[dannycjones]

Which issue does this PR close?

• Closes V2 manifest entry data file struct schema has V3 fields defined, although never produced #3532.

What changes are included in this PR?

Remove V3 row lineage fields from the manifest schema.

Note, the manifest serde is reworked a little. New types are introduced for both V2 and V3, which mostly delegates to the V2V3 (renamed from V2) type. I think this makes a more consistent way to interact with these types, with the fact that they're mostly equivalent an implementation detail in the reader/writer module.

A few bits for format versions was not wired up - not really any changes but code reads correct now.

Are these changes tested?

Existing tests provide a lot of coverage. I've introduced new tests to assert the list of expected fields for V1, V2, and V3.

AI Disclosure

I proposed the change and used Claude Code to draft the changes. Reworked it a bit myself to get it into a nicer long term shape.

[Copilot]

🟢 Approval recommended

No active review issues were identified for the version-specific manifest schema and serialization changes.

No open issues 🎉

What changed in this PR

Addresses #3532 by excluding V3-only fields from V2 manifest data-file schemas while preserving V3 support.

Changes:

• Separates V2 and V3 manifest schemas and serialization paths.
• Passes the requested format version through standalone data-file serialization.
• Adds field-list assertions for V1, V2, and V3 manifests and updates reader tests.

File	Description
crates/​iceberg/​src/​spec/​manifest/​writer.rs	Selects version-specific schemas and serializers; adds schema field-list tests.
crates/​iceberg/​src/​spec/​manifest/​mod.rs	Separates V2/V3 deserialization and adjusts version-specific test fixtures.
crates/​iceberg/​src/​spec/​manifest/​entry.rs	Removes V3-only fields from the V2 schema and adds a V3 manifest schema.
crates/​iceberg/​src/​spec/​manifest/​data_file.rs	Uses the requested format version when serializing data files.
crates/​iceberg/​src/​spec/​manifest/​_serde.rs	Introduces V2/V3 wrappers around shared manifest-entry serialization logic.

_{Review effort: Balanced}