Trailing slash on RSS feed URL generates a spurious blank line in XML output

[Frobenius]

When generating RSS feeds and using permalinks, the url to the RSS feed includes a trailing slash. When the url contains a trailing slash, row 1 of the RSS XML generated by WordPress contains a blank line. This causes the RSS feed to fail validation. Here is an example:

​http://www.valenceband.com/wp/feed/ ...generates a blank line on row 1.
​http://www.valenceband.com/wp/feed ...does not generate a blank line.

The url without permalinks works perfectly, of course:

​http://www.valenceband.com/wp/?feed=rss2

I have only tested this with 1.5.1.3.

Why does the trailing slash generate a blank line in the RSS feed XML? It works the same with any theme and with plug-ins deactivated. Perhaps the get_feed_link function in template-functions-links.php could be modified to generate a url without the trailing slash when using permalinks.

[markjaquith]

Cannot duplicate. Could you paste your relevant mod_rewrite lines please? (from .htaccess ... include all the wp/feed related ones)

[Frobenius]

Every module has been upgraded to WordPress 1.5.2 and now it no longer matters if there is a trailing slash or not, a blank line is generated (with default theme and all plugins disabled), so the problem has grown worse, not better. I haven't any idea which .htaccess lines are relevant. Here is the .htaccess file generated by WordPress:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /wp/
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^{.*$ - [S=45]
RewriteRule} (sulfur_island)/trackback/?$ /wp/index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule ^{(sulfur_island)/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule} (sulfur_island)/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^{(sulfur_island)/page/?([0-9]{1,})/?$ /wp/index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule} (sulfur_island)(/[0-9]+)?/?$ /wp/index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule ^{(mof)/trackback/?$ /wp/index.php?pagename=$1&tb=1 [QSA,L]
RewriteRule} (mof)/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule ^{(mof)/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?pagename=$1&feed=$2 [QSA,L]
RewriteRule} (mof)/page/?([0-9]{1,})/?$ /wp/index.php?pagename=$1&paged=$2 [QSA,L]
RewriteRule ^{(mof)(/[0-9]+)?/?$ /wp/index.php?pagename=$1&page=$2 [QSA,L]
RewriteRule} feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?&feed=$1 [QSA,L]
RewriteRule ^{(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?&feed=$1 [QSA,L]
RewriteRule} page/?([0-9]{1,})/?$ /wp/index.php?&paged=$1 [QSA,L]
RewriteRule ^{comments/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?&feed=$1&withcomments=1 [QSA,L]
RewriteRule} comments/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?&feed=$1&withcomments=1 [QSA,L]
RewriteRule ^{comments/page/?([0-9]{1,})/?$ /wp/index.php?&paged=$1 [QSA,L]
RewriteRule} search/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?s=$1&feed=$2 [QSA,L]
RewriteRule ^{search/(.+)/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?s=$1&feed=$2 [QSA,L]
RewriteRule} search/(.+)/page/?([0-9]{1,})/?$ /wp/index.php?s=$1&paged=$2 [QSA,L]
RewriteRule ^{search/(.+)/?$ /wp/index.php?s=$1 [QSA,L]
RewriteRule} rsp/category/(.+)/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?category_name=$1&feed=$2 [QSA,L]
RewriteRule ^{rsp/category/(.+)/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?category_name=$1&feed=$2 [QSA,L]
RewriteRule} rsp/category/(.+)/page/?([0-9]{1,})/?$ /wp/index.php?category_name=$1&paged=$2 [QSA,L]
RewriteRule ^{rsp/category/(.+)/?$ /wp/index.php?category_name=$1 [QSA,L]
RewriteRule} rsp/author/([^{/]+)/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?author_name=$1&feed=$2 [QSA,L]
RewriteRule} rsp/author/([^{/]+)/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?author_name=$1&feed=$2 [QSA,L]
RewriteRule} rsp/author/([^{/]+)/page/?([0-9]{1,})/?$ /wp/index.php?author_name=$1&paged=$2 [QSA,L]
RewriteRule} rsp/author/([^{/]+)/?$ /wp/index.php?author_name=$1 [QSA,L]
RewriteRule} rsp/date/([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?year=$1&monthnum=$2&day=$3&feed=$4 [QSA,L]
RewriteRule ^{rsp/date/([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?year=$1&monthnum=$2&day=$3&feed=$4 [QSA,L]
RewriteRule} rsp/date/([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/page/?([0-9]{1,})/?$ /wp/index.php?year=$1&monthnum=$2&day=$3&paged=$4 [QSA,L]
RewriteRule ^{rsp/date/([0-9]{4})/([0-9]{1,2})/([0-9]{1,2})/?$ /wp/index.php?year=$1&monthnum=$2&day=$3 [QSA,L]
RewriteRule} rsp/date/([0-9]{4})/([0-9]{1,2})/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?year=$1&monthnum=$2&feed=$3 [QSA,L]
RewriteRule ^{rsp/date/([0-9]{4})/([0-9]{1,2})/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?year=$1&monthnum=$2&feed=$3 [QSA,L]
RewriteRule} rsp/date/([0-9]{4})/([0-9]{1,2})/page/?([0-9]{1,})/?$ /wp/index.php?year=$1&monthnum=$2&paged=$3 [QSA,L]
RewriteRule ^{rsp/date/([0-9]{4})/([0-9]{1,2})/?$ /wp/index.php?year=$1&monthnum=$2 [QSA,L]
RewriteRule} rsp/date/([0-9]{4})/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?year=$1&feed=$2 [QSA,L]
RewriteRule ^{rsp/date/([0-9]{4})/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?year=$1&feed=$2 [QSA,L]
RewriteRule} rsp/date/([0-9]{4})/page/?([0-9]{1,})/?$ /wp/index.php?year=$1&paged=$2 [QSA,L]
RewriteRule ^{rsp/date/([0-9]{4})/?$ /wp/index.php?year=$1 [QSA,L]
RewriteRule} rsp/([0-9]+)/trackback/?$ /wp/index.php?p=$1&tb=1 [QSA,L]
RewriteRule ^{rsp/([0-9]+)/feed/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?p=$1&feed=$2 [QSA,L]
RewriteRule} rsp/([0-9]+)/(feed|rdf|rss|rss2|atom)/?$ /wp/index.php?p=$1&feed=$2 [QSA,L]
RewriteRule ^{rsp/([0-9]+)/page/?([0-9]{1,})/?$ /wp/index.php?p=$1&paged=$2 [QSA,L]
RewriteRule} rsp/([0-9]+)(/[0-9]+)?/?$ /wp/index.php?p=$1&page=$2 [QSA,L]

Permalinks work on the site. I suspect it is something with the .htaccess as well, but I am not an expert by any means. If it isn't anything obvious, please resolve as invalid since it may be ISP or web server specific and nothing to do with WordPress.

[Frobenius]

Fixed by upgrading to WordPress 2.0