A failure may occur when using the s9api Serializer class in conjunction with an XSLT stylesheet that users character maps. The error message is:
Cannot use character maps in an environment with no Controller
The failure occurs only if the <xsl:output> declaration, as well as specifying use-character-maps, also specifies an explicit method. (If the method is defaulted, then decisions on serialization are made later, by which time a Controller is available).
A patch is being placed in Subversion for the 9.1 branch, and a JUnit test case has been added.