Newlines get unescaped on their way to the database.

[schuler.steffen]

As reported by steffen schuler:

If one pastes code with the literal ``\n'' inside the code or
in the header, then the pasted output is different.

Reproduction Steps

1. Navigate to  http://awkpaste.blisted.org/
2. Enter the following paste:

   # An escaped linefeed
   print "\n"
   
   # An escaped escape and an n.
   print "\\\n"
   
   # An escaped carriage return
   print "\r"
   
   # An escaped esacpe and an r.
   print "\\r"
   
   # escaped escape
   print "\\"
   
   # End of line that's escaped.
   print "This string is waaaaaaay too large for me to possibly be able " \
         "to fit it in a single line"
   
   # Some accidental backslashes: \\
   # Four backslashes and an n: \\\\n
   

3. Observe output.
4. Click paste-id link at top left corner of page.

Expected

The paste output from the paste-id link is the same as that returned by the form submission.

Observed

The text \n is translated into a newline in the paste output.

Additionally, the contents of the database are:

mysql> select content from paste where paste_id = '567';
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| content                                                                                                                                                                                                                                                                                                                                                                                                       |
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| # An escaped linefeed
print "\n"

# An escaped escape and an n.
print "\\n"

# An escaped carriage return
print "\r"

# An escaped esacpe and an r.
print "\\r"

# escaped escape
print "\\"

# End of line that's escaped.
print "This string is waaaaaaay too large for me to possibly be able " \
      "to fit it in a single line"

# Some accidental backslashes: \\
# Four backslashes and an n: \\\\n | 
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

The database content suggests the issue is most likely in the mysql library escaping content coming from the database.

[scott]

The output from mysql suggest that mysql.awk is most likely not handling \\ correctly.

scott@megatron:~> echo "select content from paste where paste_id = '567'" | mysql -u<user> -p<password> awkbot 
content
# An escaped linefeed\nprint "\\n"\n\n# An escaped escape and an n.\nprint "\\\\n"\n\n# An escaped carriage return\nprint "\\r"\n\n# An escaped esacpe and an r.\nprint "\\\\r"\n\n# escaped escape\nprint "\\\\"\n\n# End of line that's escaped.\nprint "This string is waaaaaaay too large for me to possibly be able " \\\n      "to fit it in a single line"\n\n# Some accidental backslashes: \\\\\n# Four backslashes and an n: \\\\\\\\n

 the paste actually shows that precedence is being given to \n over \\.

[scott]

This is fixed in [91] and [92].