build: dual-output generated tests (tests/generated local, OUT_DIR CI/publish)

build.rs generates per-case test .rs into tests/generated for local builds (compiled via mod generated) and into OUT_DIR/generated for CI (CI=true) and publish verify (target/package), switched via cargo:rustc-cfg=use_out_dir. Cargo.toml excludes tests/ from the published package; build.rs early-returns when tests/cases is absent (published crate or dependent build), so it never writes outside OUT_DIR and never pollutes the registry source dir. cargo package verify passes.

Author: TtTRz

float-pigment-forest/Cargo.toml

@@ -10,6 +10,7 @@ keywords.workspace = true
 license.workspace = true
 repository.workspace = true
 build = "build.rs"
+exclude = ["tests"]
 
 [lib]
 name = "float_pigment_forest"

float-pigment-forest/build.rs

@@ -3,21 +3,18 @@
 // (create_node / create_text / set_style / append + layout_imperative +
 // getters).
 //
-// Output (per-case .rs under <gen_dir>/<topic>/<case>.rs, not one big file):
-//   - OUT_DIR/generated/<topic>/<case>.rs + OUT_DIR/generated/all.rs
-//     (all.rs does `include!("topic/case.rs")` for each case — paths resolve
-//     relative to all.rs, which lives next to the <topic>/ dirs). tests/mod.rs
-//     pulls all.rs in via `include!(OUT_DIR/generated/all.rs)`. This is what
-//     compiles.
-//   - Local (non-CI, non-publish-verify) builds ALSO write the same tree
-//     under tests/generated/ for human review. CI (CI=true) and cargo
-//     package/publish verify (CARGO_MANIFEST_DIR under target/package) skip
-//     the tests/generated mirror — CI doesn't need it, and publish verify
-//     forbids build.rs from writing outside OUT_DIR.
+// Output location depends on context:
+//   - Local builds (no CI env, not under target/package): writes
+//     tests/generated/<topic>/<case>.rs + nested mod tree, compiled by
+//     tests/mod.rs via `mod generated;`. Source tree, human-readable.
+//   - CI (CI=true) and cargo package/publish verify (CARGO_MANIFEST_DIR
+//     under target/package): writes OUT_DIR/generated/<topic>/<case>.rs +
+//     all.rs (which include!s each case), compiled by tests/mod.rs via
+//     `include!(OUT_DIR/generated/all.rs)`. Keeps the source tree untouched
+//     (publish verify forbids build.rs from writing outside OUT_DIR).
 //
-// Each per-case .rs puts `use crate::TestCtx;` *inside* the fn so that
-// all.rs's flat include! sequence doesn't trip "duplicate use" — each fn
-// brings TestCtx into its own scope.
+// build.rs emits `cargo:rustc-cfg=use_out_dir` in the OUT_DIR branch so
+// tests/mod.rs can switch between the two with #[cfg(use_out_dir)].
 //
 // The translator walks the parsed DOM and emits imperative calls in
 // document order. Layout assertions (data-expect-*) are collected during
@@ -37,8 +34,16 @@ use float_pigment_mlp::{
 fn main() {
     let manifest = std::env::var("CARGO_MANIFEST_DIR").unwrap();
     let cases_dir = PathBuf::from(&manifest).join("tests/cases");
-    let out = std::env::var("OUT_DIR").unwrap();
-    let out_gen = PathBuf::from(&out).join("generated");
+    // Published crate excludes tests/ (Cargo.toml `exclude`), so there are no
+    // cases to translate — and we must not write anything: build.rs also runs
+    // when a dependent crate builds us (in the registry source dir), which
+    // must stay clean.
+    if !cases_dir.exists() {
+        return;
+    }
+    let is_ci = std::env::var("CI").is_ok();
+    let is_publish_verify = manifest.contains("target/package");
+    let use_out_dir = is_ci || is_publish_verify;
 
     // topic -> Vec<(case_name, name_ident, body, ignore)>
     let mut by_topic: BTreeMap<String, Vec<(String, String, String, bool)>> = BTreeMap::new();
@@ -65,58 +70,77 @@ fn main() {
         }
     }
 
-    // OUT_DIR/generated: per-case .rs + all.rs (compiled). all.rs is always
-    // emitted here; mod.rs/ tree is also emitted (harmless, aids browsing).
-    write_cases_tree(&out_gen, &by_topic, true);
-
-    // Local mirror under tests/generated for human review.
-    let is_ci = std::env::var("CI").is_ok();
-    let is_publish_verify = manifest.contains("target/package");
-    if !is_ci && !is_publish_verify {
+    if use_out_dir {
+        let out = std::env::var("OUT_DIR").unwrap();
+        let out_gen = PathBuf::from(&out).join("generated");
+        write_out_dir_tree(&out_gen, &by_topic);
+        // Switch tests/mod.rs to include!(OUT_DIR/generated/all.rs).
+        println!("cargo:rustc-cfg=use_out_dir");
+    } else {
         let gen_dir = PathBuf::from(&manifest).join("tests/generated");
-        write_cases_tree(&gen_dir, &by_topic, false);
+        write_source_tree(&gen_dir, &by_topic);
     }
 
     println!("cargo:rerun-if-changed=tests/cases");
     println!("cargo:rerun-if-changed=build.rs");
 }
 
-/// Write per-case .rs under `<gen_dir>/<topic>/<case>.rs` plus a nested
-/// `mod.rs` tree (browsing aid) and, when `emit_all_rs`, an `all.rs` that
-/// `include!`s every case — that all.rs is what tests/mod.rs compiles.
-fn write_cases_tree(
+/// OUT_DIR branch: per-case .rs + all.rs. all.rs does
+/// `include!("topic/case.rs")` for each case (paths resolve relative to
+/// all.rs). tests/mod.rs include!s all.rs. Each fn has `use crate::TestCtx`
+/// inside the body so all.rs's flat include! does not duplicate the use.
+fn write_out_dir_tree(
     gen_dir: &Path,
     by_topic: &BTreeMap<String, Vec<(String, String, String, bool)>>,
-    emit_all_rs: bool,
 ) {
     let _ = fs::remove_dir_all(gen_dir);
     fs::create_dir_all(gen_dir).unwrap();
     let mut all_rs = String::from("// AUTO-GENERATED by build.rs. Do not edit.\n\n");
-    let mut top_mod = String::from("// AUTO-GENERATED by build.rs. Do not edit.\n\n");
     for (topic, cases) in by_topic {
         let topic_dir = gen_dir.join(topic);
         fs::create_dir_all(&topic_dir).unwrap();
         let topic_ident = topic.replace('-', "_");
-        let mut topic_mod = String::from("// AUTO-GENERATED. Do not edit.\n\n");
         for (name, name_ident, body, ignore) in cases {
             let fn_name = format!("html_{}_{}", topic_ident, name_ident);
             let ignore_attr = if *ignore { "#[ignore]\n" } else { "" };
             let case_rs = format!(
                 "// AUTO-GENERATED from tests/cases/{topic}/{name}.html. Do not edit.\n\n{ignore_attr}#[rustfmt::skip]\n#[test]\nfn {fn_name}() {{\n    use crate::TestCtx;\n{body}}}\n"
             );
             fs::write(topic_dir.join(format!("{name}.rs")), &case_rs).unwrap();
-            // all.rs includes each case; path is relative to all.rs (gen_dir),
-            // which sits next to <topic>/, so "<topic>/<case>.rs" resolves.
             all_rs.push_str(&format!("include!(\"{topic}/{name}.rs\");\n"));
+        }
+    }
+    fs::write(gen_dir.join("all.rs"), all_rs).unwrap();
+}
+
+/// Source-tree branch: per-case .rs + nested mod.rs tree under tests/generated.
+/// tests/mod.rs compiles it via `mod generated;`. Each case is its own mod,
+/// so file-level `use crate::TestCtx;` is fine.
+fn write_source_tree(
+    gen_dir: &Path,
+    by_topic: &BTreeMap<String, Vec<(String, String, String, bool)>>,
+) {
+    let _ = fs::remove_dir_all(gen_dir);
+    fs::create_dir_all(gen_dir).unwrap();
+    let mut top_mod = String::from("// AUTO-GENERATED by build.rs. Do not edit.\n\n");
+    for (topic, cases) in by_topic {
+        let topic_dir = gen_dir.join(topic);
+        fs::create_dir_all(&topic_dir).unwrap();
+        let topic_ident = topic.replace('-', "_");
+        let mut topic_mod = String::from("// AUTO-GENERATED. Do not edit.\n\n");
+        for (name, name_ident, body, ignore) in cases {
+            let fn_name = format!("html_{}_{}", topic_ident, name_ident);
+            let ignore_attr = if *ignore { "#[ignore]\n" } else { "" };
+            let case_rs = format!(
+                "// AUTO-GENERATED from tests/cases/{topic}/{name}.html. Do not edit.\nuse crate::TestCtx;\n\n{ignore_attr}#[rustfmt::skip]\n#[test]\nfn {fn_name}() {{\n{body}}}\n"
+            );
+            fs::write(topic_dir.join(format!("{name}.rs")), &case_rs).unwrap();
             topic_mod.push_str(&format!("mod {name_ident};\n"));
         }
         fs::write(topic_dir.join("mod.rs"), topic_mod).unwrap();
         top_mod.push_str(&format!("mod {topic_ident};\n"));
     }
-    fs::write(gen_dir.join("mod.rs"), top_mod).unwrap();
-    if emit_all_rs {
-        fs::write(gen_dir.join("all.rs"), all_rs).unwrap();
-    }
+    fs::write(gen_dir.join("mod.rs"), top_mod).unwrap()
 }
 
 /// Parse the HTML and emit imperative TestCtx calls.

float-pigment-forest/tests/mod.rs

@@ -677,4 +677,7 @@ fn convert_grid_auto(grid_auto: GridAuto) -> LayoutGridAuto<Len> {
     }
 }
 
+#[cfg(use_out_dir)]
 include!(concat!(env!("OUT_DIR"), "/generated/all.rs"));
+#[cfg(not(use_out_dir))]
+mod generated;