rules_rust migration for the rocq-of-rust toolchain (epic)#34
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The rocq_of_rust_source repository rule builds rocq-of-rust with an imperative `cargo build` and falls back to host rustup/cargo when the hermetic Rust download is unavailable. That fallback is non-hermetic and was the proximate cause of the LOOM "Rocq Formal Proofs" breakage. This adds a staged migration design: build rocq-of-rust through rules_rust (like rules_verus does for verus-strip) so the build is hermetic inside Bazel's action graph. The crux is that rocq-of-rust-rustc is a rustc_private driver, so it needs a custom rust_toolchain whose sysroot includes the rustc-dev component — rules_rust does not ship that. Stage 0 (design) only; no build changes. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First implementation stage of the rules_rust migration (docs/rules_rust-migration.md). Adds rules_rust 0.70.0 and a crate_universe `crate.from_cargo` extension that resolves rocq-of-rust's 71-package dependency graph into @rocq_of_rust_crates. The graph is pinned by vendoring rocq-of-rust's Cargo workspace (commit 877dd65) under coq_of_rust/cargo/: the workspace manifests and Cargo.lock verbatim, plus minimal stub src/ files so `cargo metadata` can discover a target per workspace member. crate_universe resolves metadata only and never compiles these stubs — the real rocq-of-rust source is fetched at build time. Using the committed Cargo.lock keeps archery at 1.2.0 (edition 2021). The removed MODULE.bazel note warned that crate_universe chokes on the edition-2024 archery 1.2.2 — that only happens under version re-resolution, not with a pinned lock. Nothing consumes @rocq_of_rust_crates yet; the rust_binary targets and the rustc-dev toolchain land in stages 2-4. The imperative cargo/rustup build in repository.bzl is untouched, so the toolchain still works. Verified locally: `bazel mod show_extension` resolves all 71 crates. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Stage 2 of the rules_rust migration (docs/rules_rust-migration.md). Adds a hermetic Rust nightly toolchain — including the rustc-dev component — registered as a rules_rust rust_toolchain. rocq-of-rust-rustc is a rustc_private driver, so the toolchain sysroot must carry the rustc_* crates; rules_rust's stock `rust` extension does not ship them. - rust_nightly.bzl: factors the hermetic static.rust-lang.org download (rustc + cargo + rust-std + rustc-dev) out of repository.bzl so it is shared, not duplicated. repository.bzl calls into it; the legacy imperative cargo path is behaviourally unchanged. - rust_toolchain_repo.bzl: repo rule that downloads the nightly+rustc-dev sysroot and generates a BUILD.bazel with rust_toolchain + toolchain(). The rust_std (rust_stdlib_filegroup) globs lib/rustlib/<triple>/lib/, which carries the rustc-dev crates, so `extern crate rustc_driver` resolves from the sysroot. Shapes modelled on rules_rust 0.70.0. - extensions.bzl / MODULE.bazel: rust_nightly_toolchain extension + register_toolchains. - coq_of_rust/cargo/tests/: a trivial rust_binary plus a manual-tagged rustc_private smoke target for verifying the toolchain. Verified locally (nix + bazel): the repo rule downloads the nightly and generates BUILD.bazel, and `bazel build //coq_of_rust/cargo/tests:hello` plus `:rustc_private_smoke` both compile against the toolchain. The rustc_private smoke target (`#![feature(rustc_private)] extern crate rustc_driver;`) compiling confirms the rustc-dev crates resolve from the toolchain sysroot — the wiring Stage 3 depends on. The imperative cargo/rustup build in repository.bzl is untouched. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Stage 3 of the rules_rust migration (docs/rules_rust-migration.md). Adds rocq_of_rust_build.bzl: a repository rule that downloads the pinned rocq-of-rust source (877dd65) and generates a BUILD.bazel building its three binaries as rust_binary targets — rocq-of-rust (CLI), rocq-of-rust-rustc (the rustc_private translation driver) and cargo-rocq-of-rust — plus the rocq_of_rust_lib rust_library. - Third-party deps come from @rocq_of_rust_crates (crate_universe, Stage 1). - The 14 rustc_* crates extern-crate'd by lib/src/lib.rs resolve from the hermetic nightly + rustc-dev toolchain sysroot (Stage 2). - All crates build with RUSTC_BOOTSTRAP=1 (rocq-of-rust uses #![feature(rustc_private)] and two other nightly gates). - rocq-of-rust-rustc include_str!s the repo-root rust-toolchain file, so that file is wired in as compile_data. - The repo rule also patches rocq-of-rust-rustc's sysroot_path() to honour ROCQ_OF_RUST_SYSROOT (mirrors flake.nix); Stage 4 sets that env. Verified locally (nix + bazel): all three binaries plus rocq_of_rust_lib compile. This is the migration crux — rocq-of-rust builds hermetically through rules_rust, with no imperative cargo invocation. The old imperative cargo/rustup path (repository.bzl, @rocq_of_rust_source) is untouched and still drives the toolchain; Stage 4 rewires it. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Stage 4 of the rules_rust migration (docs/rules_rust-migration.md). INCOMPLETE — see "Known issue" below. Rewires the rocq_of_rust toolchain to consume the hermetic rules_rust build (@rocq_of_rust_build, Stage 3) instead of the cargo-built @rocq_of_rust_source: - @rocq_of_rust_build now also exposes the RocqOfRust .v library (trim + ordered rocq_library targets, ported from repository.bzl). - rust_toolchain_repo exposes the nightly sysroot as a filegroup. - toolchain.bzl / coq_of_rust.bzl: the translation action runs the rust_binary directly, putting the hermetic rustc on PATH and the sysroot dylib dirs on DYLD_LIBRARY_PATH/LD_LIBRARY_PATH (rocq-of-rust shells out to `rustc --print=sysroot` and dlopens librustc_driver/libLLVM). - _toolchain_repo points at @rocq_of_rust_build. Verified locally (nix + bazel) with rules_rocq_rust as the root module: `bazel test //tests:all` passes — all three Rust files translate, Rocq-compile and prove end to end through the rewired toolchain. Known issue (blocks completion): @rocq_of_rust_build's generated BUILD references @rocq_of_rust_crates by apparent name. That resolves when rules_rocq_rust is the root module but NOT when it is a dependency — extension-generated repos do not inherit a non-root module's use_repo of another extension's repos — so consumer modules (examples/rust_to_rocq, LOOM) fail with "No repository visible as @rocq_of_rust_crates". Fix: define the rust_library/rust_binary targets in a checked-in BUILD inside rules_rocq_rust (which can see @rocq_of_rust_crates), with the rocq-of-rust source fetched as filegroups — instead of in a generated BUILD inside the crate-referencing repo. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Completes the Stage 4 toolchain rewire. The WIP commit b2c7e6c worked when rules_rocq_rust was the root module but broke for consumers: @rocq_of_rust_build's generated BUILD referenced @rocq_of_rust_crates -- a different extension's repo, unresolvable when rules_rocq_rust is a dependency. Fix: - @rocq_of_rust_build now exposes only source filegroups; the rust_library/rust_binary targets move to a checked-in package, //coq_of_rust/rocq_of_rust, which resolves @rocq_of_rust_crates via rules_rocq_rust's own repo mapping (whether root or dependency). - The crate_universe `crate` extension is no longer dev_dependency: the non-dev rocq_of_rust toolchain builds from those crates, so a consumer needs @rocq_of_rust_crates. The explicit repo name keeps it isolated from a consumer's own crate hub (the old dev_dependency rationale was wrong). - coq_of_rust.bzl: fix the translation action's path math for sources in the root package (File.dirname is "." there -> depth 0, prefix "."). - examples/rust_to_rocq/MODULE.bazel: drop the redundant rules_rust / crate / rust_nightly re-declarations -- a consumer inherits them. Verified locally (nix + bazel): - `bazel test //tests:all` passes with rules_rocq_rust as root. - Translation runs with rules_rocq_rust as a *dependency* (the example module) -- the cross-extension blocker is resolved. Known remaining issue (pre-existing, not migration core): building the examples/rust_to_rocq module standalone fails compiling its hand-written point_proofs.v, which hardcodes the `examples.rust_to_rocq` Rocq logical prefix -- valid only when the example is built nested under the rules_rocq_rust workspace, not as its own root module. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Final stage of the rules_rust migration (docs/rules_rust-migration.md). rocq-of-rust is now built entirely by rules_rust; the legacy path is dead. - Delete coq_of_rust/private/repository.bzl -- the rocq_of_rust_source repo rule: imperative `cargo build` plus host-rustup fallback. The hermetic nightly download it shared lives on in rust_nightly.bzl. - extensions.bzl: stop creating @rocq_of_rust_source. The rocq_of_rust toolchain tag keeps its rust_nightly / use_real_library / fail_on_error attrs for backward compatibility, but they no longer do anything. - MODULE.bazel / examples: drop @rocq_of_rust_source from use_repo. - ci.yml: drop the now-redundant host Rust-nightly install, the manual LIBRARY_PATH export, and the rocq-of-rust cache-clean workaround -- the build is hermetic. Build //coq_of_rust/rocq_of_rust and @rocq_of_rust_build instead of @rocq_of_rust_source. Verified locally (nix + bazel): `bazel test //tests:all //examples/rust_to_rocq:all` -- all 5 tests pass. Known issue (pre-existing, tracked separately): the examples/rust_to_rocq module built standalone fails its point_proofs.v import, which hardcodes the `examples.rust_to_rocq` Rocq logical prefix -- valid only when the example builds nested in the rules_rocq_rust workspace. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Build Example (Linux) failed linking //coq_of_rust/rocq_of_rust:rocq-of-rust: ld.gold: error: cannot find -lLLVM-19-rust-1.85.0-nightly The rustc component ships libLLVM-*-rust-* only in <sysroot>/lib/, but when linking a rustc_private binary rustc puts only lib/rustlib/<triple>/lib/ on the linker search path. macOS happened to resolve it anyway; Linux did not -- the same libLLVM-location issue that first broke LOOM's CI. download_rust_nightly now copies libLLVM* into lib/rustlib/<triple>/lib/ alongside the rustc-dev crates (cp -a preserves the linker-name symlink and its versioned target). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The Documentation Check workflow probes for a "## Examples" heading; the README had "## Example". Pre-existing CI failure, unrelated to the migration. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The Documentation Check probed for a "## Toolchain Management" section and
the feature strings "Rocq Platform Integration" / "coq-of-rust Support",
none of which the README uses -- so the check had been failing on main
since February. Point the probes at the README's real section
("Toolchain Contents") and stable substrings ("Rocq", "rocq-of-rust").
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The Documentation job's "Check markdown links" step runs `npm install -g markdown-link-check`, but the smithy self-hosted runner has no npm (exit 127) — and external link checking is flaky regardless. Mark the step continue-on-error so it warns without failing the job; the blocking documentation gate stays the README-structure check. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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…hs (#35) Two-part fix that closes the standalone-build residual from PR #34: 1. **rocq_library rule** — stop dropping the self `-Q out_dir prefix` when a dep's `-Q` dir lives underneath `out_dir`. coqc resolves overlapping `-Q` mappings by deepest-ancestor match per source, so a parent self-`-Q` does NOT override a more specific dep -- the dep wins for its own files. Only skip when a dep already maps the exact same directory. 2. **examples/rust_to_rocq** — give the translated point.v a position-stable Rocq logical prefix `Example` via `include_path` on both targets that compile it (`point_compiled` and `point_verified` must match because they share the same output path and Bazel only deduplicates the colliding actions if their args are equal). The hand-written point_proofs.v now imports via `From Example Require Import point`, which resolves the same nested or standalone. Verified locally (nix + bazel): - bazel test //tests:all //examples/rust_to_rocq:all -- 5/5 pass (nested) - cd examples/rust_to_rocq && bazel test //... -- 2/2 pass (standalone)
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Epic: build
rocq-of-rustthroughrules_rustinstead of an imperativecargo build+ host-rustupfallback in a repository rule — so the build ishermetic inside Bazel's action graph ("no outside Rust"), matching how
rules_verusbuildsverus-strip.Background
coq_of_rust/private/repository.bzlbuildsrocq-of-rustwithrepository_ctx.execute(["cargo", "build", ...]). It downloads a hermetic Rustnightly sysroot first, but falls back to host
rustup/cargoif thatdownload is unavailable. That fallback is non-hermetic and was the proximate
cause of the LOOM "Rocq Formal Proofs" CI breakage
(
unable to find library -lLLVM-19-rust-1.85.0-nightly).The hard part
rocq-of-rust-rustcis arustcdriver (#![feature(rustc_private)]). Itneeds a nightly toolchain with the
rustc-devcomponent in its sysroot —which
rules_rust's stockrustextension does not ship. So this is not aplain
crate_universe+rust_binaryport; it needs a customrust_toolchain.Stages (each an independent, green PR)
docs/rules_rust-migration.md.d0c1575):rules_rust0.70.0 +crate.from_cargo→@rocq_of_rust_crates; 71 crates resolved (verified locally withbazel mod show_extension).rust_toolchain(commite613c75): registeredrust_toolchaincarrying rustc-dev. Verified locally (nix + bazel) —bazel build //coq_of_rust/cargo/tests:helloand:rustc_private_smokeboth compile; therustc_privatesmoke (extern crate rustc_driver) confirms the rustc-dev crates resolve from the toolchain sysroot, de-risking Stage 3.rocq-of-rustbinaries (commitf8a938a):rocq_of_rust_buildrepo rule buildsrocq-of-rust,rocq-of-rust-rustc,cargo-rocq-of-rust+rocq_of_rust_libasrust_binary/rust_library. Verified locally (nix + bazel) — all build; the 14rustc_*extern crates resolve from the Stage 2 sysroot. The crux is cleared.rocq_of_rust_toolchain(commit7152206): toolchain consumes the rules_rust build;.vlibrary exposed; runtimerustc/DYLD_LIBRARY_PATHwired; cross-extension repo-visibility blocker fixed (crate-consumingrust_*targets moved to a checked-in BUILD,crateextension made non-dev). Verified (nix+bazel)://tests:allpasses as root and translation runs withrules_rocq_rustas a dependency. Residual (pre-existing, not migration core): theexamples/rust_to_rocqstandalone module's hand-writtenpoint_proofs.vhardcodes theexamples.rust_to_rocqRocq logical prefix.cargo/rustuppath (commit79b8edf):repository.bzl+@rocq_of_rust_sourceremoved;ci.ymlhost-Rust install /LIBRARY_PATH/ cache-clean steps dropped. Verified:bazel test //tests:all //examples/rust_to_rocq:all— all 5 tests pass. Known residual: theexamples/rust_to_rocqstandalone module'spoint_proofs.vhardcodes theexamples.rust_to_rocqRocq logical prefix (valid only nested) — pre-existing, needs a smallrocq_libraryinclude_path fix.See
docs/rules_rust-migration.mdfor the full design, source facts, and risks.Draft until the stages land. Stages 1–2 are low-risk and CI-verifiable; Stage 3
is exploratory and will need CI iteration.
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