Bug#33812: mysql client incorrectly parsing DELIMITER

Fix parsing of mysql client commands, especially in relation to
single-line comments when --comments was specified.

This is a little tricky, because we need to allow single-line
comments in the middle of statements, but we don't want to allow
client commands in the middle of statements. So in
comment-preservation mode, we go ahead and send single-line
comments to the server immediately when we encounter them on their
own. 

This is still slightly flawed, in that it does not handle a
single-line comment with leading spaces, followed by a client-side
command when --comment has been enabled. But this isn't a new
problem, and it is quite an edge condition. Fixing it would require
a more extensive overall of how the mysql client parses commands. 

1 files changed, 17 insertions, 32 deletions

diff --git a/client/mysql.cc b/client/mysql.cc
index 9b14f9fb3ef..20f87d5cdcd 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -1998,7 +1998,7 @@ static bool add_line(String &buffer,char *line,char *in_string,
   {
     if (!preserve_comments)
     {
-      // Skip spaces at the beggining of a statement
+      // Skip spaces at the beginning of a statement
       if (my_isspace(charset_info,inchar) && (out == line) &&
           buffer.is_empty())
         continue;
@@ -2081,37 +2081,6 @@ static bool add_line(String &buffer,char *line,char *in_string,
 	continue;
       }
     }
-    else if (!*ml_comment && !*in_string &&
-             (end_of_line - pos) >= 10 &&
-             !my_strnncoll(charset_info, (uchar*) pos, 10,
-                           (const uchar*) "delimiter ", 10))
-    {
-      // Flush previously accepted characters
-      if (out != line)
-      {
-        buffer.append(line, (uint32) (out - line));
-        out= line;
-      }
-
-      // Flush possible comments in the buffer
-      if (!buffer.is_empty())
-      {
-        if (com_go(&buffer, 0) > 0) // < 0 is not fatal
-          DBUG_RETURN(1);
-        buffer.length(0);
-      }
-
-      /*
-        Delimiter wants the get rest of the given line as argument to
-        allow one to change ';' to ';;' and back
-      */
-      buffer.append(pos);
-      if (com_delimiter(&buffer, pos) > 0)
-        DBUG_RETURN(1);
-
-      buffer.length(0);
-      break;
-    }
     else if (!*ml_comment && !*in_string && is_prefix(pos, delimiter))
     {
       // Found a statement. Continue parsing after the delimiter
@@ -2174,8 +2143,24 @@ static bool add_line(String &buffer,char *line,char *in_string,
 
       // comment to end of line
       if (preserve_comments)
+      {
+        bool started_with_nothing= !buffer.length();
+
         buffer.append(pos);
 
+        /*
+          A single-line comment by itself gets sent immediately so that
+          client commands (delimiter, status, etc) will be interpreted on
+          the next line.
+        */
+        if (started_with_nothing)
+        {
+          if (com_go(&buffer, 0) > 0)             // < 0 is not fatal
+            DBUG_RETURN(1);
+          buffer.length(0);
+        }
+      }
+
       break;
     }
     else if (!*in_string && inchar == '/' && *(pos+1) == '*' &&