Edit report at https://bugs.php.net/bug.php?id=34906&edit=1
ID: 34906
Updated by: u...@php.net
Reported by: feldgendler at mail dot ru
Summary: mysql: no way to get errno for a failed secondary
connection attempt
-Status: Assigned
+Status: Wont fix
Type: Feature/Change Request
Package: MySQL related
Operating System: *
PHP Version: 5CVS-2005-10-19 (cvs)
Assigned To: mysql
Block user comment: N
Private report: N
New Comment:
It may be a valid feature request but meanwhile ext/mysql is in the process of
being softly deprecated. So, no feature additions for ext/mysql any more.
Security fixes, sure, feature additions, sorry, migrate to ext/mysqli.
Previous Comments:
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[2011-02-16 12:07:29] johan...@php.net
The "easy" solution is to use mysqli without this default connection magic.
Making this work doesn't look trivial as these two cases have to work:
mysql_connect('localhost', 'valid', 'password');
mysql_connect('localhost', 'invalid', 'something');
mysql_query('invalid query');
echo mysql_error(); // should report the query error
as well as
mysql_connect('localhost', 'valid', 'password');
mysql_query('invalid query');
mysql_connect('localhost', 'invalid', 'something');
echo mysql_error(); // Should report the connect error
Assigning to mysql team
------------------------------------------------------------------------
[2011-02-16 11:43:05] tony2...@php.net
Reassigned to Johannes.
The patch is still available here: http://dev.daylessday.org/diff/bug34906.diff
------------------------------------------------------------------------
[2005-10-18 13:51:40] feldgendler at mail dot ru
About the patch: I think it's not enough. Once a connection attempt has failed,
conect_errno will be nonzero, and mysql_errno() without arguments always will
return this value. This will be too much deviation from the current behavior --
in fact, many always call mysql_errno() without arguments. Here is a typical
script which will be broken:
if (!mysql_connect('dbhost', 'user', 'pass')) {
mysql_connect('backup-dbhost', 'user', 'pass');
}
// ...
if (!mysql_query("...")) {
echo mysql_errno(); // This will print connect_errno!
}
I think that connect_errno should be reset to zero somewhere, but I don't know
where it would be appropriate. mysql_errno() shouldn't reset connect_errno
because mysql_error() and mysql_errno() are expected to be idempotent.
------------------------------------------------------------------------
[2005-10-18 13:43:11] tony2...@php.net
Assigned to the maintainer.
Georg, please check the patch:
http://tony2001.phpclub.net/dev/tmp/bug34906.diff
------------------------------------------------------------------------
[2005-10-18 13:19:52] feldgendler at mail dot ru
Description:
------------
This is actually a bug in the well-defined and documented API, so there is no
reproduce code here.
After successfully establishing a connection, when an attempt to create another
connection fails, there is no way to find out the errno. This is because
mysql_errno() always uses an established link, either the one passed as the
argument or the default one. There is just no way to find out why the second
connection failed.
// assume this one succeeds
$first_connection = mysql_connect($host1, $u1, $p1);
// at this point, $first_connection is the default link
// assume this one fails
$second_connection = mysql_connect($host2, $u2, $p2);
// $second_connection is false,
// $first_connection is still the default link
echo mysql_errno();
// 0 is printed because there is no error
// on $first_connection
Before stamping "Bogus" on this bug, please note the following:
1. I have read the manual about mysql_errno() and mysql_connect(). Every word
of it. Even more, I think that PHP currently behaves as documented. But it's
just wrong because there is no way to find out why a connection has failed.
2. I have read other bug reports about mysql_errno(). They are actually about
other issues, or they don't state this problem clearly enough, so I'm filing
this bug report to make it clear what the problem is.
3. I have read the source code of the mysql extension. From the source, I've
found out that the error code and message from a failed connection attempt is
really stored in mysql_globals (connect_errno and connect_error), but
mysql_errno() PHP function only returns MySG(connect_errno) when the function
is invoked without arguments AND there is no default link. If there is a
default link, and an attempt to establish a second one has failed, there isn't
a way to have MySG(connect_errno) returned to the PHP program.
It is not obvious how to fix this bug, because it isn't a deviation from the
documented behavior, but rather an incompleteness of the API. Two of the
possible approaches are proposed here:
http://www.mail-archive.com/internals@lists.php.net/msg02524.html
------------------------------------------------------------------------
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