Èd:CS1 errors

This page describes the error messages reported by the Modèl:Cs1 and Modèl:Cs2 citations, what they mean, and how editors might resolve the errors.

Prior to 2013, the CS1|2 templates used the meta-template {{citation/core}}. In 2013, as part of the WP:LUA project, Wikipedia editors upgraded the CS1|2 series of templates to use a single Lua module. Module:Citation/CS1 is the engine that controls how CS1|2 citations are displayed and how citation data are passed to external referencing tools through COinS metadata. The benefits of the upgrade are enhanced performance, reduced complexity and redundancy, and for the purposes of this page, improved error detection, categorization, and reporting.

Controlling error message display

While most of the Modèl:Cs1 and Modèl:Cs2 error messages are visible to all readers, some remain hidden. Editors who wish to see all of the CS1|2 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.

The above code is required if you wish see maintenance category messages:

Category:CS1 maintenance (link)

Editors who do not wish to see any of the CS1 error messages can hide them all by updating their common or skin CSS stylesheet to include:

​.citation-comment {display: none;} /* hide all Citation Style 1 error messages */ ​

|access-date= requires |url=

Modèl:Help desk (error message hidden by default)

The |access-date= (or its alias, |accessdate=) is the date that the online resource addressed by |url= was added to the article. If |access-date= has been included in the citation without |url= then this message appears. If the citation does not use a web link, then |access-date= is redundant and should be removed.

When the online resource has a publication or other fixed date associated with it, |access-date= is of limited value though may be useful in identifying an appropriate archived version of the resource. Without |url=, |access-date= is not considered useful.

To resolve this error, provide a value for |url= or remove |access-date=. Editors should try to determine why the citation has |access-date= without |url=. For example, the citation may never have had a |url=, or |url= may have been removed because it links to a site that violates the creator's copyright (see WP:COPYLINK), or because |url= was deemed to be dead and (mistakenly) removed. If the citation never had |url= or it was removed for copyright violations, remove |access-date=. When a dead |url= has been removed, restore the |url= and if possible repair it (see WP:LINKROT).

Pages with this error are automatically placed in Category:Pages using citations with accessdate and no URL.

|archive-url= requires |archive-date=

|archive-date= (or its alias, |archivedate=), identifies the date that the web resource was archived.

To resolve this error, provide a value for |archive-date=. For web resources archived at archive.org, the archival date can be found in the |archive-url=; for resources archived at webcitation.org, the cache date is included in the archive header.

Pages with this error are automatically placed in Category:Pages with archiveurl citation errors.

|archive-url= requires |url=

A properly formatted citation that includes |archive-url= and |archive-date= requires |url=. When the citation includes |dead-url=no, the ordering of elements in the rendered citation is changed to put the original url first.

To resolve this error, provide a value for |url=. For web resources archived at archive.org, the original url can be found in the |archive-url= value; for resources archived at webcitation.org, the original url is included in the archive header.

Pages with this error are automatically placed in Category:Pages with archiveurl citation errors.

|arxiv= required

{{cite arxiv}} requires one, but not both, of the identifier parameters |arxiv= or |eprint=.

To resolve this error, ensure that the template has |arxiv= or |eprint= with a properly constructed value.

Pages with this error are automatically placed in Category:CS1 errors: arXiv.

|chapter= ignored

Modèl:Cs1 templates {{cite web}}, {{cite news}}, {{cite journal}}, {{cite press release}}, {{cite podcast}}, {{cite newsgroup}}, and template {{citation}} when Modèl:Tld uses |work= or any of its aliases, do not support |chapter= or the aliases |contribution=, |entry=, |article=, or |section=.

To resolve this error, use a more appropriate citation template or place the content of the |chapter= parameter in |title=.

Pages with this error are automatically placed in Category:CS1 errors: chapter ignored.

Check |arxiv= value

When Modèl:Cs1 and Modèl:Cs2 templates contain |arxiv=, a test is done to see if the arXiv identifier conforms with the arXiv identifier scheme. The identifier is checked for a valid number of digits in the article id; valid year and month values; and properly-placed hyphens, slashes, and dots.

To resolve this error, ensure that the |arxiv= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: arXiv.

Check |asin= value

When Modèl:Cs1 and Modèl:Cs2 templates contain |asin=, a test is done to see if the ASIN identifier is contains ten upper-case alphanumeric characters without punctuation or spaces and that if the first character is numeric, that the ASIN conforms to the rules for a ten-digit ISBN.

To resolve this error, ensure that the |asin= value is correct.

If the |asin= value is correct and all-numeric, use |isbn= instead and delete any |asin-tld= parameters. Articles with CS1 citations that use |asin= with all numeric values are categorized in Modèl:Cl.

Pages with this error are automatically placed in Category:CS1 errors: ASIN.

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

When Modèl:Cs1 and Modèl:Cs2 templates contain date-holding parameters, an automated test is done to see if the dates are real dates that comply with a subset of Wikipedia's Manual of Style, specifically MOS:BADDATEFORMAT.

To resolve this error, ensure that the date is an actual date and that the date format follows the Wikipedia Manual of Style 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 (see MOS:ALLCAPS for more detail that is not in the above-linked Dates section)
• date formats listed in MOS: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

The MOS section on date ranges 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 |date= in CS1|2 citations are limited to current year + 1; that is, for 2024, citation dates in 2025 are acceptable but citation dates in 2026 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.

The access date (in |access-date=) is checked to ensure that it is between 15 January 2001 (the founding date of Wikipedia) and today's date plus one day (currently 17 avril 2024 UTC), because it represents the date that an editor viewed a web-based source to verify a statement on Wikipedia. Because editors may be in time zones that are one day ahead of the UTC date, one extra day is accepted.

Pages with this error are automatically placed in Category:CS1 errors: dates.

Examples of unacceptable dates and how to fix them

Issue	Unacceptable	Acceptable
Hyphen (use dash)	|date=2002-2003	|date=2002–2003
Slash (use dash)	|date=2002/2003	|date=2002–2003
Month capitalization	|date=28 february 1900	|date=28 February 1900
Month capitalization	|date=28 FEBRUARY 1900	|date=28 February 1900
Season capitalization	|date=spring 2011	|date=Spring 2011
Future date (typo)	|date=2102	|date=2012
Access date impossibly far in the past (typo)	|access-date=1 January 2001	|access-date=1 January 2010
Ambiguous date range or year and month	|date=2002-03	Modèl:Plainlist
Bad abbreviation	|date=Febr. 28, 1900	Modèl:Plainlist
Nonexistent date	|date=February 29, 1900
Comma in month and year	|date=February, 1900	|date=February 1900
Non-date text	|date=2008, originally 2000	|date=2008 |orig-year=2000
Zero-padding	|date=January 04, 1987	|date=January 4, 1987
Date with slashes	|date=12/6/87	Modèl:Plainlist
Two-digit year	|date=87-12-06	|date=1987-12-06
One-digit month or day	|date=2007-3-6	|date=2007-03-06
Wikified date	|date=[[April 1]], [[1999]]	|date=April 1, 1999
"mm-dd-yyyy" or "dd-mm-yyyy" date format	|date=07-12-2009	|date=7 December 2009 or |date=July 12, 2009 or |date=December 7, 2009
Approximate or uncertain dates	|date=circa 1970 or |date={{circa}} 1970	|date=c. 1970

Check |doi= value

When Modèl:Cs1 and Modèl:Cs2 templates contain |doi=, a test is done to see if the prefix portion of the DOI value contains the proper 10. registry identifier. Additionally, the |doi= value is checked to make sure that it does not contain spaces or en dashes and does not end with punctuation. Further validation of the DOI is not performed.

To resolve this error, ensure that the |doi= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: DOI.

Check |hdl= value

When Modèl:Cs1 and Modèl:Cs2 templates contain |hdl=, a test is done to see if the hdl value looks like a properly defined value. The |hdl= value is checked to make sure that it does not contain spaces or en dashes and does not end with punctuation. Further validation of the hdl is not performed.

To resolve this error, ensure that the |hdl= value is correct.

Pages with this error are automatically placed in Category:CS1 errors: HDL.

Check |isbn= value

Modèl:Cs1 and Modèl:Cs2 templates that contain |isbn= are checked to ensure that the ISBN is the proper length (ten or thirteen digits), that the ISBN uses the correct optional separators (simple space or hyphen), and that the final check digit is correct according to the ISBN specification. Only one ISBN is allowed in this field because the whole |isbn= value is included in the citation's COinS metadata. See also Wikipedia:COinS. More than one ISBN, or characters that are not part of the ISBN, corrupt the COinS metadata and may also corrupt the link to Special:BookSources.

To resolve this error, ensure that the |isbn= value is correct, that only one ISBN is used, that the proper optional separators are used, and that no other text is included. Use the 13-digit ISBN when it is available. When a 10-digit ISBN is used, if the check digit is a lowercase 'x', change it to an uppercase 'X'.

• Do not try to resolve the error by simply recalculating the check digit. The check digit is there to check whether the main part of the number is correct. If the ISBN is failing to validate, it is likely that there is a typo in the main part of the number. In this case, recalculating the check digit results in an apparently valid ISBN that leads to the wrong source (or to nowhere).
• If you only have a 10-digit ISBN, do use the number as-is, do not try to convert it to the 13-digit form.
• If the ISBN as printed in your source is refusing to validate, do check both the front matter and the book cover for ISBNs. It is not uncommon for the ISBN to be misprinted in the front matter but correct on the cover.
• Do preview your edit and check that the new ISBN does now link to the correct source.

In very rare cases, publishers have released books with malformed ISBNs. If you are certain that a non-conforming ISBN truly corresponds to the published work, then you can add |ignore-isbn-error=true to the citation in order to suppress the error message. In many cases, books may have been reissued with a corrected ISBN. Use a corrected ISBN when possible.

See also Wikipedia:ISBN.

Pages with this error are automatically placed in Category:Pages with ISBN errors.

Check |ismn= value

Modèl:Cs1 and Modèl:Cs2 templates that contain |ismn= are checked to ensure that the ISMN is the proper length (thirteen digits), that the ISMN uses the correct optional separators (simple space or hyphen), and that the final check digit is correct according to the ISMN specification. Only one ISMN is allowed in this field because the whole |ismn= value is included in the citation's COinS metadata. See also Wikipedia:COinS. More than one ISMN, or characters that are not part of the ISMN, corrupt the COinS metadata.

To resolve this error, ensure that the |ismn= value is correct, that only one ISMN is used, that the proper optional separators are used, and that no other text is included. Make sure that the ISMN contains exactly 13 digits.

Pages with this error are automatically placed in Category:CS1 errors: ISMN.