From 8914508a4b3af9891011b6891efedcb9159fad62 Mon Sep 17 00:00:00 2001
From: stronk7 <stronk7>
Date: Sat, 21 Oct 2006 18:19:47 +0000
Subject: [PATCH] Prevent add_field() to work if we are adding one not null
 field to one non-empty table without specifying its default value.

Merged from MOODLE_17_STABLE
---
 lib/ddllib.php | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/ddllib.php b/lib/ddllib.php
index ea316768e9..5166994653 100644
--- a/lib/ddllib.php
+++ b/lib/ddllib.php
@@ -678,6 +678,12 @@ function add_field($table, $field, $continue=true, $feedback=true) {
         return true;
     }
 
+/// If NOT NULL and no default given, check the table is empty
+    if ($field->getNotNull() && $field->getDefault() === NULL && count_records($table->getName())) {
+        debugging('Field ' . $field->getName() . ' cannot be added. Not null fields added to non empty tables require default value. Create skipped', DEBUG_DEVELOPER);
+         return true;
+    }
+
     if(!$sqlarr = $table->getAddFieldSQL($CFG->dbtype, $CFG->prefix, $field, false)) {
         return true; //Empty array = nothing to do = no error
     }
-- 
2.39.5