[RaphaelFakhri]

Fixes #191

All Submissions:

• Contributions should target the dev branch. Did you create your branch from dev?
• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

What this changes

Before this change, LegacyGenerator::make_point passed the point index straight to FBinReader::read_vector. When --num-vectors, --offset or --max-id goes past the number of vectors in the --fbin file, the upload panicked with an out-of-range slice index. The default --num-vectors is 100000, so any smaller file triggered the panic.

The legacy path now takes the index modulo the file's vector count. This matches what source: {type: file, strategy: from_start} already does for YAML uploads and for query generation.

Tests

generators::legacy::tests::fbin_vectors_wrap_past_the_end_of_the_file builds a two-vector fbin file and checks points 0, 1, 2 and 5. The test fails on dev with the out-of-range panic and passes with this change.