Elamur Groupantsmathlib-fetch-archive
The groupant beside tools/mathlib/src/fetch.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial | approximant |
| ast | partial | ../syntax.json |
| cost | partial | invariant-and-cost |
| descriptant | present | descriptant |
| invariant | partial | invariant-and-cost |
| tests | bounded checks | tests |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
behavior_complement | behavior_complement | partial source derived model | behavior_complement |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
extension_filter | extension_filter | partial source derived model | extension_filter |
header_projection | header_projection | partial source derived model | header_projection |
empty_commit | empty_commit | partial source derived model | empty_commit |
inclusive_entry_cap | inclusive_entry_cap | partial source derived model | inclusive_entry_cap |
Model text
descriptant
mathlib-fetch-archive
compact_tar_gz streams regular tar entries, keeps recognized text extensions with size<=5<<20, rewrites headers, syncs temporary gzip and renames only when kept>0.
Epoch 2026-10-31
Prospective model retained before changes. Existing production bytes are preserved; additions are bounded inline tests. Nine source groupants expose ingestion and routing boundaries; typed children bind exact source bytes and reuse their parent syntax projection. Native tests run twice per profile; behavior mutants run as compiled source changes and exact bytes are restored before positive checks.
Important retained observation: network-looking helpers are not all pure (DNS inside github_host and books build); selection deliberately excludes those effects. Mixed-format manifest order is not deterministic, and error paths do not imply rollback.
No network/DNS/download, real catalog/corpus/model/teacher or database execution. Effect paths are source-derived; finite helper tests are not universal verification. No executable percentage surrogate or speed claim; future caps require metric/domain/reference and remain 1/2/5/10%.
approximant
Forward relation
compact_tar_gz streams regular tar entries, keeps recognized text extensions with size<=5<<20, rewrites headers, syncs temporary gzip and renames only when kept>0.
Model observations include returns, retained state and ordered partial effects; on external failures the successful-prefix relation replaces a total-function claim.
catalog
behavior_complement
Subject: mathlib-fetch-archive, source SHA-256 9a892fd61299338f640f9d8d08471ef7f09cac19235ad80b90d894a12489996d; finite transition observation.
Regular .png entries and text entries above 5 MiB never appear in successful compact output; kept=0 removes temporary file and cannot create dst by rename.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
reverse_reconstruction
Subject: mathlib-fetch-archive, source SHA-256 9a892fd61299338f640f9d8d08471ef7f09cac19235ad80b90d894a12489996d; finite transition observation.
Given compact archive, antecedents include arbitrary excluded binary/nonregular entries interleaved with retained text and differing discarded metadata. Retained order and contents constrain regular kept entries; original gzip bytes are not reconstructible.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
extension_filter
Subject: mathlib-fetch-archive, source SHA-256 9a892fd61299338f640f9d8d08471ef7f09cac19235ad80b90d894a12489996d; finite transition observation.
Extension is final path suffix lowercased and membership is exact in fourteen strings. Uppercase TEX passes; .tex.png fails. compacts_sources tests text/figure selection.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
header_projection
Subject: mathlib-fetch-archive, source SHA-256 9a892fd61299338f640f9d8d08471ef7f09cac19235ad80b90d894a12489996d; finite transition observation.
Kept entries have mode 0644, regular type, original size and mtime or zero. Ownership and other original header data are projected away.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
empty_commit
Subject: mathlib-fetch-archive, source SHA-256 9a892fd61299338f640f9d8d08471ef7f09cac19235ad80b90d894a12489996d; finite transition observation.
Completion closes gzip and syncs before checking kept. Zero kept removes tmp and returns None; caller retains original. Error cleanup is not uniformly guaranteed.
Domain: stated source predicates, bounded inputs and available resources; arithmetic assumptions and external effect gaps as in the invariant. Operator is the stated relation/projection; complement is a source-derived inner exclusion, reverse retains compatible antecedents. Other views are source-derived partial constraints, not inverse laws.
Evidence: tests.md identifies executed helpers and unexecuted paths. No universal guarantee follows from the finite fixtures.
inclusive_entry_cap
The text-size comparison admits exactly 5*2^20 bytes and rejects the next size. The cap is per retained header entry and does not limit total archive bytes, regular dropped entries or decompression work. Boundary execution remains a gap; fixture exercises only tiny files.
Subject and source identity: manifest.json. Domain: scoped forward/invariant; relation is source-derived and partial. Evidence: tests.md distinguishes actual checks from unexecuted effect paths; finite fixtures do not prove all inputs.
tests
Bounded evidence
Selected actual source checks:
- mathlib::fetch::tests::compacts_sources
- mathlib::fetch::tests::ext_and_licenses
- mathlib::fetch::wave33::list_signature_hash_and_existing
These checks are file-level evidence; fragment branches not reached by these names remain source-derived.
External wave33 mathlib receipt retains native-commands.json, numeric statuses, raw debug/release logs, sorted exact outcomes, mutation logs and original/restored hashes. Seventeen named checks pass twice per profile; six production behavior mutants reject in both profiles, with restored positives. Source syntax is regenerated twice after formatting and compared byte-for-byte. Structural validation tests bindings, not Rust semantics.
No network/DNS/download, real catalog/corpus/model/teacher or database execution. Effect paths are source-derived; finite helper tests are not universal verification. No executable percentage surrogate or speed claim; future caps require metric/domain/reference and remain 1/2/5/10%.
invariant-and-cost
Invariant and cost
Invariant
Nonregular entries are ignored, not counted dropped. kept+dropped equals regular entries encountered on successful scan. No archive path is extracted to disk.
Cost
O(decompressed input plus compression work); bounded streaming buffers, no aggregate decompressed-size bound.
Domain and gaps
No network/DNS/download, real catalog/corpus/model/teacher or database execution. Effect paths are source-derived; finite helper tests are not universal verification. No executable percentage surrogate or speed claim; future caps require metric/domain/reference and remain 1/2/5/10%.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/tools/mathlib/src/fetch.rs.groupant/archive.groupant/