id: ADR-0038 title: Add pse-ipopt-sys, pse-buildinfo, xtask, benches and five test crates to the workspace layout status: accepted date: 2026-09-13 deciders: [paul-heyse] level: decision principles: [DM-31, DM-53, DM-60, DM-48] blueprint: [§3.2, §24.1, §24.3, §18.3] review: not-required: the layout additions follow from decisions the reviews already drove (R2-5 pins, F10 probes); no finding names §3.2’s crate list evidence: Proposed supersedes: [] superseded-by: null revisit: A sixth test family is needed, or xtask grows logic that belongs in a shipped crate verification: tests/governance/tests/every_crate_registered.rs (every workspace member appears in the blueprint §3.2 layout and carries the pse- prefix); rust / test

ADR-0038: Add pse-ipopt-sys, pse-buildinfo, xtask, benches and five test crates to the workspace layout

Context

Blueprint §3.2 lists the 23 pse-* crates, python/, packages/reference/ and tests/golden/. The §24.1 test matrix names six test families and §18.3 requires a -sys crate with committed bindgen output, none of which appear in the layout block.

Scope

Binds the workspace membership. This record amends blueprint §3.2 rather than deviating from it — the additions are written into the layout block with a > Decision: ADR-0038 marker — which is why its level is decision and not should-deviation; the amendment is carried as revision 4 in the revision history.

Drivers

A test family that is not a crate cannot be run by cargo nextest; governance tests need cargo_metadata and so need a crate; xtask is how the justfile stays a one-line surface over logic that needs Rust APIs; the Ipopt links key must live in its own -sys crate.

Options

Put governance tests in each crate’s tests/ — rejected: they are workspace-wide assertions and would be duplicated 23 times. Make xtask a shell script — rejected: cargo metadata parsing, JSON and cross-platform behaviour are Rust’s job.

Outcome

The workspace adds crates/pse-ipopt-sys/ (links = "ipopt", bindgen output committed), crates/pse-buildinfo/ (lockfile hashes, rustc version, profile, git sha), xtask/, benches/ (pse-benches, criterion), and tests/{governance,engine,conformance,lifecycle,structural}/ as member crates named pse-tests-<name>. tests/golden/ stays data, not a crate. The ipopt feature is default-on in pse-backend-native, pse-runtime and pse-py, with pse-ipopt-sys optional so --no-default-features checks cleanly; phase-0 wheels build without it.

Consequences

None of the added crates is ever published: publish = false stays set for xtask, benches, tests/* and pse-py.

Compensating controls

every_crate_registered asserts the workspace membership matches the blueprint layout block, so the two cannot drift.

Confirmation

rust / clippy runs once with default features and once with --no-default-features, which is what keeps the optional -sys crate honest.

Pros and cons

Five test crates is more manifests than one; it is also what makes the §24.1 matrix runnable and separately profiled in .config/nextest.toml.

More information

Blueprint §3.2 (workspace layout, revision 4), §24.1 (test layers), §24.3 (benchmarks), §18.3 (Ipopt -sys crate); ADR-0028.

Status history

• 2026-09-13 — accepted with the repository-seeding pull request (backfilled from blueprint revision 3).