Bug#32757: hang with sql_mode set when setting some global variables

If setting a system-variable provided by a plug-in failed, no OK or
error was sent in some cases, hanging the client. We now send an error
in the case from the ticket (integer-argument out of range in STRICT
mode). We also provide a semi-generic fallback message for possible
future cases like this where an error is signalled, but no message is
sent to the client. The error/warning handling is unified so it's the
same again for variables provided by plugins and those in the server
proper.

1 files changed, 14 insertions, 0 deletions

diff --git a/storage/example/ha_example.cc b/storage/example/ha_example.cc
index 6d9f4841e06..604722c3c8c 100644
--- a/storage/example/ha_example.cc
+++ b/storage/example/ha_example.cc
@@ -849,6 +849,7 @@ struct st_mysql_storage_engine example_storage_engine=
 { MYSQL_HANDLERTON_INTERFACE_VERSION };
 
 static ulong srv_enum_var= 0;
+static ulong srv_ulong_var= 0;
 
 const char *enum_var_names[]=
 {
@@ -871,8 +872,21 @@ static MYSQL_SYSVAR_ENUM(
   0,                              // def
   &enum_var_typelib);             // typelib
 
+static MYSQL_SYSVAR_ULONG(
+  ulong_var,
+  srv_ulong_var,
+  PLUGIN_VAR_RQCMDARG,
+  "0..1000",
+  NULL,
+  NULL,
+  8,
+  0,
+  1000,
+  0);
+
 static struct st_mysql_sys_var* example_system_variables[]= {
   MYSQL_SYSVAR(enum_var),
+  MYSQL_SYSVAR(ulong_var),
   NULL
 };