BUG#58985: Assertion tab->quick->index != 64 failed in make_join_select()

           in sql_select.cc

Follow-up patch. Add sanity check for quick select when it is
decided that it should be used.

sql/opt_range.h:
  Add is_valid() to QUICK_SELECT*
sql/sql_select.cc:
  Add sanity check for quick select when it is decided that it should be used.

sql/opt_range.h

@@ -336,6 +336,13 @@ public:
   */
   virtual bool is_keys_used(const MY_BITMAP *fields);
 
+  /**
+    Simple sanity check that the quick select has been set up
+    correctly. Function is overridden by quick selects that merge
+    indices.
+   */
+  virtual bool is_valid() { return index != MAX_KEY; };
+
   /*
     rowid of last row retrieved by this quick select. This is used only when
     doing ROR-index_merge selects
@@ -556,6 +563,22 @@ public:
 
   bool clustered_pk_range() { return test(pk_quick_select); }
 
+  virtual bool is_valid()
+  {
+    List_iterator_fast<QUICK_RANGE_SELECT> it(quick_selects);
+    QUICK_RANGE_SELECT *quick;
+    bool valid= true;
+    while ((quick= it++))
+    {
+      if (!quick->is_valid())
+      {
+        valid= false;
+        break;
+      }
+    }
+    return valid;
+  }
+
   /* used to get rows collected in Unique */
   READ_RECORD read_record;
 };
@@ -608,6 +631,22 @@ public:
   */
   List<QUICK_RANGE_SELECT> quick_selects;
 
+  virtual bool is_valid()
+  {
+    List_iterator_fast<QUICK_RANGE_SELECT> it(quick_selects);
+    QUICK_RANGE_SELECT *quick;
+    bool valid= true;
+    while ((quick= it++))
+    {
+      if (!quick->is_valid())
+      {
+        valid= false;
+        break;
+      }
+    }
+    return valid;
+  }
+
   /*
     Merged quick select that uses Clustered PK, if there is one. This quick
     select is not used for row retrieval, it is used for row retrieval.
@@ -658,6 +697,22 @@ public:
 
   List<QUICK_SELECT_I> quick_selects; /* Merged quick selects */
 
+  virtual bool is_valid()
+  {
+    List_iterator_fast<QUICK_SELECT_I> it(quick_selects);
+    QUICK_SELECT_I *quick;
+    bool valid= true;
+    while ((quick= it++))
+    {
+      if (!quick->is_valid())
+      {
+        valid= false;
+        break;
+      }
+    }
+    return valid;
+  }
+
   QUEUE queue;    /* Priority queue for merge operation */
   MEM_ROOT alloc; /* Memory pool for this and merged quick selects data. */
 

sql/sql_select.cc

@@ -6504,6 +6504,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
               ((tab->type != JT_CONST && tab->type != JT_REF) ||
                (uint)tab->ref.key == tab->quick->index))
           {
+            DBUG_ASSERT(tab->quick->is_valid());
 	    sel->quick=tab->quick;		// Use value from get_quick_...
 	    sel->quick_keys.clear_all();
 	    sel->needed_reg.clear_all();