Category:CS1 errors: dates

This is a tracking category It is used to build and maintain lists of pages—primarily for the sake of the lists themselves. They are not part of the encyclopedia's categorization scheme. More information: This category is hidden on its member pages—unless the corresponding user preference is set. These categories are used to track, build and organize lists of pages needing "attention en masse" (for example, pages using deprecated syntax), or that may need to be edited at someone's earliest convenience. These categories also serve to aggregate members of several lists or sub-categories into a larger, more efficient list (discriminated by classifications).

Administrators: Please do not delete this category even if it is empty! This category may be empty occasionally or even most of the time.

This is a tracking category for CS1 citations with date-holding parameters where the date values do not comply with MOS:DATEFORMAT.

Help desk

Check date values in: |param1=, |param2=, ...

When CS1 citations contain date-holding parameters, an automated test is done to see if the dates are real dates that comply with a subset of WP:DATESNO.

To resolve this error, ensure that the date is an actual date and that the date format follows the Wikipedia style sheet in the named parameter. Some things to look for:

• misplaced, incorrect, or extraneous punctuation
• extraneous text
• incomplete year-initial dates
• hyphens instead of en dashes
• misspelling or improper capitalization
• date formats listed in WP:BADDATEFORMAT
• impossible dates (e.g., 29 February 2011)
• errors in |date= caused by errors in |year= or |month=
• more than one date in a date-holding parameter

WP:DATERANGE describes how to separate dates in a date range. Do not use  , –, or {{spaced ndash}} as these corrupt the metadata. To add an en dash, use the CharInsert edit tool or see Wikipedia:How to make dashes. A bot is often able to correct the separator, provided the overall format is unambiguous.

Future dates in CS1 citations are limited to current year + 1; that is, for 2015, citation dates in 2016 are acceptable but citation dates in 2017 and beyond are not.

Dates prior to 1582 are treated as Julian calendar dates. Dates from 1582 onward are treated as Gregorian calendar dates. The Julian calendar was used in some places until approximately 1923. Three Julian calendar dates in the overlap period, 29 February in the years 1700, 1800, and 1900, will cause this error message because those years are not leap years in the Gregorian calendar.

Pages with this error are automatically placed in Category:CS1 errors: dates.^[a]

While most of the Citation Style 1 error messages are visible to all readers, some remain hidden. Editors who wish to see all of the CS1 error messages can do so by updating their common or skin CSS stylesheet to include:

.citation-comment {display: inline !important;} /* show all Citation Style 1 error messages */

Even with this css installed, older pages in Wikipedia '​s cache may not have been updated to show these error messages even though the page is listed in one of the tracking categories. A WP:NULLEDIT will resolve that issue.

Notes[edit]