Bug #19147: mysqlshow INFORMATION_SCHEMA does not work

  When a wildcard database name is given the mysqlshow, but that wildcard
  matches one database *exactly* (it contains the wildcard character), we
  list the contents of that database instead of just listing the database
  name as matching the wildcard. Probably the most common instance of users
  encountering this behavior would be with "mysqlshow information_schema".


client/mysqlshow.c:
  Add special handling for listing a single database that has a name that
  looked like it contained wildcards. In this case, we just go ahead and list
  the contents of the database, since there is a very high probability that is
  what the user really wanted to do. (For example, 'mysqlshow INFORMATION_SCHEMA'
  will show the I_S tables instead of just the I_S database.)
mysql-test/r/mysqlshow.result:
  Add new results
mysql-test/t/mysqlshow.test:
  Add new regression test

1 files changed, 25 insertions, 2 deletions

diff --git a/client/mysqlshow.c b/client/mysqlshow.c
index d090495ff81..40405c53565 100644
--- a/client/mysqlshow.c
+++ b/client/mysqlshow.c
@@ -344,7 +344,7 @@ list_dbs(MYSQL *mysql,const char *wild)
   char query[255];
   MYSQL_FIELD *field;
   MYSQL_RES *result;
-  MYSQL_ROW row, rrow;
+  MYSQL_ROW row= NULL, rrow;
 
   if (!(result=mysql_list_dbs(mysql,wild)))
   {
@@ -352,6 +352,26 @@ list_dbs(MYSQL *mysql,const char *wild)
 	    mysql_error(mysql));
     return 1;
   }
+
+  /*
+    If a wildcard was used, but there was only one row and it's name is an
+    exact match, we'll assume they really wanted to see the contents of that
+    database. This is because it is fairly common for database names to
+    contain the underscore (_), like INFORMATION_SCHEMA.
+   */
+  if (wild && mysql_num_rows(result) == 1)
+  {
+    row= mysql_fetch_row(result);
+    if (!my_strcasecmp(&my_charset_latin1, row[0], wild))
+    {
+      mysql_free_result(result);
+      if (opt_status)
+        return list_table_status(mysql, wild, NULL);
+      else
+        return list_tables(mysql, wild, NULL);
+    }
+  }
+
   if (wild)
     printf("Wildcard: %s\n",wild);
 
@@ -368,7 +388,8 @@ list_dbs(MYSQL *mysql,const char *wild)
   else
     print_header(header,length,"Tables",6,"Total Rows",12,NullS);
 
-  while ((row = mysql_fetch_row(result)))
+  /* The first row may have already been read up above. */
+  while (row || (row= mysql_fetch_row(result)))
   {
     counter++;
 
@@ -422,6 +443,8 @@ list_dbs(MYSQL *mysql,const char *wild)
       print_row(row[0],length,tables,6,NullS);
     else
       print_row(row[0],length,tables,6,rows,12,NullS);
+
+    row= NULL;
   }
 
   print_trailer(length,