From e814e7d79c0e6115d8a03db2515eb2761cee3516 Mon Sep 17 00:00:00 2001
From: toyomoyo <toyomoyo>
Date: Fri, 10 Aug 2007 05:22:20 +0000
Subject: [PATCH] MDL-10770, support null fields in backup/restore

---
 backup/backuplib.php  |  8 ++++++--
 backup/lib.php        |  7 ++++++-
 backup/restorelib.php | 17 +++++++++++++----
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/backup/backuplib.php b/backup/backuplib.php
index d70c6e51d09..221d846939e 100644
--- a/backup/backuplib.php
+++ b/backup/backuplib.php
@@ -444,8 +444,12 @@
 
         global $CFG;
         //Here we encode absolute links
-        $content = backup_encode_absolute_links($content);
-
+        // MDL-10770
+        if (is_null($content)) {
+            $content = '_NULL_'; 
+        } else {
+            $content = backup_encode_absolute_links($content);
+        }
         $st = start_tag($tag,$level,$endline,$attributes);
 
         $co = xml_tag_safe_content($content);
diff --git a/backup/lib.php b/backup/lib.php
index 72b562b656a..52b08753819 100644
--- a/backup/lib.php
+++ b/backup/lib.php
@@ -538,7 +538,12 @@
     //This function is used to add slashes (and decode from UTF-8 if needed)
     //It's used intensivelly when restoring modules and saving them in db
     function backup_todb ($data) {
-        return restore_decode_absolute_links(addslashes($data));
+        // MDL-10770
+        if ($data === '_NULL_') {
+            return null; 
+        } else {
+            return restore_decode_absolute_links(addslashes($data));
+        }
     }
 
     //This function is used to check that every necessary function to
diff --git a/backup/restorelib.php b/backup/restorelib.php
index 6ab234e0891..21bbcd2b04f 100644
--- a/backup/restorelib.php
+++ b/backup/restorelib.php
@@ -593,7 +593,7 @@
             $course->shortname = addslashes($course_header->course_shortname);
             $course->idnumber = addslashes($course_header->course_idnumber);
             $course->idnumber = ''; //addslashes($course_header->course_idnumber); // we don't want this at all.
-            $course->summary = restore_decode_absolute_links(addslashes($course_header->course_summary));
+            $course->summary = backup_todb($course_header->course_summary);
             $course->format = addslashes($course_header->course_format);
             $course->showgrades = addslashes($course_header->course_showgrades);
             $course->newsitems = addslashes($course_header->course_newsitems);
@@ -882,7 +882,7 @@
                 $sequence = "";
                 $section->course = $restore->course_id;
                 $section->section = $sect->number;
-                $section->summary = restore_decode_absolute_links(addslashes($sect->summary));
+                $section->summary = backup_todb($sect->summary);
                 $section->visible = $sect->visible;
                 $section->sequence = "";
                 //Now calculate the section's newid
@@ -1205,7 +1205,7 @@
                         }
                     }
                 }
-             }
+            }
         }
 
         // return if nothing to restore
@@ -2215,7 +2215,7 @@
                     $user->address = addslashes($user->address);
                     $user->city = addslashes($user->city);
                     $user->url = addslashes($user->url);
-                    $user->description = restore_decode_absolute_links(addslashes($user->description));
+                    $user->description = backup_todb($user->description);
 
                     //We need to analyse the AUTH field to recode it:
                     //   - if the field isn't set, we are in a pre 1.4 backup and we'll
@@ -3160,6 +3160,15 @@
 
         global $CFG,$restore;
 
+        // MDL-10770
+        // This function was replacing null with empty string
+        // Nullity check is added in backup_todb(), this function will no longer not be called from backup_todb() if content is null
+        // I noticed some parts of the restore code is calling this directly instead of calling backup_todb(), so just in case
+        // 3rd party mod etc are doing the same
+        if ($content === NULL) {
+            return NULL; 
+        }
+           
         //Now decode wwwroot and file.php calls
         $search = array ("$@FILEPHP@$");