Fixing Fatal Process Aborts in TensorFlow Lookup Tables

Описание и применение

Исправление необратимых сбоев при экспорте таблиц поиска TensorFlow путем проверки сигнатур перед выделением памяти.

Calling TensorFlow lookup table export operations with mismatched data types causes an immediate SIGABRT crash, preventing graceful error handling.

Implemented signature validation in LookupTableExportOp, preventing hard crashes and enabling proper error propagation.

1. Define a StaticHashTable with int64 keys and values.
2. Attempt to export the table using tf.raw_ops.LookupTableExportV2 with Tkeys/Tvalues set to tf.string.
3. Observe the process abort due to a CHECK_EQ failure.
4. Apply the patch adding MatchSignature to LookupTableExportOp.
5. Re-run the export; now an InvalidArgumentError is raised.
6. Add a unit test to ensure signature mismatches are caught.

LookupTableExportOp never verified signatures. It immediately called table->ExportValues(ctx).

The fix was straightforward and matches the pattern established across all other lookup table kernels in lookup_table_op.cc.