Proposed fix for Bug#4026 "Microseconds part of TIME/DATETIME types

is broken (prepared statements)": fixed date handling in many places 
of prepared statements code.


libmysql/libmysql.c:
  Fix for Bug#4026:
  - now buffer_length is defined for any buffer type. Network buffer 
    preallocation cleaned up.
  - added constants for maximum buffer sizes necessary for MYSQL_TYPE_DATE,
    MYSQL_TYPE_TIME, MYSQL_TYPE_DATETIME types.
  - TIME/DATETIME packing/unpacking functions fixed 
  - now result set metadata is always updated from fields sent to COM_EXECUTE.
    This is necessary to make 'SELECT ?' queries work without conversions.
sql/item.cc:
  - added implementatoin of Item_param::get_date
sql/item.h:
  - added enum_field_types Item_param::param_type. First step for proper
    handling of placeholders.
  - added get_date() implementation to prevent date -> string -> date 
    conversions when MYSQL_TYPE_DATE/DATETIME parameter is used in temporal 
    context.
sql/protocol.cc:
  Fix for Bug#4026:
  - PACKET_BUFFET_EXTRA_ALLOC -> PACKET_BUFFER_EXTRA_ALLOC.
    The define itself was moved to .cc as it's used only in protocol.cc
  - fixed Protocol_prep::store_time() call.
sql/protocol.h:
  - PACKET_BUFFER_EXTRA_ALLOC moved to protocol.cc
sql/sql_prepare.cc:
  Fix for Bug#4026:
  - MYSQL_TYPE_TIME/DATETIME handling fixed.
  - added initialization for Item_param::param_type in 
    setup_one_conversion_function
tests/client_test.c:
  Test case for Bug#4026

5 files changed, 49 insertions, 27 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 7db1a448e55..d85d70c69ab 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -629,6 +629,7 @@ Item_param::Item_param(unsigned pos_in_query_arg) :
   state(NO_VALUE),
   item_result_type(STRING_RESULT),
   item_type(STRING_ITEM),
+  param_type(MYSQL_TYPE_STRING),
   pos_in_query(pos_in_query_arg),
   set_param_func(default_set_param_func)
 {
@@ -808,6 +809,17 @@ bool Item_param::get_time(TIME *res)
 }
 
 
+bool Item_param::get_date(TIME *res, uint fuzzydate)
+{
+  if (state == TIME_VALUE)
+  {
+    *res= value.time;
+    return 0;
+  }
+  return Item::get_date(res, fuzzydate);
+}
+
+
 double Item_param::val() 
 {
   switch (state) {
diff --git a/sql/item.h b/sql/item.h
index 885a34dce81..e4c134842b9 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -465,6 +465,16 @@ public:
   /* Cached values for virtual methods to save us one switch.  */
   enum Item_result item_result_type;
   enum Type item_type;
+
+  /*
+    Used when this item is used in a temporary table.
+    This is NOT placeholder metadata sent to client, as this value
+    is assigned after sending metadata (in setup_one_conversion_function).
+    For example in case of 'SELECT ?' you'll get MYSQL_TYPE_STRING both
+    in result set and placeholders metadata, no matter what type you will
+    supply for this placeholder in mysql_stmt_execute.
+  */
+  enum enum_field_types param_type;
   /*         
     Offset of placeholder inside statement text. Used to create
     no-placeholders version of this statement for the binary log.
@@ -475,12 +485,13 @@ public:
 
   enum Item_result result_type () const { return item_result_type; }
   enum Type type() const { return item_type; }
-  enum_field_types field_type() const { return MYSQL_TYPE_STRING; }
+  enum_field_types field_type() const { return param_type; }
 
   double val();
   longlong val_int();
   String *val_str(String*);
   bool get_time(TIME *tm);
+  bool get_date(TIME *tm, uint fuzzydate);
   int  save_in_field(Field *field, bool no_conversions);
 
   void set_null();
diff --git a/sql/protocol.cc b/sql/protocol.cc
index 44fc4eff9ad..7738349c742 100644
--- a/sql/protocol.cc
+++ b/sql/protocol.cc
@@ -26,6 +26,8 @@
 #include "mysql_priv.h"
 #include <stdarg.h>
 
+static const unsigned int PACKET_BUFFER_EXTRA_ALLOC= 1024;
+
 #ifndef EMBEDDED_LIBRARY
 bool Protocol::net_store_data(const char *from, uint length)
 #else
@@ -687,7 +689,7 @@ bool Protocol_simple::store_null()
 #endif
   char buff[1];
   buff[0]= (char)251;
-  return packet->append(buff, sizeof(buff), PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, sizeof(buff), PACKET_BUFFER_EXTRA_ALLOC);
 }
 #endif
 
@@ -990,7 +992,7 @@ bool Protocol_prep::store_tiny(longlong from)
   char buff[1];
   field_pos++;
   buff[0]= (uchar) from;
-  return packet->append(buff, sizeof(buff), PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, sizeof(buff), PACKET_BUFFER_EXTRA_ALLOC);
 }
 
 
@@ -1002,7 +1004,7 @@ bool Protocol_prep::store_short(longlong from)
         field_types[field_pos] == MYSQL_TYPE_YEAR);
 #endif
   field_pos++;
-  char *to= packet->prep_append(2, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(2, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   int2store(to, (int) from);
@@ -1018,7 +1020,7 @@ bool Protocol_prep::store_long(longlong from)
 	      field_types[field_pos] == MYSQL_TYPE_LONG);
 #endif
   field_pos++;
-  char *to= packet->prep_append(4, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(4, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   int4store(to, from);
@@ -1033,7 +1035,7 @@ bool Protocol_prep::store_longlong(longlong from, bool unsigned_flag)
 	      field_types[field_pos] == MYSQL_TYPE_LONGLONG);
 #endif
   field_pos++;
-  char *to= packet->prep_append(8, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(8, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   int8store(to, from);
@@ -1048,7 +1050,7 @@ bool Protocol_prep::store(float from, uint32 decimals, String *buffer)
 	      field_types[field_pos] == MYSQL_TYPE_FLOAT);
 #endif
   field_pos++;
-  char *to= packet->prep_append(4, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(4, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   float4store(to, from);
@@ -1063,7 +1065,7 @@ bool Protocol_prep::store(double from, uint32 decimals, String *buffer)
 	      field_types[field_pos] == MYSQL_TYPE_DOUBLE);
 #endif
   field_pos++;
-  char *to= packet->prep_append(8, PACKET_BUFFET_EXTRA_ALLOC);
+  char *to= packet->prep_append(8, PACKET_BUFFER_EXTRA_ALLOC);
   if (!to)
     return 1;
   float8store(to, from);
@@ -1112,7 +1114,7 @@ bool Protocol_prep::store(TIME *tm)
   else
     length=0;
   buff[0]=(char) length;			// Length is stored first
-  return packet->append(buff, length+1, PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, length+1, PACKET_BUFFER_EXTRA_ALLOC);
 }
 
 bool Protocol_prep::store_date(TIME *tm)
@@ -1129,7 +1131,7 @@ bool Protocol_prep::store_time(TIME *tm)
   DBUG_ASSERT(field_types == 0 ||
 	      field_types[field_pos] == MYSQL_TYPE_TIME);
 #endif
-  char buff[15],*pos;
+  char buff[13], *pos;
   uint length;
   field_pos++;
   pos= buff+1;
@@ -1140,13 +1142,13 @@ bool Protocol_prep::store_time(TIME *tm)
   pos[7]= (uchar) tm->second;
   int4store(pos+8, tm->second_part);
   if (tm->second_part)
-    length=11;
+    length=12;
   else if (tm->hour || tm->minute || tm->second || tm->day)
     length=8;
   else
     length=0;
   buff[0]=(char) length;			// Length is stored first
-  return packet->append(buff, length+1, PACKET_BUFFET_EXTRA_ALLOC);
+  return packet->append(buff, length+1, PACKET_BUFFER_EXTRA_ALLOC);
 }
 
 #ifdef EMBEDDED_LIBRARY
diff --git a/sql/protocol.h b/sql/protocol.h
index 41885ec9f1f..43230983db7 100644
--- a/sql/protocol.h
+++ b/sql/protocol.h
@@ -18,7 +18,6 @@
 #pragma interface			/* gcc class implementation */
 #endif
 
-#define PACKET_BUFFET_EXTRA_ALLOC	1024
 
 class i_string;
 class THD;
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 1713c81a096..ab181e02735 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -332,20 +332,19 @@ static void set_param_time(Item_param *param, uchar **pos, ulong len)
   {
     uchar *to= *pos;
     TIME  tm;
-    
-    /* TODO: why length is compared with 8 here? */
-    tm.second_part= (length > 8 ) ? (ulong) sint4korr(to+7): 0;
 
+    tm.neg= (bool) to[0];
+    day= (uint) sint4korr(to+1);
     /*
       Note, that though ranges of hour, minute and second are not checked
       here we rely on them being < 256: otherwise
       we'll get buffer overflow in make_{date,time} functions,
       which are called when time value is converted to string.
     */
-    day= (uint) sint4korr(to+1);
     tm.hour=   (uint) to[5] + day * 24;
     tm.minute= (uint) to[6];
     tm.second= (uint) to[7];
+    tm.second_part= (length > 8) ? (ulong) sint4korr(to+8) : 0;
     if (tm.hour > 838)
     {
       /* TODO: add warning 'Data truncated' here */
@@ -354,7 +353,6 @@ static void set_param_time(Item_param *param, uchar **pos, ulong len)
       tm.second= 59;
     }
     tm.day= tm.year= tm.month= 0;
-    tm.neg= (bool)to[0];
 
     param->set_time(&tm, TIMESTAMP_TIME,
                     MAX_TIME_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
@@ -365,14 +363,16 @@ static void set_param_time(Item_param *param, uchar **pos, ulong len)
 static void set_param_datetime(Item_param *param, uchar **pos, ulong len)
 {
   uint length;
- 
+
   if ((length= get_param_length(pos, len)) >= 4)
   {
     uchar *to= *pos;
     TIME  tm;
-    
-    tm.second_part= (length > 7 ) ? (ulong) sint4korr(to+7): 0;
-    
+
+    tm.neg=    0;
+    tm.year=   (uint) sint2korr(to);
+    tm.month=  (uint) to[2];
+    tm.day=    (uint) to[3];
     /*
       Note, that though ranges of hour, minute and second are not checked
       here we rely on them being < 256: otherwise
@@ -386,11 +386,8 @@ static void set_param_datetime(Item_param *param, uchar **pos, ulong len)
     }
     else
       tm.hour= tm.minute= tm.second= 0;
-    
-    tm.year=   (uint) sint2korr(to);
-    tm.month=  (uint) to[2];
-    tm.day=    (uint) to[3];
-    tm.neg=    0;
+
+    tm.second_part= (length > 7) ? (ulong) sint4korr(to+7) : 0;
 
     param->set_time(&tm, TIMESTAMP_DATETIME, 
                     MAX_DATETIME_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
@@ -585,6 +582,7 @@ static void setup_one_conversion_function(THD *thd, Item_param *param,
       param->item_result_type= STRING_RESULT;
     }
   }
+  param->param_type= (enum enum_field_types) param_type;
 }
 
 #ifndef EMBEDDED_LIBRARY