fix: skip missing sparse term lists

[jac0626]

Summary

Skip missing sparse-term posting lists in SparseTermDataCell::InsertHeapByTermLists.

The search path now ignores terms whose posting-list pointer is absent and clamps retained term size to the actual posting-list length before indexing. Regression coverage exercises both a null term list and an oversized recorded term size.

Fixes #1965.
Part of #1960.

Validation

• git diff --check
• Fork PR CI: https://github.com/jac0626/vsag/actions/runs/25477108783
• Log scan: target sparse_term_datacell.cpp runtime error is gone in this branch.

Known CI State

The fork PR CI run failed in Test X86 Functests on an unrelated HNSW recall assertion:

tests/test_index.cpp:535: REQUIRE( cur_recall > expected_recall * query_count * RECALL_THRESHOLD ), with nanf > 72.25f.

The same log still contains existing non-target runtime errors from fast_bitset.cpp and inner_index_interface.cpp, which are handled by separate PRs.

Notes

Local macOS rebuild was blocked by the existing CMake configuration error: gcc does not support using libc++.

[mergify]

Merge Protections

Your pull request matches the following merge protections and will not be merged until they are valid.

🟢 Require kind label

Wonderful, this rule succeeded.

• label~=^kind/

🟢 Require version label

Wonderful, this rule succeeded.

• label~=^version/

🟢 Require linked issue for feature/bug PRs

Wonderful, this rule succeeded.

• body~=(?im)(?:^|[\s\-\*])(?:close[sd]?|fix(?:e[sd])?|resolve[sd]?)\s*:?\s+(?:#\d+|[\w.\-]+/[\w.\-]+#\d+|https?://github\.com/[\w.\-]+/[\w.\-]+/issues/\d+)

[gemini-code-assist]

Code Review

This pull request improves the safety of SparseTermDataCell::InsertHeapByTermLists by adding bounds checks, null pointer validation, and clamping term sizes to prevent out-of-bounds access. It also includes unit tests for these scenarios. The review feedback suggests simplifying the new conditional check by removing a redundant size comparison to improve readability.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Skip missing sparse-term posting lists during search by guarding against null posting-list pointers and clamping the effective term size to the actual posting-list length to avoid out-of-bounds indexing.

Changes:

• Add safety checks in SparseTermDataCell::InsertHeapByTermLists for missing/empty term lists and clamp retained term_size to the posting-list length.
• Add regression tests covering (1) null term list skip and (2) oversized recorded term size clamping.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
src/datacell/sparse_term_datacell.cpp	Skips missing sparse-term lists and clamps retained term size to posting-list length before indexing.
src/datacell/sparse_term_datacell_test.cpp	Adds unit coverage for null posting-list pointers and oversized recorded term sizes.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.