Editing Help:CS1 errors (section)

==<span id="wikilink_in_url">URL–wikilink conflict</span>==
<section begin="wikilink_in_url_help_text" />{{help desk}}{{#invoke:Cs1 documentation support|help_text_error_messages|err_wikilink_in_url}}

External links in a rendered citation are a combination of url-holding parameters, {{para|url}}, {{para|chapter-url}}, etc., with title-holding parameters, {{para|title}}, {{para|chapter}}, etc. Title-holding parameters may be [[wikilink]]ed to another Wikipedia article but not when there is a matching url-holding parameter in the citation. When this condition occurs, the wikilink is suppressed, the wiki markup ignored, and the rendered citation links to the external site.

With {{tlx|cite journal}}, auto-linking of the {{para|pmc}} or {{para|doi}} parameter value can cause this condition to occur implicitly without a specific url-holding parameter.

Some [[Help:Template|templates]] will also cause this error if they are part of a title-holding parameter. The error occurs when the template produces wikilinked content. For example, {{tlx|lang}} templates output a wikilinked category. Templates in title-holding parameters may also corrupt the citation's [[WP:COinS|COinS]] metadata. As a general rule, avoid using templates in title-holding parameters unless you know that the template's effects are entirely visual ({{tlx|!}} and the like).

This type of error may also occur in identifier-based templates ({{tlx|cite doi}}, etc.). When this happens, the error message is shown in the article but the error is actually located in the identifier-based citation template.

To resolve this error, remove wikilinks from title-holding parameters that are intended to be externally linked or remove the external URL, which will allow the internal wikilinks to work as expected. If the conflict is implicitly caused through auto-linking (see above), this can be disabled using {{para|title-link|none}}. If wikilink-producing templates are important to the citation, move them out of the CS1 template but leave them inside the citation's {{tag|ref}} tags. Some of the functionality provided by templates may also be available through CS1 parameters.

To resolve errors in identifier-based citation templates, the template must be edited to correct the error. Exercise caution when editing these templates because identifier-based citation templates are often used in multiple articles.

Pages with this error are automatically placed in {{#invoke:cs1 documentation support|help_text_cats|err_wikilink_in_url|pages=yes}}.<ref group="lower-alpha" name="categories" /><section end="wikilink_in_url_help_text" />