VirtualStorageProvider: Make new() private, add new_physical

[Copilot]

Completed Changes

• Made VirtualStorageProvider::new() fully private (not just doc-hidden)
• Updated all unit tests in virtual_storage_provider.rs to use new_memory()
• Updated all usages across diskann-providers, diskann-disk, and diskann-tools to use specific constructors
• Added VirtualStorageProvider::new_physical to clippy.toml disallowed-methods list
• Removed all unused imports (MemoryFS, OverlayFS)
• Made test helper functions generic over filesystem type where needed
• Fixed doc tests:
  • Added missing use std::io::Write; import to doc examples
  • Removed doc examples that write to physical filesystem (new_physical and new_overlay)
  • Simplified to only show new_memory() usage
  • Removed unnecessary turbofish notation in test code
• Verified all checks pass:
  • ✅ cargo fmt --all --check
  • ✅ cargo clippy --locked --workspace --all-targets --no-deps
  • ✅ cargo test --doc --workspace
  • ✅ All unit tests pass

All PR review feedback has been addressed.

Original prompt

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This section details on the original issue you should resolve

<issue_title>VirtualStorageProvider: encourage use of new_overlay or new_memory</issue_title>
<issue_description>Make VirtualStorageProvider::new private.
Also add VirtualStorageProvider::new_physical<P: AsRefstd::path::Path>(path: P).
Expose only new_overlay(), new_memory(), new_physical().

Examples like these should be replaced with VirtualStorageProvider::new_memory():
let fs = OverlayFS::new(&[MemoryFS::default().into()]);
let storage_provider = VirtualStorageProvider::new(fs);

Original post:

Do you see any value in making VirtualStorageProvider::new much harder to call to encourage use of new_overlay or new_memory? Maybe with like a new_physical and then linting that with clippy?

Originally posted by @hildebrandmw in #700</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes VirtualStorageProvider: encourage use of new_overlay or new_memory #703

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 96.00000% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.99%. Comparing base (87a0757) to head (c3daeb3).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...-providers/src/storage/virtual_storage_provider.rs	50.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #764      +/-   ##
==========================================
+ Coverage   88.98%   88.99%   +0.01%     
==========================================
  Files         428      428              
  Lines       78365    78420      +55     
==========================================
+ Hits        69730    69788      +58     
+ Misses       8635     8632       -3     

Flag	Coverage Δ
miri	88.99% <96.00%> (+0.01%)	⬆️
unittests	88.99% <96.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
diskann-disk/src/build/builder/build.rs	94.16% <100.00%> (-0.03%)	⬇️
diskann-disk/src/storage/cached_reader.rs	99.16% <100.00%> (-0.02%)	⬇️
diskann-disk/src/storage/quant/generator.rs	92.72% <100.00%> (+0.02%)	⬆️
diskann-disk/src/storage/quant/pq/pq_generation.rs	93.33% <100.00%> (ø)
...ovider/async_/fast_memory_quant_vector_provider.rs	98.50% <100.00%> (ø)
...aph/provider/async_/fast_memory_vector_provider.rs	95.12% <100.00%> (ø)
...rs/src/model/graph/provider/async_/inmem/scalar.rs	96.02% <100.00%> (ø)
...ph/provider/async_/memory_quant_vector_provider.rs	98.38% <100.00%> (ø)
...el/graph/provider/async_/memory_vector_provider.rs	98.30% <100.00%> (ø)
.../graph/provider/async_/simple_neighbor_provider.rs	92.16% <100.00%> (ø)
... and 12 more

... and 2 files with indirect coverage changes

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[Copilot]

Pull request overview

This PR tightens the diskann_providers::storage::VirtualStorageProvider API by making the generic new() constructor private and pushing callers toward explicit constructors (new_memory, new_overlay, new_physical) that better communicate intent and reduce accidental real-filesystem usage in tests.

Changes:

• Made VirtualStorageProvider::new() fully private and updated call sites to use intent-specific constructors.
• Added VirtualStorageProvider::new_physical(...) for sandboxed physical filesystem usage.
• Added a Clippy disallowed-methods rule to discourage new_physical() in tests and updated examples/bench code accordingly.

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
diskann-tools/src/utils/relative_contrast.rs	Switched tests from VirtualStorageProvider::new(MemoryFS) to new_memory().
diskann-tools/src/utils/build_disk_index.rs	Switched tests to VirtualStorageProvider::new_memory().
diskann-providers/src/utils/storage_utils.rs	Updated tests to use new_memory() instead of constructing MemoryFS directly.
diskann-providers/src/utils/sampling.rs	Updated tests to use new_memory().
diskann-providers/src/utils/medoid.rs	Updated tests to use new_memory() and write via storage_provider.filesystem().
diskann-providers/src/utils/file_util.rs	Updated tests to use new_memory().
diskann-providers/src/storage/virtual_storage_provider.rs	Made new() private, added new_physical(), updated doctest examples and unit tests.
diskann-providers/src/storage/sq_storage.rs	Updated tests to use new_memory().
diskann-providers/src/storage/protos/storage.rs	Updated tests to use new_memory().
diskann-providers/src/storage/pq_storage.rs	Updated tests to use new_memory().
diskann-providers/src/storage/index_storage.rs	Updated async test to use new_memory().
diskann-providers/src/model/pq/pq_construction.rs	Updated tests to use new_memory().
diskann-providers/src/model/graph/provider/async_/simple_neighbor_provider.rs	Updated tests to use new_memory().
diskann-providers/src/model/graph/provider/async_/memory_vector_provider.rs	Updated tests to use new_memory().
diskann-providers/src/model/graph/provider/async_/memory_quant_vector_provider.rs	Updated tests to use new_memory().
diskann-providers/src/model/graph/provider/async_/inmem/scalar.rs	Updated tests to use new_memory().
diskann-providers/src/model/graph/provider/async_/fast_memory_vector_provider.rs	Updated tests to use new_memory().
diskann-providers/src/model/graph/provider/async_/fast_memory_quant_vector_provider.rs	Updated tests to use new_memory().
diskann-providers/benches/benchmarks_iai/copy_aligned_data_bench_iai.rs	Updated benchmark setup to use new_physical(...).
diskann-providers/benches/benchmarks/copy_aligned_data_bench.rs	Updated benchmark setup to use new_physical(...).
diskann-disk/src/storage/quant/pq/pq_generation.rs	Simplified test storage setup to new_memory() and generalized helper types.
diskann-disk/src/storage/quant/generator.rs	Updated test helpers to use new_memory() and generalized storage provider type params.
diskann-disk/src/storage/cached_reader.rs	Updated tests to use new_memory().
diskann-disk/src/build/builder/build.rs	Updated tests to use new_memory().
clippy.toml	Added disallowed-methods entry for VirtualStorageProvider::new_physical.

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