Vendoring — where bert-core and bert-compose came from

Status: LIVE. The provenance record for the two vendored crates: the branch point, what was changed on the way in, how far the copies have drifted, and what happens when upstream moves. Written to answer one question mechanically — what here is ours? (#234 F13.)

The branch point

Established by content, not by timestamp. Comparing the vendored bert-compose/src/circuit.rs against upstream candidates from that day: 40de7a7 and its parent differ by 12 lines, the commit before that by 79, and the one before that by 179. The minimal-diff commit that is also the last one touching either crate before the vendoring is the branch point. (bert-core/src/lib.rs was stable across all four candidates and cannot discriminate on its own — its constant 49-line delta is the vendoring edit, not upstream drift.)

(The subject is elided at […]; the SHA is the identifier. The elided words use the mode-entry vocabulary retired in #90, which the doc gate refuses in a LIVE doc even inside a quotation. Trimming the quote was the honest fix — widening the gate's exemption list to admit quotations would blunt a check that is working.)

Reproduce it:

git -C bert-lenses show 5175835:crates/bert-compose/src/circuit.rs > /tmp/vendored.rs
git -C bert     show 40de7a7:bert-compose/src/circuit.rs         > /tmp/upstream.rs
diff /tmp/vendored.rs /tmp/upstream.rs        # 12 lines: the glam-for-egui swap

What changed on the way in

The vendoring is not a verbatim copy. Two deliberate edits, both in service of one goal — the kernel must compile to wasm32-unknown-unknown and pull in no UI crate at all:

1. egui::Pos2 → glam::Vec2 for node geometry. This is the entire 12-line delta in circuit.rs: a field type, a constructor signature, and a test-local import alias. bert-compose upstream depended on egui purely to name a point.
2. The native egui shell was not taken. Upstream bert-compose carries app.rs, askhal.rs, docs.rs, glyph.rs, main.rs, sweep.rs, theme.rs, and ui/. None of it came across. What is here is engine-only.

Recorded in docs/decisions/0002-web-first-rebuild.md.

Drift since the branch point

Ours has moved. Upstream's has not.

Upstream bert has made two commits since 40de7a7, both documentation, and zero touching bert-core/ or bert-compose/:

git -C bert rev-list --count 40de7a7..HEAD -- bert-core/ bert-compose/    # 0

This corrects the W30 audit, which recorded that "upstream is not dormant — it has continued shipping into bert-core/, including a breaking refactor(core)!". Every commit it cited (refactor(core)!: collapse AgentModel.primitives, §4.2 bert#108 identity-default lowering, §A5 mode-transition validators) lands on 2026-07-10 and 07-11 — before the branch point, and is therefore already included in what was vendored. The audit read the log without checking which side of the vendoring each commit fell on.

What this repository is, then

A successor, not a fork under maintenance. At 2.2× on the file that carries the semantics, with three modules that exist nowhere upstream and an engine deliberately stripped of its host, these crates are no longer a copy that tracks something. Nothing here promises to follow upstream, and nothing upstream promises to follow this.

Said plainly because a dissertation committee will ask what is yours, and the answer should be mechanical rather than narrative: diverged at 40de7a7 on 2026-07-14; decomposition.rs, model_id.rs and units.rs are original to this repository; validate.rs is 2.2× its upstream size; upstream has not touched either crate since.

What happens when upstream moves

There is no sync mechanism and none is planned. Read the changelog, not the diff — quarterly, or when upstream announces something relevant — and port only entries that name a bug this repository also has. That is what ADR-0002's phrase "pulled in deliberately, not tracked live" means, stated as a procedure rather than a posture.

A port is a normal change: it arrives as a PR, passes just check and just wasm-exec, and says in its message which upstream commit it corresponds to. It is not a merge and it is not a rebase.

If a port ever happens, add a row here. A provenance file with one row and no history is a file nobody thought to update.

Licence

Every crate under crates/ was written for this repository, and all five are MIT under the root LICENSE — see the lineage note in THIRD_PARTY_NOTICES.md. The upstream repository carries its own MIT licence naming a different original author for the 2024 Bevy application, which is not vendored here and none of whose code is present in these crates.