From: Sam Web <swebster@...>
Date: 2006-09-27T03:49:18+09:00
Subject: Fixnum/String randomly changing type

Hi,

I am seeing some odd behavior that look to me to like it could be a bug 
in Ruby.  Being new to the language, however, I wanted to see if there 
was another explanation.  I am using Ruby 1.8.4 on an Intel Mac.  The 
code at the bottom of this message is an excerpt from a class in a 
larger script.  It is using DBI to pull 10 fields from a MySQL database. 
The first 9 are integers (tinyint(4) in the database) and the last is a 
string (varchar(255) in the database).  When I run the below program as 
is, the puts outputs:

Info[0] class: String
Info[0] value: 0
Info[0] class: String
Info[0] value: 0
.
.
.

However, if I uncomment the 'info.each' line, I get:

Info[0] class: Fixnum
Info[0] value: 0
0
Info[0] class: Fixnum
Info[0] value: 0
0
.
.
.


So, it seams that just printing out the value in an 'each' loop causes 
it to change from a String to a Fixnum throughout the code segment.  The 
break statement makes no difference (it just reduces the output for the 
purpose of posting here).  It is my understanding that the MySQL driver 
for DBI should coerce the objects to numbers since that is their type in 
the database.  However, regardless of what type they start as, I don't 
understand how adding an each loop with a print in it can change the 
type.  Also, I can't seem to reproduce this behavior in a small test 
program.  I do know that the database queries are successful and are 
returning the proper values.  Does anyone have any ideas?  Is this a bug 
or is there some subtlety of type inferencing that I am missing?




@sthVulnID.fetch do |id|
      ids.push(id[0])
      begin
	    @sthVulnInfo.execute(id[0])
      rescue DBI::DatabaseError => e
	    puts "An error occurred getting vulnerability info"
	    puts "Variables: name:\"#{name}\"  k:\"#{k}\"  v:\"#{v}\""
	    puts "Error code: #{e.err}"
	    puts "Error message: #{e.errstr}"
	    exit
      end
      info = @sthVulnInfo.fetch_array


      puts "Info is: #{info[0].class}"
#     info.each { |newval| puts "#{newval.class}"; break }


      newVuln.addInfo('osvdb-location', 'physical') if ( info[0] == 1 )
      newVuln.addInfo('osvdb-location', 'local') if ( info[1] == 1 )
      newVuln.addInfo('osvdb-location', 'remote') if ( info[2] == 1 )
      newVuln.addInfo('osvdb-location', 'dialup') if ( info[3] == 1 )
      newVuln.addInfo('osvdb-location', 'unknown') if ( info[4] == 1 )
      newVuln.addInfo('osvdb-impact', 'confidentiality') if ( info[5] == 
1 )
      newVuln.addInfo('osvdb-impact', 'integrity') if ( info[6] == 1 )
      newVuln.addInfo('osvdb-impact', 'availability') if ( info[7] == 1 
)
      newVuln.addInfo('osvdb-impact', 'unknown') if ( info[8] == 1 )
      newVuln.addInfo('osvdb-title', info[9])
end

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