From aa0aae272bf1160becc45d2343bb990489009bb1 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Fri, 31 Aug 2012 23:43:50 +0200
Subject: [PATCH] Fix #835: el-get-update treat prop removal now

Use the new source or abort if non-whitelisted properties are changed.

fixes #835
---
 el-get-status.el | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/el-get-status.el b/el-get-status.el
index 38d88967..8d6f500e 100644
--- a/el-get-status.el
+++ b/el-get-status.el
@@ -238,6 +238,22 @@ are not."
         else do (setq disallowed (plist-put disallowed k v))
         finally return (list update disallowed)))
 
+(defun el-get-non-whitelisted-properties-changed-p (old-source new-source)
+  "Test if non-whitelisted properties are changed."
+  (loop for k in (set-difference
+                  (remove-duplicates
+                   (append (loop for (k _) on old-source by 'cddr collect k)
+                           (loop for (k _) on new-source by 'cddr collect k)))
+                  el-get-status-recipe-update-whitelist)
+        for in-old-p = (plist-member old-source k)
+        for in-new-p = (plist-member new-source k)
+        for old-val  = (plist-get    old-source k)
+        for new-val  = (plist-get    new-source k)
+        if (or (and (not in-old-p) in-new-p)  ; added
+               (and (not in-new-p) in-old-p)  ; removed
+               (not (equal old-val new-val))) ; changed
+        return t))
+
 (defun* el-get-merge-properties-into-status (package-or-source
                                              &optional package-status-alist
                                              &key noerror skip-non-updatable)
@@ -291,7 +307,7 @@ non-whitelisted changes, and no error will be raised.
                   append (list k v))))
     (destructuring-bind (update disallowed)
         (el-get-classify-new-properties cached-recipe source)
-      (when disallowed
+      (when (el-get-non-whitelisted-properties-changed-p cached-recipe source)
         ;; Emit a verbose message if `noerror' is t (but still quit
         ;; the function).
         (funcall (if noerror 'el-get-verbose-message 'error)
@@ -307,11 +323,9 @@ Maybe you should use `el-get-update' or `el-get-reinstall' on %s instead?"
                  (el-get-source-name cached-recipe))
         (return-from el-get-merge-properties-into-status))
       (when update
-        (loop for (k v) on update by 'cddr
-              do (plist-put cached-recipe k v))
         (if save-to-file
-            (el-get-save-package-status package "installed" cached-recipe)
+            (el-get-save-package-status package "installed" source)
           (plist-put (cdr (assq package package-status-alist))
-                     'recipe cached-recipe))))))
+                     'recipe source))))))
 
 (provide 'el-get-status)