6. A computer-readable storage device containing a program which, when executed, performs an operation for detecting configuration conflicts between configuration files in a content management system (CMS), the operation comprising: storing a configuration set associated with one or more documents managed by the CMS, wherein each document of the one or more documents has a corresponding document type; receiving a content processing rule to be applied to one or more documents, wherein the content processing rule defines an operation to be performed by the CMS whenever a document of a document type specified by the content processing rule is checked-in to or checked-out from the CMS, and wherein the operation to be performed by the CMS includes, at least in part, modifying at least one document attribute in the one or more documents; determining that the at least one document attribute referenced by the content processing rule is a member of a repeating attribute group specified by a document type configuration associated with the document type specified in the content processing rule, wherein the repeating attribute group specifies a plurality of document attributes that should occur with the same number of values in instances of the document type; upon determining that, when applied to a first instance of the document type, the content processing rule could modify the first instance of the document type to include a differing number of values for the plurality of document attributes specified in the repeating attribute group, notifying a system administrator; generating an external schema validation rule configured to ensure that a number of occurrences of the plurality of document attributes in the first instance of the document type matches the number of occurrences of the plurality of document attributes in the modified first instance of the document type; and accepting the received content processing rule, whereby the operation defined by the content processing rule will be performed by the CMS whenever documents of the document type associated with the content processing rule are checked-in to or checked-out of the CMS.
10. The computer-readable storage device of claim 6 , wherein the external schema validation rule is an XML schema constraint.