a list of refs on $STDIN.
-A brave soul could update our post-receive script to iterate over
-those lines as shown in step 3 of this [blog post][post_receive_blog].
-There would be two primary benefits:
-
-1. We could pass the oldrev (previous revision) of the blog repo
-   to `coleslaw:main`. That could be used in conjunction with
-   `get-updated-files` to get a list of the files modified in the
-   last push. This would enable cross-posting plugins to be developed
-   as well as opening the door for incremental compilation.
-2. More seriously, **Coleslaw** currently deploys for _any_ branch
-   pushed to the bare repo. This change would also ensure that we only
-   invoke `coleslaw:main` when a push is made to the master branch.
-
 This is a cool project and the effects are far reaching. Among other
 things the existing deployment model would not work as it involves
 rebuilding the entire site. In all likelihood we would want to update
 matching the modified files. If incremental compilation is a goal,
 simply disabling the indexes may be appropriate for certain users.
 
-[post_receive_blog]: http://codeshal.tumblr.com/post/927943180/git-post-receive-hook-that-submits-code-to-review-board
 [post_receive_hook]: https://github.com/redline6561/coleslaw/blob/master/examples/example.post-receive
 [closure_template]: https://github.com/archimag/cl-closure-template
 [api_docs]: https://github.com/redline6561/coleslaw/blob/master/docs/plugin-api.md

examples/example.post-receive

 
 git clone $GIT_REPO $TMP_GIT_CLONE || exit 1
 
-if [ $LISP = sbcl ]; then
-    sbcl --eval "(ql:quickload 'coleslaw)" \
-         --eval "(coleslaw:main \"$TMP_GIT_CLONE\")" \
-         --eval "(coleslaw::exit)"
-elif [ $LISP = ccl ]; then
-    echo "(ql:quickload 'coleslaw)(coleslaw:main \"$TMP_GIT_CLONE\")(coleslaw::exit)" | ccl -b
-else
-    exit 1
-fi
+while read oldrev newrev refname; do
+    if [ $refname = "refs/heads/master" ]; then
+        echo -e "\n  Master updated. Running coleslaw...\n"
+        if [ $LISP = sbcl ]; then
+            sbcl --eval "(ql:quickload 'coleslaw)" \
+                 --eval "(coleslaw:main \"$TMP_GIT_CLONE\" \"$oldrev\")" \
+                 --eval "(coleslaw::exit)"
+        elif [ $LISP = ccl ]; then
+            ccl -e "(ql:quickload 'coleslaw) (coleslaw:main \"$TMP_GIT_CLONE\" \"$oldrev\") (coleslaw::exit)"
+        else
+            exit 1
+        fi
+    fi
+done
 
 rm -rf $TMP_GIT_CLONE
 exit

src/coleslaw.lisp

 (in-package :coleslaw)
 
-(defun main (&optional (repo-dir ""))
-  "Load the user's config file, then compile and deploy the site."
+(defun main (&optional (repo-dir "") oldrev)
+  "Load the user's config file, then compile and deploy the site. Optionally,
+REPO-DIR is the location of the blog repo and OLDREV is the revision prior to
+the last push."
   (load-config repo-dir)
   (load-content)
   (compile-theme (theme *config*))

src/util.lisp

 
 (defun get-updated-files (revision)
   "Return a plist of (file-status file-name) for files that were changed
-in git since REVISION."
-  (with-current-directory (repo *config*)
-    (flet ((split-on-whitespace (str)
-             (cl-ppcre:split "\\s+" str)))
-      (let ((cmd (format nil "git diff --name-status ~A HEAD" revision)))
-        (mapcar #'split-on-whitespace (inferior-shell:run/lines cmd))))))
+in the git repo since REVISION."
+  (flet ((split-on-whitespace (str)
+           (cl-ppcre:split "\\s+" str)))
+    (let ((cmd (format nil "git diff --name-status ~A HEAD" revision)))
+      (mapcar #'split-on-whitespace (inferior-shell:run/lines cmd)))))