kernel-cases: an smlib feature for the CLI, and no grading of a kernel the build isn't running

- solidcraft-cli and solidcraft-engine forward an `smlib` feature to solidcraft-kernel/smlib, so
  `cargo build -p solidcraft-cli --features smlib` gives the rig SMLib's check.
- solidcraft_kernel::boolean_kernel() says which kernel this process runs booleans on.
  `default` until the SMLib switch (SOLIDCRAFT_BOOLEANS=smlib) lands and answers there. An smlib
  run on a build without the switch reports "not supported yet" instead of grading the default
  kernel under SMLib's name.
- An area may keep its skipped list in parts (skipped-<part>.json).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/solidcraft-cli/Cargo.toml

@@ -24,6 +24,10 @@ default = ["raytrace-cpu"]
 bundled-render-library = ["solidcraft-engine/bundled-render-library"]
 raytrace-cpu = ["solidcraft-engine/raytrace-cpu"]
 
+[features]
+# Link SMLib into the kernel, for the regression rig's smlib runs (tests/kernel-cases).
+smlib = ["solidcraft-engine/smlib"]
+
 [dependencies]
 solidcraft-engine = { workspace = true }
 solidcraft-gpu = { workspace = true }

apps/solidcraft-cli/src/kernel_cases.rs

@@ -62,7 +62,13 @@ fn check_case(dir: &str) -> Value {
     };
     if kernel() == "smlib" && !solidcraft_engine::kernel::smlib_built() {
         out["status"] = json!("unsupported");
-        out["error"] = json!("this build has no SMLib: build solidcraft-cli with --features solidcraft-kernel/smlib");
+        out["error"] = json!("this build has no SMLib: build solidcraft-cli with --features smlib");
+        return out;
+    }
+    let running = solidcraft_engine::kernel::boolean_kernel();
+    if kernel() != running {
+        out["status"] = json!("unsupported");
+        out["error"] = json!(format!("this build runs booleans on the {running} kernel, not {}", kernel()));
         return out;
     }
     let refused = want["outcome"].as_str() == Some("refused");

crates/engine/Cargo.toml

@@ -13,6 +13,8 @@ default = []
 # Optional authored texture/HDR bytes; the command registry and metadata remain available.
 bundled-render-library = []
 raytrace-cpu = ["solidcraft-render/raytrace-cpu"]
+# Link SMLib into the kernel (solidcraft-kernel/smlib; needs scripts/fetch-smlib.sh).
+smlib = ["solidcraft-kernel/smlib"]
 # Turns on the parameter-contract audit recorder (`SOLIDCRAFT_PARAM_AUDIT`, see
 # `src/schema/record.rs`), for checking a new contract against the whole test suite.
 param-audit = []

crates/kernel/src/lib.rs

@@ -224,7 +224,7 @@ pub use sweep_path::{RailFit, SweepControl, SweepOrientation, sweep_path, sweep_
 pub use topo::{CylinderFace, cylinder_end_at, cylinder_face, cylinder_face_at};
 pub use topo::{TopoCounts, merged_topology, seam_flags};
 pub use tspline::tspline_sheet;
-pub use validity::{Validity, smlib_built, validity};
+pub use validity::{Validity, boolean_kernel, smlib_built, validity};
 pub use whole_face::{WholeFace, cut_takes_only_the_face, cut_tool, face_prism, matching_face};
 
 #[derive(Debug, Clone, PartialEq, thiserror::Error)]

crates/kernel/src/validity.rs

@@ -47,3 +47,11 @@ fn smlib_validity(_: &Body) -> Option<Result<(), String>> {
 pub fn smlib_built() -> bool {
     cfg!(feature = "smlib")
 }
+
+/// The kernel booleans run on in this process: `"default"` or `"smlib"`. The regression rig
+/// refuses to grade a kernel the process isn't running. The SMLib boolean switch
+/// (`SOLIDCRAFT_BOOLEANS=smlib`) answers here once it lands; until then this is always
+/// `"default"`.
+pub fn boolean_kernel() -> &'static str {
+    "default"
+}

tests/kernel-cases/README.md

@@ -10,7 +10,7 @@ cargo xtask kernel-cases --kernel both --cli target/release/solidcraft-cli   # a
 cargo run -p solidcraft-cli -- kernel-cases tests/kernel-cases/booleans/<id>     # one case
 ```
 
-For the `smlib` column, build `solidcraft-cli` with `--features solidcraft-kernel/smlib` (after
+For the `smlib` column, build `solidcraft-cli` with `--features smlib` (after
 `scripts/fetch-smlib.sh`). The rig sets `SOLIDCRAFT_BOOLEANS=smlib` for those runs.
 
 ## Rules
@@ -46,8 +46,8 @@ Each case has:
   specification, never a user's file).
 - `expected.json`: the right answer, graded by `solidcraft-cli kernel-cases`.
 
-Each area also has `skipped.json`: every issue and PR looked at that did not become a case, with
-one line each saying why.
+Each area also has `skipped.json` (or several, `skipped-<part>.json`, where an area is triaged in
+parts): every issue and PR looked at that did not become a case, with one line each saying why.
 
 ```json
 [{"source": "tangency-labs/solidcraft#123", "why": "UI only: the selection highlight, no geometry"}]

xtask/src/kernel_cases.rs

@@ -189,6 +189,11 @@ fn sources_of(want: &Value) -> Vec<String> {
     want["sources"].as_array().into_iter().flatten().filter_map(|s| s.as_str().map(str::to_string)).collect()
 }
 
+/// The number in `owner/repo#123`, for sorting.
+fn source_number(s: &str) -> u64 {
+    s.rsplit('#').next().and_then(|n| n.parse().ok()).unwrap_or(u64::MAX)
+}
+
 /// `tangency-labs/solidcraft#123` as a link.
 fn link(source: &str) -> String {
     match source.split_once('#') {
@@ -274,8 +279,20 @@ fn write_report(o: &Options, dir: &Path, list: &[PathBuf], results: &[Value]) ->
     let mut area_dirs: Vec<PathBuf> = std::fs::read_dir(dir).map_err(|e| e.to_string())?.flatten().map(|e| e.path()).filter(|p| p.is_dir()).collect();
     area_dirs.sort();
     for a in area_dirs {
-        let list = read(&a.join("skipped.json"));
-        let Some(items) = list.as_array().filter(|l| !l.is_empty()) else { continue };
+        // skipped.json, or several (skipped-<part>.json) where people triage an area in parts.
+        let mut files: Vec<PathBuf> = std::fs::read_dir(&a)
+            .map_err(|e| e.to_string())?
+            .flatten()
+            .map(|e| e.path())
+            .filter(|p| p.file_name().and_then(|n| n.to_str()).is_some_and(|n| n.starts_with("skipped") && n.ends_with(".json")))
+            .collect();
+        files.sort();
+        let mut items: Vec<Value> = files.iter().flat_map(|f| read(f).as_array().cloned().unwrap_or_default()).collect();
+        if items.is_empty() {
+            continue;
+        }
+        items.sort_by_key(|it| source_number(it["source"].as_str().unwrap_or("")));
+        let items = &items;
         md += &format!("### {}\n\n| Source | Why skipped |\n|---|---|\n", a.file_name().map(|n| n.to_string_lossy().to_string()).unwrap_or_default());
         for it in items {
             skipped += 1;