---
title: "mathlib-fetch-archive — Mova code model"
description: "Mova code model of tools/mathlib/src/fetch.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/mathlib/src/fetch.rs.groupant/archive.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

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# mathlib-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

- **kind:** groupant_fragment
- **status:** partial source bound model
- **source:** [`tools/mathlib/src/fetch.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/mathlib/src/fetch.rs)
- **source SHA-256:** `9a892fd61299338f…`
- **covers:** 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. (bytes 7072–8717)
- **part of:** [mathlib-fetch](https://md.groupants.elamur.ai/free/en/mova/tools/mathlib/src/fetch.rs.groupant/)
- **repository folder:** [`tools/mathlib/src/fetch.rs.groupant/archive.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/mathlib/src/fetch.rs.groupant/archive.groupant)
- **repository commit:** `855da7bd4a7b`

> **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](#approximant) |
| **ast** | partial | `../syntax.json` |
| **cost** | partial | [invariant-and-cost](#invariant-and-cost) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [invariant-and-cost](#invariant-and-cost) |
| **tests** | bounded checks | [tests](#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](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |
| `extension_filter` | extension_filter | partial source derived model | [extension_filter](#extension-filter) |
| `header_projection` | header_projection | partial source derived model | [header_projection](#header-projection) |
| `empty_commit` | empty_commit | partial source derived model | [empty_commit](#empty-commit) |
| `inclusive_entry_cap` | inclusive_entry_cap | partial source derived model | [inclusive_entry_cap](#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%.