Merge branch '10.1' into 10.2

1 files changed, 40 insertions, 1 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 369b2df2675..4ce0b318ed0 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -1189,7 +1189,8 @@ Item *Item_cache::safe_charset_converter(THD *thd, CHARSET_INFO *tocs)
   if (conv == example)
     return this;
   Item_cache *cache;
-  if (!conv || !(cache= new (thd->mem_root) Item_cache_str(thd, conv)))
+  if (!conv || conv->fix_fields(thd, (Item **) NULL) ||
+      !(cache= new (thd->mem_root) Item_cache_str(thd, conv)))
     return NULL; // Safe conversion is not possible, or OEM
   cache->setup(thd, conv);
   cache->fixed= false; // Make Item::fix_fields() happy
@@ -2885,6 +2886,44 @@ void Item_field::fix_after_pullout(st_select_lex *new_parent, Item **ref)
     depended_from= NULL;
   if (context)
   {
+    bool need_change= false;
+    /*
+      Suppose there are nested selects:
+
+       select_id=1
+         select_id=2
+           select_id=3  <----+
+             select_id=4    -+
+               select_id=5 --+
+
+      Suppose, pullout operation has moved anything that had select_id=4 or 5
+      in to select_id=3.
+
+      If this Item_field had a name resolution context pointing into select_lex
+      with id=4 or id=5, it needs a new name resolution context.
+
+      However, it could also be that this object is a part of outer reference:
+      Item_ref(Item_field(field in select with select_id=1))).
+      - The Item_ref object has a context with select_id=5, and so needs a new
+        name resolution context.
+      - The Item_field object has a context with select_id=1, and doesn't need
+        a new name resolution context.
+
+      So, the following loop walks from Item_field's current context upwards.
+      If we find that the select we've been pulled out to is up there, we
+      create the new name resolution context. Otherwise, we don't.
+    */
+    for (Name_resolution_context *ct= context; ct; ct= ct->outer_context)
+    {
+      if (new_parent == ct->select_lex)
+      {
+        need_change= true;
+        break;
+      }
+    }
+    if (!need_change)
+      return;
+
     Name_resolution_context *ctx= new Name_resolution_context();
     if (context->select_lex == new_parent)
     {