ci: fingerprint Cargo.toml's profile tables, not the whole manifest (#7282)

benchmarks/public_baseline.py

@@ -130,10 +130,46 @@ def _is_resolved_path(value: Any) -> bool:
     return bool(text) and (os.path.isabs(text) or os.sep in text)
 
 
+def _cargo_profile_tables(data: bytes) -> bytes:
+    """The `[profile.*]` tables of a Cargo manifest, and nothing else.
+
+    #7282: `Cargo.toml` was fingerprinted whole-file (modulo the version line,
+    which #7264's normalization already neutralized). Everything else in it —
+    a new `perry-ext-*` workspace member, a dependency bump, a `[workspace]`
+    restructure — invalidated the published baseline without being able to
+    change a measured number. #6758/#6761's restructuring tripped it with the
+    `.ts` kernels untouched, and the artifact then sat 40+ commits stale on a
+    REQUIRED check, so every later `lint` step never ran at all and every merge
+    needed an `--admin` bypass.
+
+    What genuinely can move a number is the build profile: `opt-level`, `lto`,
+    `codegen-units`, `panic`. So only those tables participate.
+
+    Extraction is deliberately textual and conservative — a TOML parser is not
+    guaranteed available in the CI Python, and this must agree byte-for-byte
+    between the generator and the checker. A section header ends the capture
+    unless it is itself a `[profile...` header, so `[profile.release.package.x]`
+    subtables are kept.
+    """
+    kept: list[bytes] = []
+    capturing = False
+    for line in data.splitlines(keepends=True):
+        stripped = line.strip()
+        if stripped.startswith(b"[") and stripped.endswith(b"]"):
+            capturing = stripped.startswith(b"[profile")
+        if capturing:
+            kept.append(line)
+    return b"".join(kept)
+
+
 def _fingerprint_bytes(name: str) -> bytes:
     data = (ROOT / name).read_bytes()
     if name == "Cargo.toml":
+        # The version normalization stays: `[workspace.package] version` is not
+        # in a profile table, but keeping the substitution makes the intent
+        # explicit if the extraction below is ever widened.
         data = _CARGO_VERSION_RE.sub(b'version = "0.0.0"', data)
+        data = _cargo_profile_tables(data)
     return data
 
 

benchmarks/results/public-node-bun-v1.json

@@ -5,8 +5,8 @@
   "perry_version": "perry 0.5.1355",
   "generated_at": "2026-08-08T11:42:16Z",
   "freshness": {
-    "source_fingerprint": "57fe15fcce9a80de22d56d4075cb4cc196a8246ff2920f61ff8a0a11299d9ddf",
-    "harness_fingerprint": "45ac06e91e37d0873f543d02d6f1d1af9470d014c0dd7fa01a1e22b57707adb9"
+    "source_fingerprint": "65a1218e02c95b4aa8ed22065ca33e4653addcd81a77a4fb1a810e5153e07887",
+    "harness_fingerprint": "28117b86b2bcca9cc4e6f418f156bfcce0b4bf0851698c3e88525737221df49b"
   },
   "host": {
     "os_version": "26.5.1",

changelog.d/7821-narrow-baseline-fingerprint.md

@@ -0,0 +1,22 @@
+**The public-baseline freshness gate no longer fires on `Cargo.toml` changes that cannot move a measured number** (#7282, proposal 1 — the issue's "single biggest win").
+
+`Cargo.toml` was fingerprinted whole-file. A new `perry-ext-*` workspace member, a dependency bump or a `[workspace]` restructure invalidated the published artifact without touching a benchmarked kernel — #6758/#6761's restructuring did exactly that, and the artifact then sat **40+ commits stale on a REQUIRED check**, so every later `lint` step (file-size, GC store-site inventory, addr-class audit, #7253's gate-wiring check) never executed in CI at all, and every merge needed an `--admin` bypass.
+
+Only the `[profile.*]` tables now participate — `opt-level`, `lto`, `codegen-units`, `panic`, i.e. the things that genuinely change comparability. Extraction is textual and conservative (no TOML parser is guaranteed in the CI Python, and generator and checker must agree byte-for-byte); a section header ends the capture unless it is itself `[profile…`, so `[profile.release.package.x]` subtables are kept. Measured: 19,466 bytes → 8,681, all 45 profile tables retained, `[workspace.package]` and every dependency line gone.
+
+**Sabotage-verified in both directions**, by exit code rather than by message:
+
+| planted change | `ci_public_baseline_check.py` |
+|---|--:|
+| `[profile.release] opt-level = 3 → 2` | **exit 2** — "benchmark inputs changed; regenerate it" |
+| new `crates/perry-ext-sabotage` workspace member | **exit 0** |
+
+So the gate keeps blocking absolutely on what matters and stops firing on what does not — the issue's explicit requirement that it stay required and hard-failing.
+
+**On the artifact's stored digests.** Narrowing the fingerprint changes both keys, so they are recomputed in the same commit. That is sound rather than an attestation: the artifact **matches under the broad fingerprint today** (verified before the change), and the narrow fingerprint covers a strict subset of those inputs — an artifact valid under the broad one is necessarily valid under the narrower one. No measurement was re-run and none needed to be: everything in the file except the two `freshness` digests is byte-identical, asserted programmatically. Independently, the `[profile.*]` extract is unchanged from the artifact's own commit (`38ff7eccc`) through HEAD, and across `HEAD~40` and `HEAD~120`.
+
+Also worth recording: the issue's headline complaint — "`Cargo.toml` changes on every version bump" — was **already fixed** before this change. `_fingerprint_bytes` normalizes the `version = "…"` line to `0.0.0`, which is why the gate was green today despite `0.5.1355 → 0.5.1461`. This change addresses what was left.
+
+Scope is proposal 1 only. `HARNESS_PATHS` still fingerprints scripts whose error handling cannot change a number (#7265's `run.sh` fix is the cited example); proposal 2's measurement-affecting/plumbing split is untouched. The deliberate circularity is preserved — `ci_public_baseline_check.py` stays out of `public_baseline.py` so the checker's own file is not in `HARNESS_PATHS`.
+
+Verified: `tests/test_public_baseline.py` 7 passed, `benchmarks/ci_public_baseline_check.py` exit 0, file-size gate clean.