From 8304e6b74bd8a8ebac03ef0db9c78b49779ef08f Mon Sep 17 00:00:00 2001
From: Javier Olaechea <pirata@gmail.com>
Date: Sun, 17 Aug 2014 16:46:57 -0500
Subject: [PATCH] More robust directory changing

     - Doesn't fail when the directory is missing a trailing '/'
     - When directory doesn't exist it signals an informative
       condition.
---
 src/packages.lisp |  4 +++-
 src/util.lisp     | 10 +++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/packages.lisp b/src/packages.lisp
index dd6dccd..a9a3786 100644
--- a/src/packages.lisp
+++ b/src/packages.lisp
@@ -8,7 +8,9 @@
   (:import-from :closure-template #:compile-template)
   (:import-from :local-time #:format-rfc1123-timestring)
   (:import-from :uiop #:getcwd
-                      #:chdir)
+                      #:chdir
+                      #:ensure-directory-pathname
+                      #:directory-exists-p)
   (:export #:main
            #:preview
            #:*config*
diff --git a/src/util.lisp b/src/util.lisp
index b9c76a0..1811bde 100644
--- a/src/util.lisp
+++ b/src/util.lisp
@@ -30,9 +30,17 @@ BODY on files that match the given extension."
                                         #',extension-p
                                         (constantly t))))))
 
+(define-condition directory-does-not-exist (error)
+  ((directory :initarg dir :reader dir))
+  (:report (lambda (c stream)
+             (format stream "The directory '~A' does not exist" (dir c)))))
+
 (defun (setf getcwd) (path)
   "Change the operating system's current directory to PATH."
-  (chdir path)
+  (setf path (ensure-directory-pathname path))
+  (or (and (directory-exists-p path)
+           (chdir path))
+      (error 'directory-does-not-exist :dir path))
   path)
 
 (defmacro with-current-directory (path &body body)