---
title: "modelcheck-library-discovery-changes — Mova code model"
description: "Mova code model of tools/modelcheck/src/lib.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/tools/modelcheck/src/lib.rs.groupant/discovery-changes.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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# modelcheck-library-discovery-changes

The groupant beside tools/modelcheck/src/lib.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:** [`tools/modelcheck/src/lib.rs`](https://github.com/ElamurAI/mova-free/blob/main/tools/modelcheck/src/lib.rs)
- **source SHA-256:** `0a09fdb807efa690…`
- **covers:** Sorted Git discovery, binary membership, inventory and changed-source gate (bytes 4711–9931)
- **part of:** [modelcheck-library](https://md.groupants.elamur.ai/free/en/mova/tools/modelcheck/src/lib.rs.groupant/)
- **repository folder:** [`tools/modelcheck/src/lib.rs.groupant/discovery-changes.groupant`](https://github.com/ElamurAI/mova-free/tree/main/tools/modelcheck/src/lib.rs.groupant/discovery-changes.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 | [forward](#forward) |
| **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** | finite native evidence | [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 relational specification | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial relational specification | [reverse_reconstruction](#reverse-reconstruction) |
| `sorted_membership_equivalence` | sorted_membership_equivalence | partial relational specification | [sorted_membership_equivalence](#sorted-membership-equivalence) |
| `directory_count_conservation` | directory_count_conservation | partial relational specification | [directory_count_conservation](#directory-count-conservation) |
| `changed_set_projection` | changed_set_projection | partial relational specification | [changed_set_projection](#changed-set-projection) |
| `comparison_budget` | comparison_budget | partial relational specification | [comparison_budget](#comparison-budget) |

## Model text


### descriptant

#### Sorted Git discovery, binary membership, inventory and changed-source gate groupant

Epoch 2026-10-31: materialized a scoped view after full-source review. Git ls-files -z cached/others exclude-standard feeds a BTreeSet. Membership returns binary_search success on that sorted list. Inventory verifies registered paths, confines and hashes files, and accumulates ancestor directory counts. Changed inventory rejects option-like base before inventory, then unions surviving diff/untracked .rs paths.

Discovery order is strict Rust String order and duplicate paths collapse. Membership equals the old existential scan only under sorted order. Directory registered<=total; missing=total-registered. Deleted diff paths are omitted by is_file; inventory may already fail on tracked missing files.

Useful prior epochs remain in the parent descriptant. This child uses exact byte anchors and the same whole-source hash: editing unrelated bytes also invalidates its binding. The fragment is a partial structural/behavior model, not a proof. No executable percentage surrogate is supplied: categorical gates have no defined useful loss metric; any future profile must use supported caps 1, 2, 5 or 10 percent with explicit domain and evidence.

### catalog

Wave33 historical scope and evidence follow. Current source hashes and refreshed ranges are in manifest.json; wave34 refinements and evidence are at the source root.

## Sorted Git discovery, binary membership, inventory and changed-source gate typed models

Subject/revision: source SHA-256 in manifest; scope [3699 , 8919). Domain is one completed scoped call on a fixed snapshot with adequate resources, unless narrowed below. Observation includes return/error and declared filesystem effects. Models are source-derived partial relational constraints; complements are inner exclusion hypotheses, converse relations retain compatible-input ambiguity. No universal proof or inverse executor is claimed. Evidence: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Mutation evidence and limits are recorded in ../wave33-evidence.md.

### behavior_complement

Exclude successful changed calls with empty or option-prefixed base and inventory success with registered paths absent from discovery or canonical source outside root. Checks are never executed.

Oracle: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Fixed source scope and the stated domain are required; finite checks do not establish untested generality.

### reverse_reconstruction

A report constrains discovered paths, source digests, model IDs and directory counts; ignored files, source bytes beyond digest identity, Git history and filesystem timing remain ambiguous.

Oracle: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Fixed source scope and the stated domain are required; finite checks do not establish untested generality.

### sorted_membership_equivalence

For strictly sorted F from rust_files, binary_search(F,q).is_ok iff exists i:F[i]=q. Empty, first/last, gaps, prefixes and Unicode ordering obey the same relation; arbitrary unsorted callers are outside the helper contract.

Oracle: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Fixed source scope and the stated domain are required; finite checks do not establish untested generality.

### directory_count_conservation

Each discovered path adds one to every lexical ancestor directory and adds registered indicator to the second count. Totals are sums over ancestry incidence, not disjoint directory partitions.

Oracle: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Fixed source scope and the stated domain are required; finite checks do not establish untested generality.

### changed_set_projection

For fixed repository snapshot, changed=(diff(base) union untracked) intersect existing_file. missing_changed=changed minus registered_sources. A report cannot recover which producer supplied a path occurring in both.

Oracle: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Fixed source scope and the stated domain are required; finite checks do not establish untested generality.

### comparison_budget

For Q queries and P sorted paths, binary search requires O(Q log(P+1)) comparisons and constant search workspace. Timings compare the actual helper with old linear predicate; discovery/hash/JSON/ancestor costs are excluded.

Oracle: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository. Fixed source scope and the stated domain are required; finite checks do not establish untested generality.

### tests

#### Native correspondence

Exact named checks: wave33_tests::sorted_membership_matches_linear_reference_and_measures_cost; tests::changed_gate_rejects_revision_options_before_touching_a_repository.

See ../wave33-evidence.md for current repeated profiles, actual production mutants and scope limits. AST generation alone is not behavioral evidence. Each reference test body was read before execution.

### forward

#### Scoped forward model

Sorted Git discovery, binary membership, inventory and changed-source gate

Git ls-files -z cached/others exclude-standard feeds a BTreeSet. Membership returns binary_search success on that sorted list. Inventory verifies registered paths, confines and hashes files, and accumulates ancestor directory counts. Changed inventory rejects option-like base before inventory, then unions surviving diff/untracked .rs paths.

### invariant-and-cost

#### Invariant and cost

Discovery order is strict Rust String order and duplicate paths collapse. Membership equals the old existential scan only under sorted order. Directory registered<=total; missing=total-registered. Deleted diff paths are omitted by is_file; inventory may already fail on tracked missing files.

Discovery sorting O(P log P) comparisons; membership Q queries O(Q log P) rather than O(QP), multiplied by compared prefix lengths. Inventory hashes total bytes B and visits directory depth D per path. Changed invokes inventory plus two Git processes; no IO speed gain follows.