#133188 by Behrang, John Morahan, frega: Line break converter can result in empty node display due to PCRE limits

#638702 by jhodgdon: fix issues where the return value of db_affected_rows() was not properly considered

#566390 by Gábor Hojtsy, seutje, Jose Reyero: Apply locale import protection user setting to plural forms the same way we apply to other parts of the .po file

#265719 by kkaefer, JacobSingh, ksenzee, pivica: fix path mangling in CSS aggregation code to be sure to generate IE compatible CSS

#43462 by leafish_dylan, c960657, andypost: simplify and fix compatibility of compression code in page caching

#495956 by cafuego, sun, andypost, Josh Waihi, axyo: do not assume that the database will insert role numbers or filter format indexes in a specific way

#222926 by deviantintegral, sun, jcnventura, tic2000, jenlampton, smk-ka: htmlcorrector filter escapes HTML comments

#796048 by jbafford: if JS files are concatenated with a one line comment and a multiline comment, that can lead up to JS parse issues

#323438 by emok, chx, mfb: uploaded files become arrays in previews, so object property checking will not work on them (from PHP 5.2.12+)

#306611 by joshk, jbomb, sun, dereine, andypost: avoid calling nonexistent action callbacks (eg. when a module is disabled); also backport some documentation improvements

#523058 by catch, sun, c960657, smk-ka, pwolanin, andypost: optimize calls to check_plain() by trying to use new PHP 5 features and inlining UTF-8 checking

#587568 by Berdir, yhager: improve PHP 5.3 compatibility by using hook_nodeapi() the right way in node_search()

#229051 by jaydub, ainigma32, Josh Waihi, Dave Reid, druido, bellHead: solve top visitors pagination issues in statistics module with postgresql

#266488 by MadHarold, nbz, Damien Tournoud, sbandyopadhyay: fix some errors in username validation, clean up code style and add missing support for apostrophes

#362256 by pwolanin: backport poll module vote number form access handling from D7, avoid clearing vote numbers when editing a poll

#770598 by greggles, grendzy: move user login failure attempt logging to user_authenticate() to have unified logging with all kinds of authentication schemes, including blogapi

#462628 by Heine, pwolanin, dww: better documentation for taxonomy_form() to avoid possible security issues from contributed code

#320171 by Deve Reid, jbrauer: fix return value passing by reference in bootstrap.inc's IP address checking

#695468 by Caligan: document theme functions generating submission information for comments and nodes

#732064 follow up by pwolanin: move lock system loading earlier to avoid stepping over it or attempting to use it before it is loaded

#722190 by bjaspan: avoid infite recursion in filter_list_format() even if the database has broken data under Drupal

#261258 by Damien Tournoud, David_Rothstein, pwolanin: node_save() could result in broken data with certain database configurations when log messages are not included