fix: simple fix a rust compile warning

[yihong0618]

this patch simple fix a rust compile warning when run ./build.sh rust

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📝 Walkthrough

Summary by CodeRabbit

• Tests
  • Minor test code refinement in the search functionality test suite.

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Note: This release contains internal test improvements with no user-facing changes.

Walkthrough

The PR removes unnecessary mutability from the neighbors_host variable in the test_cagra_search_with_filter test function. The variable is not mutated after initialization, so the mut keyword is redundant.

Changes

Test mutability cleanup in CAGRA search filter test

Layer / File(s)	Summary
Remove unnecessary mutability from test variable rust/cuvs/src/cagra/index.rs	The neighbors_host ndarray binding in test_cagra_search_with_filter is changed from mutable to immutable, eliminating an unused mut annotation.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change as fixing a Rust compile warning, which aligns with the changeset that removes an unused mut binding.
Description check	✅ Passed	The description explicitly states the intent to fix a Rust compile warning when running ./build.sh rust, which is directly related to the changeset.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

rust/cuvs/src/cagra/index.rs (1)

303-314: ⚠️ Potential issue | 🔴 Critical | ⚡ Quick win

Make neighbors_host mutable for the to_host(&mut ...) call

neighbors_host is declared as immutable (let neighbors_host = ...) but is later passed as &mut neighbors_host to neighbors.to_host(...), which will fail to compile.

Suggested fix

-        let neighbors_host = ndarray::Array::<u32, _>::zeros((n_queries, k));
+        let mut neighbors_host = ndarray::Array::<u32, _>::zeros((n_queries, k));

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@rust/cuvs/src/cagra/index.rs` around lines 303 - 314, neighbors_host is
declared immutable but later passed as &mut to neighbors.to_host(&res, &mut
neighbors_host); make neighbors_host mutable by changing its binding to be
mutable (e.g., let mut neighbors_host = ...) so the &mut borrow is valid; update
the declaration of neighbors_host (and similarly distances_host if needed) where
ManagedTensor::from(&neighbors_host) is created and used with neighbors.to_host
and distances.to_host to ensure correct mutability.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Outside diff comments:
In `@rust/cuvs/src/cagra/index.rs`:
- Around line 303-314: neighbors_host is declared immutable but later passed as
&mut to neighbors.to_host(&res, &mut neighbors_host); make neighbors_host
mutable by changing its binding to be mutable (e.g., let mut neighbors_host =
...) so the &mut borrow is valid; update the declaration of neighbors_host (and
similarly distances_host if needed) where ManagedTensor::from(&neighbors_host)
is created and used with neighbors.to_host and distances.to_host to ensure
correct mutability.

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ℹ️ Review info

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Run ID: 67b8035a-282b-49ec-a353-1368f1862a0b

📥 Commits

Reviewing files that changed from the base of the PR and between caf24ce and 3352e38.

📒 Files selected for processing (1)

• rust/cuvs/src/cagra/index.rs