# Support and verification matrix

RFC 8493 is an informational RFC defining BagIt 1.0. MoonBagIt implements a
documented UTF-8 / SHA-256 / SHA-512 subset. Unsupported bags are not reported
as valid; that result alone does not prove the bag violates the RFC.

| RFC section | Implemented checks | Remaining work |
| --- | --- | --- |
| 2.1.1 | Two ordered declaration lines, version 1.0, UTF-8, reject BOM | Other registered encodings and legacy versions |
| 2.1.2 | Required data directory, nested opaque payload | Host adapters beyond Node.js |
| 2.1.3 | One or more payload manifests, hex lengths/case, separator, every file exactly once, escaped filenames | Other algorithms and optional legacy checksum-tool quirks |
| 2.2.1 | Forbid payload/tagmanifest entries; include every payload manifest; verify raw-byte digests; warn on different optional tag sets | Wider compatibility fixtures |
| 2.2.2 | Metadata order/repetitions, continuation syntax; Payload-Oxum uniqueness, numeric syntax, counts; local receiving profiles | Wider receiving agreements |
| 2.2.3 | Absolute scheme tokens, nonnegative or unknown length, safe payload path, per-manifest membership, local size | Full URI grammar and separately authorized remote fetching |
| 2.2.4 | Arbitrary tag files checked if listed; content ignored | None within current host restrictions |
| 2.3 | LF, CR, CRLF; UTF-8 text without BOM | Other encodings |
| 2.4 | SHA-256/SHA-512; default SHA-512 creation; non-destructive manifest upgrade | Legacy algorithms |
| 3 | Separate completeness from hash validity; verify all checksums even if Oxum matches | Unsupported formats require another validator |
| 5 | Path containment, reject traversal/links/special files; no remote requests | Hostile concurrent mutation, sandboxing, signatures |
| 6 | Deterministic manifests; case/file/directory collisions, Windows device-name, character and length lint | Unicode normalization matching |

The library's `FileRecord` contract is trusted input from its host. A caller
that supplies fabricated digests can fabricate the result. The shipped CLI
computes streaming digests using Node's maintained cryptographic implementation.

## Independent verification

Test dependency: LibraryOfCongress/bagit-python, CC0. PyPI source release 1.9.0
archive SHA-256: `9455006c2d1df88be95ec1fccabc5ea623389589ea4c85b3d85bd256f29d7656`.
The local test installation built this exact source with version metadata
`0.0.0` because the isolated environment initially lacked its SCM build plugin;
this is a packaging metadata limitation, not modified validation code.

Its published source creates 0.97 bags. The reverse interoperability test uses
only ordinary UTF-8 filenames, updates the declaration, reloads the independent
Bag object and calls its own `save()` to recompute tag manifests. Ordinary
ASCII/Unicode filenames, spaces, binary payloads, empty payloads, SHA-256 and
SHA-512 are in the positive interoperability suite.

Both the published source and upstream snapshot passed the local positive
interoperability suite. The upstream snapshot at
`4bd2713cedbe1f8e634567c20ef0dded9622011d` natively creates BagIt 1.0; its
reverse test did not need the legacy declaration upgrade. Its local source
build uses explicitly supplied `0.0.0` distribution metadata because a GitHub
source archive does not carry the Git tag history needed by hatch-vcs. Source
identity is the pinned commit, not that synthetic packaging version.

The upstream released source `_encode_filename` / `_decode_filename` processes
CR/LF but not `%`. The current upstream source inspected at
`4bd2713cedbe1f8e634567c20ef0dded9622011d` creates 1.0 but retains that `%25`
decoding limitation. The percent-filename case is therefore a local normative
test plus an explicit **expected upstream rejection**, not a positive
interoperability claim. Neither upstream source was patched for these tests.

The project's own tests also exercise missing/extra files, corrupt payload and
tag bytes, multiple-manifest coverage, BOM and malformed UTF-8, metadata
injection, path escapes, no-overwrite behavior and unsupported input. They are
not a substitute for running an external full BagIt conformance suite.

The pinned LibraryOfCongress/bagit-conformance-suite revision
`9ab48705c06664f9f419ca740c728c9f89a61e7c` contains five v1.0 fixtures, all run
without rewriting their bytes by `scripts/conformance.py`. Legacy fixture
directories are deliberately not presented as supported BagIt versions.