[ilyalesokhin-starkware]

refactor(circuit_common): bound seq_of_component_size by MAX_SEQUENCE_LOG_SIZE
This keeps the seq columns consistent with MAX_SEQUENCE_LOG_SIZE, which the
memory_id_to_big component relies on: it reserves ID_TO_BIG_MAX_ROWS ==
2^MAX_SEQUENCE_LOG_SIZE ids per instance and places consecutive instances at id
offsets that assume no instance exceeds that size. If MAX_SEQUENCE_LOG_SIZE is
inconsistent with the preprocessed columns, the id_to_big components can overlap.

Co-Authored-By: Claude Opus 4.8 (1M context) noreply@anthropic.com

[cursor]

PR Summary

Medium Risk
Changes STARK constraint construction for component height selection; misalignment with memory_id_to_big id spacing would be serious, but the change is intended to enforce that alignment.

Overview
seq_of_component_size now sums bit_k · seq_k only over log sizes 0..=MAX_SEQUENCE_LOG_SIZE, matching which seq_k columns the preprocessed trace defines, instead of using the per-proof max_component_size_bits() (trace log size + 1).

The loop still skips missing seq_{log_size} entries via preprocessed_columns.get, and get_n_instances_bit is called with the index converted from the u32 loop variable.

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This change is 

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Out-of-bounds instance bit index

High Severity

The loop now runs through MAX_SEQUENCE_LOG_SIZE, but when a matching seq_k column exists in preprocessed_columns for k at or above max_component_size_bits(), get_n_instances_bit indexes past the end of n_instances_bits (length log_trace_size + 1) and panics. The previous loop stopped at max_component_size_bits() and never hit those indices.

 

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