Merge 10.2 into 10.3

sql/field.h

@@ -1,7 +1,7 @@
 #ifndef FIELD_INCLUDED
 #define FIELD_INCLUDED
 /* Copyright (c) 2000, 2015, Oracle and/or its affiliates.
-   Copyright (c) 2008, 2019, MariaDB Corporation.
+   Copyright (c) 2008, 2020, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -825,6 +825,19 @@ public:
     DBUG_ASSERT(ls.length < UINT_MAX32);
     return store(ls.str, (uint) ls.length, cs);
   }
+
+#ifdef HAVE_valgrind_or_MSAN
+  /**
+    Mark unused memory in the field as defined. Mainly used to ensure
+    that if we write full field to disk (for example in
+    Count_distinct_field::add(), we don't write unitalized data to
+    disk which would confuse valgrind or MSAN.
+  */
+  virtual void mark_unused_memory_as_defined() {}
+#else
+  void mark_unused_memory_as_defined() {}
+#endif
+
   virtual double val_real(void)=0;
   virtual longlong val_int(void)=0;
   /*
@@ -3451,6 +3464,9 @@ public:
   }
   int  store(const char *to,size_t length,CHARSET_INFO *charset);
   using Field_str::store;
+#ifdef HAVE_valgrind_or_MSAN
+  void mark_unused_memory_as_defined();
+#endif
   double val_real(void);
   longlong val_int(void);
   String *val_str(String*,String *);