Bug #27653: Temp table can't be created if lower_case_table_names=1 and

            tmpdir has uppercase

Fix: don't convert mysql_tmpdir to lower case when building the path to a
temporary table

mysql-test/include/have_lowercase1.inc

+--require r/lowercase1.require
+--disable_query_log
+show variables like 'lower_case_table_names';
+--enable_query_log

mysql-test/r/lowercase1.require

+Variable_name	Value
+lower_case_table_names	1

mysql-test/r/lowercase_mixed_tmpdir.result

+drop table if exists t1;
+create table t1 (id int) engine=myisam;
+insert into t1 values (1);
+create temporary table t2 select * from t1;
+drop temporary table t2;
+drop table t1;

mysql-test/t/lowercase_mixed_tmpdir-master.opt

+--lower-case-table-names=1
+--tmpdir=$MYSQLTEST_VARDIR/tmp/MixedCase

mysql-test/t/lowercase_mixed_tmpdir-master.sh

+# This test requires a non-lowercase tmpdir directory on a case-sensitive
+# filesystem.
+
+d="$MYSQLTEST_VARDIR/tmp/MixedCase"
+test -d "$d" || mkdir "$d"
+rm -f "$d"/*

mysql-test/t/lowercase_mixed_tmpdir.test

+--source include/have_case_sensitive_file_system.inc
+--source include/have_lowercase1.inc
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+create table t1 (id int) engine=myisam;
+insert into t1 values (1);
+create temporary table t2 select * from t1;
+drop temporary table t2;
+drop table t1;

sql/sql_table.cc

@@ -42,6 +42,7 @@ static int copy_data_between_tables(TABLE *from,TABLE *to,
 static bool prepare_blob_field(THD *thd, create_field *sql_field);
 static bool check_engine(THD *thd, const char *table_name,
                          enum db_type *new_engine);                             
+static void set_tmp_file_path(char *buf, size_t bufsize, THD *thd);
 
 
 /*
@@ -1681,11 +1682,7 @@ bool mysql_create_table(THD *thd,const char *db, const char *table_name,
       /* Check if table exists */
   if (create_info->options & HA_LEX_CREATE_TMP_TABLE)
   {
-    my_snprintf(path, sizeof(path), "%s%s%lx_%lx_%x%s",
-		mysql_tmpdir, tmp_file_prefix, current_pid, thd->thread_id,
-		thd->tmp_table++, reg_ext);
-    if (lower_case_table_names)
-      my_casedn_str(files_charset_info, path);
+    set_tmp_file_path(path, sizeof(path), thd);
     create_info->table_options|=HA_CREATE_DELAY_KEY_WRITE;
   }
   else  
@@ -2801,11 +2798,7 @@ bool mysql_create_like_table(THD* thd, TABLE_LIST* table,
   {
     if (find_temporary_table(thd, db, table_name))
       goto table_exists;
-    my_snprintf(dst_path, sizeof(dst_path), "%s%s%lx_%lx_%x%s",
-		mysql_tmpdir, tmp_file_prefix, current_pid,
-		thd->thread_id, thd->tmp_table++, reg_ext);
-    if (lower_case_table_names)
-      my_casedn_str(files_charset_info, dst_path);
+    set_tmp_file_path(dst_path, sizeof(dst_path), thd);
     create_info->table_options|= HA_CREATE_DELAY_KEY_WRITE;
   }
   else
@@ -4319,3 +4312,16 @@ static bool check_engine(THD *thd, const char *table_name,
   }
   return FALSE;
 }
+
+static void set_tmp_file_path(char *buf, size_t bufsize, THD *thd)
+{
+  char *p= strnmov(buf, mysql_tmpdir, bufsize);
+  my_snprintf(p, bufsize - (p - buf), "%s%lx_%lx_%x%s",
+              tmp_file_prefix, current_pid,
+              thd->thread_id, thd->tmp_table++, reg_ext);
+  if (lower_case_table_names)
+  {
+    /* Convert all except tmpdir to lower case */
+    my_casedn_str(files_charset_info, p);
+  }
+}