commit 66c281904eba78985108b3b6f2eda48a2bdee978
Author: kaiwang.ckw <kaiwang.ckw@alibaba-inc.com>
Date:   Tue Feb 18 18:58:21 2020 +0800

    Bug #98521 Core client cannot send any query with commentary characters in hints
    
    Problem
    -------
    
    The single-line commentary characters (# or --) is valid in the hint parser.
    For example, opt_hints.test checks "select#1" as a query block identifier.
    However, the core interactive client mysql(1) can not send such queries.
    
    Analysis
    --------
    
    The problem is due to the command-line input processing loop in add_line()
    respects single-line comments in all contexts except for that of client-side
    multi-line comment. However, hint comments are designed to behave like
    regular client-side multi-line comments.
    
    Fix
    ---
    
    Make hint comment an exceptional context in single-line comment processing.
    
    Since the fix resides in the command-line input processing loop, no test file
    is provided. Instead, it is supposed to be verified by hand.

diff --git a/client/mysql.cc b/client/mysql.cc
index fde2ad60025..ad612899fc7 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -2482,6 +2482,7 @@ static bool add_line(String &buffer, char *line, size_t line_length,
       }
       buffer.length(0);
     } else if (!*ml_comment &&
+               ss_comment != SSC_HINT &&
                (!*in_string &&
                 (inchar == '#' ||
                  (inchar == '-' && pos[1] == '-' &&