_initialize_detector_backend put a bare "layout.xml" into the HDF5 plugin.
The IOC resolves that relative to its own working directory, where no such
file exists: the cSAXS SITORO IOC ships the layout as cfg/layout.xml
(installed at /ioc/X12SA-CPCL-FALCONX1/cfg/layout.xml), and that is what the
IOC configures at startup. BEC was overwriting a correct value with a broken
one on every device init.
The failure was silent and badly signposted. An unreadable layout does not
raise; the plugin simply refuses to open the output file later, reporting
"Error opening file ..., status=-1" with the actual cause buried in
XMLErrorMsg_RBV. Because a caget taken before a BEC device reload showed the
IOC's own valid value, the two readings disagreed and the layout looked
innocent.
The default is now cfg/layout.xml, overridable per deployment with an
xml_file_name key in deviceConfig ("" selects the plugin's built-in layout),
and on_connected reads XMLValid_RBV back and logs an error naming the file
and the IOC's message if the layout was rejected.
The existing on_connected test asserted the broken value; it now asserts the
default constant.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KLnmUurqcNd1FiDY5M2uZr
menzelandClaude Opus 5
d7ee8ef031