Fix build script to work correctly on clean checkout

This means we need to run the script much less often.

build

@@ -2,5 +2,9 @@
 set -euo pipefail
 
 cargo build --manifest-path ./rust/Cargo.toml
-ln -sf $(pwd)/rust/target/debug/libgarnet_rs.a $(cabal list-bin . | sed -e 's=x/garnet/build/garnet/garnet=build=g')
+
+BUNDLED_LIB_DIR=$(cabal list-bin . | sed -e 's=x/garnet/build/garnet/garnet=build=g')
+mkdir -p $BUNDLED_LIB_DIR
+ln -sf $(pwd)/rust/target/debug/libgarnet_rs.a $BUNDLED_LIB_DIR
+
 cabal build

cabal.project

@@ -6,9 +6,9 @@ packages: .
 source-repository-package
   type: git
   location: https://github.com/well-typed/hs-bindgen
-  tag: 94d74d3f3e72c8fabc85700f916387fe851ba20a
+  tag: 6ca94188abd756a1fb4dd8a4037de3fa7dca0765
   subdir: c-expr-dsl c-expr-runtime hs-bindgen hs-bindgen-runtime
-  --sha256: eM0CJj1HDAClvjkv5QUaF7aZoMwnPm4GuoLTkp8SHq8=
+  --sha256: M+8tEZA8gsEc6gXnNdSbRpMBQ5LkH7sphcV1aR0fclA=
 source-repository-package
   type: git
   location: https://github.com/well-typed/libclang

lib/GarnetRs/Raw.hs

@@ -15,6 +15,7 @@ module GarnetRs.Raw where
 -- {-# LANGUAGE ExplicitLevelImports #-}
 -- import HsBindgen.Runtime.LibC qualified
 -- import splice Data.List
+-- import splice Data.Text qualified as T
 -- import splice Data.Tuple.Extra
 -- import splice HsBindgen.TH
 -- import splice Language.Haskell.TH

lib/GarnetRs/Wrapped.hs

@@ -34,8 +34,8 @@ data Shape
     | Rectangle CDouble CDouble
 convertShape :: Shape -> Raw.Shape
 convertShape = \case
-    Circle r -> Raw.Shape Raw.Circle $ Raw.set_shape_anon0_circle $ Raw.Circle_Body r
-    Rectangle w h -> Raw.Shape Raw.Rectangle $ Raw.set_shape_anon0_rectangle $ Raw.Rectangle_Body w h
+    Circle r -> Raw.Shape Raw.Circle $ Raw.set_shape_body_circle $ Raw.Circle_Body r
+    Rectangle w h -> Raw.Shape Raw.Rectangle $ Raw.set_shape_body_rectangle $ Raw.Rectangle_Body w h
 
 data BTree a
     = Leaf a
@@ -43,14 +43,14 @@ data BTree a
 withBTree :: BTree Int64 -> (Raw.BTreeC -> IO a) -> IO a
 withBTree =
     runContT . fix \f -> \case
-        Leaf v -> pure $ Raw.BTreeC Raw.Leaf $ Raw.set_bTreeC_anon0_leaf $ Raw.Leaf_Body v
+        Leaf v -> pure $ Raw.BTreeC Raw.Leaf $ Raw.set_bTreeC_body_leaf $ Raw.Leaf_Body v
         Fork l r -> do
             lRaw <- f l
             rRaw <- f r
             lPtr <- ContT alloca
             rPtr <- ContT alloca
             lift $ poke lPtr lRaw >> poke rPtr rRaw
-            pure . Raw.BTreeC Raw.Fork . Raw.set_bTreeC_anon0_fork $
+            pure . Raw.BTreeC Raw.Fork . Raw.set_bTreeC_body_fork $
                 Raw.Fork_Body (unsafeFromPtr lPtr) (unsafeFromPtr rPtr)
 
 hello :: ByteString -> IO ()

rust/build.rs

@@ -1,19 +1,43 @@
 use std::env;
+use std::fs;
 use std::path::PathBuf;
 
 fn main() {
     let crate_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
     let profile = env::var("PROFILE").unwrap();
-    cbindgen::Builder::new()
+
+    let bindings = cbindgen::Builder::new()
         .with_crate(&crate_dir)
         .with_language(cbindgen::Language::C)
         .with_style(cbindgen::Style::Tag)
         .generate()
-        .expect("Unable to generate bindings")
-        .write_to_file(
+        .expect("Unable to generate bindings");
+
+    // TODO vibe-coded workaround for hs-bindgen issue:
+    // https://github.com/well-typed/hs-bindgen/issues/1649#issuecomment-3994425922
+    let mut buf = Vec::new();
+    bindings.write(&mut buf);
+    let header = String::from_utf8(buf).unwrap();
+    let mut patched = String::new();
+    let mut saw_union = false;
+    for line in header.lines() {
+        if line == "  };" && saw_union {
+            patched.push_str("  } body;\n");
+            saw_union = false;
+            continue;
+        }
+        if line == "  union {" {
+            saw_union = true;
+        }
+        patched.push_str(line);
+        patched.push('\n');
+    }
+    fs::write(
         PathBuf::from(&crate_dir)
             .join("target")
             .join(&profile)
             .join("garnet_rs.h"),
-        );
+        patched,
+    )
+    .unwrap();
 }