External Reproduction¶

This page is the protocol for an independent reviewer to reproduce mixle’s claims from a clean environment (worklist E14). It is deliberately runnable without insider knowledge: two commands, a captured environment, and deterministic outputs to compare.

Why a receipt¶

A reproduction is only meaningful if two people can compare the same thing. mixle’s claims are backed by seeded, deterministic computations, so an independent run on the same version must produce identical numbers. The installed mixle-reproduce command captures the artifact, environment, expectations, measurements, and per-check verdicts as a JSON receipt. It exits nonzero unless the wheel identity, installed-content hashes, and every required check pass.

The protocol¶

Download and clean-install the exact artifact. Keeping the wheel is necessary because an installed Python distribution does not retain the byte digest of the wheel archive from which it came:

python -m venv repro-env
repro-env/bin/pip download --no-deps --only-binary=:all: "mixle==<version>" --dest artifacts
repro-env/bin/pip install artifacts/mixle-<version>-*.whl

Emit a receipt. Run the command shipped in that wheel and give it the retained artifact:
```
repro-env/bin/mixle-reproduce --wheel artifacts/mixle-<version>-*.whl --out receipt.json
```
The command verifies the wheel’s SHA-256, name and version, its embedded source commit/tree, the hashes of installed files named by RECORD, the deterministic claim checks, and – decisively – that the supplied wheel IS the distribution executing: the installed package’s embedded build provenance must equal the wheel’s, and every hashed entry in the wheel’s RECORD must match the installed RECORD. Version equality alone is not identity; without the binding, any other clean wheel of the same version could be presented as the receipt’s subject while different bytes executed. A development checkout may instead use python scripts/reproduce.py --source-tree; that explicitly binds the receipt to the repository containing the script and never consults the caller’s ambient Git repository.

Scope. The installed command runs the self-contained claim checks above and nothing else; its receipt says so in a scope field. The four reproduction-bundle entries (gallery-univariate, gallery-structured, production-provenance, scaling-backend) are NOT part of it – the wheel ships neither the bundle nor its inputs. Replaying them is a separate, source-bound step from a checkout of the same commit:
```
python scripts/run_repro_entry.py --entry gallery-univariate
```
run once per entry, attaching each validated receipt. A complete independent replay therefore consists of one installed-command receipt plus four entry receipts.
Require success, then compare. The process exit status and receipt-level passed must both indicate success. Each check records its observed value, required value, tolerance, and verdict. Compare the wheel SHA-256 with the digest attached to the GitHub Release; the environment block makes dependency/platform differences attributable.
Full suite (optional, stronger). For a complete reproduction, run the correctness gate against the clean install:
```
repro-env/bin/python -m pytest -m "not optional and not benchmark"
```
and, with the optional backends installed, the optional and benchmark tiers. This is the same suite CI runs; the release checklist records the exact commands and the result counts for the released commit.

What a mismatch means¶

A failed check or nonzero exit is a failed reproduction, not an ordinary receipt. Treat it as a bug and retain both receipts; their artifact and environment blocks localize the discrepancy.
A ``checks`` difference across versions is expected when a release intentionally changes behavior; it must correspond to a changelog entry and an entry in the release decision log (release-checklists/0.8.2-decisions.md in the repository; decisions D-0001..D-0211 in release-checklists/0.8.0-decisions.md remain in force).

The receipt’s determinism is itself gated by mixle/tests/reproduce_receipt_test.py, so the reproduction path cannot silently rot.