{ "number": 36709, "input_hash": "4eaf4498b4b31f5f", "model": "ledger", "prompt_hash": null, "created": "2026-11-01T01:16:00+00:00", "result": { "summary": "Converts `building-on` in `contrib/guix/toolchains.scm` from an eagerly evaluated variable into a procedure evaluated when lowering derivations. This ensures cross-toolchain packages use the target system passed via Guix's `--system` flag rather than the host system running `guix shell`.", "problem": "When running Guix with `--system` under emulation on a host of a different architecture (for example, `--system=aarch64-linux` on an x86_64 host), `guix shell` loads manifests before applying `--system`. As a result, `building-on` captures the host's `%current-system`, causing cross toolchains like `gcc-cross-sans-libc` to configure with mismatched `--build` triplets and fail to build.", "card": "Converts the `building-on` triplet resolution in `contrib/guix/toolchains.scm` from an eagerly evaluated variable into a procedure evaluated when lowering derivations. When running Guix with `--system` on a foreign host via emulation (such as building for aarch64 on x86_64), manifests previously evaluated `%current-system` at module load time, generating an incorrect `--build` triplet that broke cross-toolchain configuration for `gcc-cross-sans-libc`. The change fixes emulated cross-system Guix builds without modifying the derivations produced for native release builds.", "evidence": [ "PR description demonstrates build failure: 'checking for CET support... configure: error: compiler and assembler with CET support are required for --enable-cet' when building under `--system=aarch64-linux` on x86_64", "PR description confirms native builds produce identical toolchain derivations to master on both `linux_static.scm` and `manifest_gui.scm`" ], "scope_notes": "", "changed_since_previous": "No functional changes; the previous description was generated before the patch was available.", "thread": { "last_event_at": "2026-10-30T15:38:55Z", "events": 3, "head_sha": "1ea9ffd556e5d9576b5226239e0eceacb516bc82", "schema_floor": 2, "schema": 2 }, "waiting_on": [ { "at": "2026-10-30", "id": "c:6526771255", "on": "reviewer", "url": "https://github.com/bitcoin/bitcoin/pull/36709#issuecomment-6526771255", "what": "further review after author answered sedited's question" }, { "at": "2026-10-30", "id": "c:6526771255", "on": "reviewer", "url": "https://github.com/bitcoin/bitcoin/pull/36709#issuecomment-6526771255", "what": "code review following author reply and Concept ACK" } ], "risk": { "level": "medium", "touches": [ "build" ], "why": "A mistake in Guix toolchain definitions could alter compiler build flags or break reproducible release builds across supported architectures." }, "discussion": { "author_status": "last statement processed 2026-10-30", "open_concerns": [], "resolved_concerns": [ "sedited: How and why did the author run into this issue? (answered by jespada 2026-10-30)" ] }, "reviewability": { "state": "Ready", "label": "Ready", "reason": "Nothing known that would invalidate a review now." }, "agreement": { "state": "Positive", "summary": "Positive: support without stated reasons, no open objection (hebasto)", "reason": "Initial record. hebasto offered a Concept ACK, and sedited asked about the author's motivation and setup, which jespada answered. / Initial record. sedited asked why the author ran into this, which was answered; hebasto left a Concept ACK.", "evidence": [ "hebasto: Concept ACK \u2014 Concept ACK." ], "objections": [ { "reviewer": "sedited", "association": "MEMBER", "type": "question", "kind": "usefulness", "harm": "", "request": "", "question": "How and why did the author run into this issue?", "text": "How and why did the author run into this issue?", "clears_with": "answer", "blocking": false, "status": "answered", "status_note": "author explained they encountered it while testing build reproducibility across architectures under QEMU emulation", "cleared": true, "author_replied": true, "others_replied": false, "fix_pushed": false, "replies": [ "c:6526771255" ], "evidence": "2026-10-30: 'How and why did you run into this?'", "url": "https://github.com/bitcoin/bitcoin/pull/36709#issuecomment-6526424366", "id": "c:6526424366", "at": "2026-10-30", "status_at": "2026-10-30", "status_by": "jespada", "resolution_evidence": "2026-10-30: jespada: 'I hit it while trying to build https://github.com/bitcoin/bitcoin/pull/36708 with an aarch64 build machine'", "pin": null, "from_schema": 2 } ], "support": [ { "reviewer": "hebasto", "reason": "Concept ACK.", "substantive": false, "verdict": "Concept ACK", "id": "r:5714645723", "url": "https://github.com/bitcoin/bitcoin/pull/36709#pullrequestreview-5714645723", "at": "2026-10-30", "association": "MEMBER", "evidence": "none", "areas": [] } ], "participants": [ { "login": "hebasto", "stance": "support", "note": "Concept ACK", "association": "MEMBER", "comments": 1, "first": "2026-10-30", "last": "2026-10-30" }, { "login": "sedited", "stance": "question", "note": "asked how and why the author ran into the issue", "association": "MEMBER", "comments": 1, "first": "2026-10-30", "last": "2026-10-30" } ], "derivation": "support without stated reasons, no open objection (hebasto)", "model_state": null, "corrections": [], "notes": "Initial record. hebasto offered a Concept ACK, and sedited asked about the author's motivation and setup, which jespada answered. / Initial record. sedited asked why the author ran into this, which was answered; hebasto left a Concept ACK." }, "dependencies": { "depends_on": [], "enables": [] }, "categories": [ { "name": "build", "member": true, "evidence": "Matches 'Build system' label and edits 'contrib/guix/toolchains.scm', which configures Guix cross-toolchain packages.", "band": "P3", "reason_tag": "platform fix", "score": 0.35, "factors": { "bug_severity": 1, "leverage": 1, "performance": 0, "security_stability": 0, "user_value": 0 }, "rationale": "Fixes a Guix build failure when running under foreign architecture emulation with `--system`. Guix shell currently captures the host `%current-system` at load time before applying `--system`, causing cross toolchains like `gcc-cross-sans-libc` to fail configuration due to mismatched triplets." }, { "name": "tools", "member": false, "evidence": "Category definition explicitly specifies that 'Build and release scripts are build'.", "band": "Unranked", "reason_tag": "cleanup", "score": 0.0, "factors": { "bug_severity": 1, "leverage": 1, "performance": 0, "security_stability": 0, "user_value": 0 }, "rationale": "Files under contrib/guix/ belong to the build system category rather than general tools and scripts." } ], "confidence": "high", "uncertainties": [], "needs": [] }, "cost_usd": 0.0, "source": { "record": "2026-11-01T01:16:00+00:00", "code": "2026-11-01T01:20:18+00:00", "judgments": 2 } }