[esauro]

libhegel 0.46 changed every string parameter and output of the C ABI to hegel_string_t (a {data, len} struct, by value for required strings, by nullable pointer where absent is meaningful, as a contiguous array for name lists), and renamed hegel_generate_string_result_free to hegel_owned_string_free. Both bindings marshal strings that way now:

• RealLibhegel (FFM): a STRING_LAYOUT struct layout in the descriptors, str/strPtr/strArray helpers for inputs, readString/readStringPtr for outputs; hegel_context_last_error returns the struct by value, so its downcall takes an arena as allocator.
• JnaLibhegel (JNA): a HegelString Structure (with ByValue) replaces the String parameters and the BufferResult struct; strArray writes the struct array and the string bytes into one Memory block so nothing inside it can be collected during the call.

A null Java string crosses as {NULL, 0} by value, which the engine reads as an empty string, so a null regex pattern is now the empty pattern rather than E_INVALID_ARG; the edge tests say so, and new round-trip tests send a label, an origin, a database path and name lists through the engine and read the origin back.

One behaviour change reaches the shared suite: since 0.45.2 a run that never generates a valid case ends in the engine's Unsatisfiable error even with the filter-too-much health check suppressed, instead of passing vacuously.