Bug #32124: crash if prepared statements refer to variables in the where clause

                  
The code to get read the value of a system variable was extracting its value 
on PREPARE stage and was substituting the value (as a constant) into the parse tree.
Note that this must be a reversible transformation, i.e. it must be reversed before
each re-execution.
Unfortunately this cannot be reliably done using the current code, because there are
other non-reversible source tree transformations that can interfere with this
reversible transformation.
Fixed by not resolving the value at PREPARE, but at EXECUTE (as the rest of the 
functions operate). Added a cache of the value (so that it's constant throughout
the execution of the query). Note that the cache also caches NULL values.
Updated an obsolete related test suite (variables-big) and the code to test the 
result type of system variables (as per bug 74).

mysql-test/extra/rpl_tests/rpl_insert_id.test:
  Bug #32124: removed ambiguous testcase
mysql-test/r/innodb_data_home_dir_basic.result:
  Bug #32124: fixed wrong test case
mysql-test/r/innodb_flush_method_basic.result:
  Bug #32124: fixed wrong test case
mysql-test/r/ps_11bugs.result:
  Bug #32124: test case
mysql-test/r/ssl_capath_basic.result:
  Bug #32124: fixed wrong test case
mysql-test/r/ssl_cipher_basic.result:
  Bug #32124: fixed wrong test case
mysql-test/r/variables.result:
  Bug #32124: system vars are shown as such in EXPLAIN EXTENDED, not as constants.
mysql-test/suite/rpl/r/rpl_insert_id.result:
  Bug #32124: removed ambiguous testcase
mysql-test/t/ps_11bugs.test:
  Bug #32124: test case
sql/item.cc:
  Bug #32124: placed the code to convert string to longlong or double 
  to a function (so that it can be reused)
sql/item.h:
  Bug #32124: placed the code to convert string to longlong or double 
  to a function (so that it can be reused)
sql/item_func.cc:
  Bug #32124: moved the evaluation of system variables at runtime (val_xxx).
sql/item_func.h:
  Bug #32124: moved the evaluation of system variables at runtime (val_xxx).
sql/set_var.cc:
  Bug #32124: removed the code that calculated the system variable's value 
  at PREPARE
sql/set_var.h:
  Bug #32124: removed the code that calculated the system variable's value 
  at PREPARE
tests/mysql_client_test.c:
  Bug #32124 : removed the reading of the system variable, because its max
  length is depended on the system charset and client charset and can't be
  easily calculated.

1 files changed, 4 insertions, 52 deletions

diff --git a/tests/mysql_client_test.c b/tests/mysql_client_test.c
index 6da7b3e8072..a50b009303a 100644
--- a/tests/mysql_client_test.c
+++ b/tests/mysql_client_test.c
@@ -7201,9 +7201,6 @@ static void test_field_misc()
 {
   MYSQL_STMT  *stmt;
   MYSQL_RES   *result;
-  MYSQL_BIND  my_bind[1];
-  char        table_type[NAME_LEN];
-  ulong       type_length;
   int         rc;
 
   myheader("test_field_misc");
@@ -7246,53 +7243,6 @@ static void test_field_misc()
   mysql_free_result(result);
   mysql_stmt_close(stmt);
 
-  stmt= mysql_simple_prepare(mysql, "SELECT @@table_type");
-  check_stmt(stmt);
-
-  rc= mysql_stmt_execute(stmt);
-  check_execute(stmt, rc);
-
-  bzero((char*) my_bind, sizeof(my_bind));
-  my_bind[0].buffer_type= MYSQL_TYPE_STRING;
-  my_bind[0].buffer= table_type;
-  my_bind[0].length= &type_length;
-  my_bind[0].buffer_length= NAME_LEN;
-
-  rc= mysql_stmt_bind_result(stmt, my_bind);
-  check_execute(stmt, rc);
-
-  rc= mysql_stmt_fetch(stmt);
-  check_execute(stmt, rc);
-  if (!opt_silent)
-    fprintf(stdout, "\n default table type: %s(%ld)", table_type, type_length);
-
-  rc= mysql_stmt_fetch(stmt);
-  DIE_UNLESS(rc == MYSQL_NO_DATA);
-
-  mysql_stmt_close(stmt);
-
-  stmt= mysql_simple_prepare(mysql, "SELECT @@table_type");
-  check_stmt(stmt);
-
-  result= mysql_stmt_result_metadata(stmt);
-  mytest(result);
-  DIE_UNLESS(mysql_stmt_field_count(stmt) == mysql_num_fields(result));
-
-  rc= mysql_stmt_execute(stmt);
-  check_execute(stmt, rc);
-
-  DIE_UNLESS(1 == my_process_stmt_result(stmt));
-
-  verify_prepare_field(result, 0,
-                       "@@table_type", "",   /* field and its org name */
-                       mysql_get_server_version(mysql) <= 50000 ?
-                       MYSQL_TYPE_STRING : MYSQL_TYPE_VAR_STRING,
-                       "", "",              /* table and its org name */
-                       "", type_length, 0);   /* db name, length */
-
-  mysql_free_result(result);
-  mysql_stmt_close(stmt);
-
   stmt= mysql_simple_prepare(mysql, "SELECT @@max_error_count");
   check_stmt(stmt);
 
@@ -7309,7 +7259,8 @@ static void test_field_misc()
                        "@@max_error_count", "",   /* field and its org name */
                        MYSQL_TYPE_LONGLONG, /* field type */
                        "", "",              /* table and its org name */
-                       "", 10, 0);            /* db name, length */
+                       /* db name, length */
+                       "", MY_INT64_NUM_DECIMAL_DIGITS , 0);
 
   mysql_free_result(result);
   mysql_stmt_close(stmt);
@@ -7329,7 +7280,8 @@ static void test_field_misc()
                        "@@max_allowed_packet", "", /* field and its org name */
                        MYSQL_TYPE_LONGLONG, /* field type */
                        "", "",              /* table and its org name */
-                       "", 10, 0);          /* db name, length */
+                       /* db name, length */
+                       "", MY_INT64_NUM_DECIMAL_DIGITS, 0);
 
   mysql_free_result(result);
   mysql_stmt_close(stmt);