Affects Version/s: 2.8.8
Fix Version/s: None
Component/s: Module: Taskchain
While attempting to reduce the list of students in a chain grades table, using the letters of one of the First Name or Surname filters, a dml_exception exception is thrown with the mixedtypesqlparam value.
Please see below the error message:
This issue seems to come from an incompatibility between the use of question mark placeholders in the mod_taskchain_report_chaingrades_renderer::select_sql_record() method and named placeholders provided by moodle's tablelib flexible_table::get_sql_where().
The latters are merged into the chain grade generated sql query.
The rendering process is stopped in moodle_database::fix_sql_params() which does not allow the use of two different placeholder types.
No problem noticed when using the numbering pagination.
Step to reproduce in a course containing students and a working taskchain instance:
1. in the Navigation Block, under the taskchain link, click on Class reports > Chain grades
2. click on a letter of either the First Name or the Surname filter.
What you currently get is the exception message above, while we expect to see the report table filtered.