Fix Koharu enum ABI in release builds

Author: fffonion

.github/scripts/patch-koharu-diffusion.py

@@ -0,0 +1,82 @@
+"""Patch koharu-diffusion's C enum wrappers for the current target ABI."""
+
+from __future__ import annotations
+
+import json
+import subprocess
+from pathlib import Path
+
+
+def koharu_enums_path() -> Path:
+    metadata = subprocess.run(
+        ["cargo", "metadata", "--locked", "--format-version", "1"],
+        check=True,
+        stdout=subprocess.PIPE,
+        text=True,
+        encoding="utf-8",
+    )
+    packages = json.loads(metadata.stdout)["packages"]
+    matches = [
+        package
+        for package in packages
+        if package["name"] == "koharu-diffusion"
+        and package["source"].startswith("git+")
+    ]
+    if len(matches) != 1:
+        raise RuntimeError(
+            f"expected one Git koharu-diffusion package, found {len(matches)}"
+        )
+    return Path(matches[0]["manifest_path"]).parent / "src" / "enums.rs"
+
+
+path = koharu_enums_path()
+source = path.read_text(encoding="utf-8")
+
+if "type FfiEnumRepr" not in source:
+    anchor = "use crate::{Error, Result, ffi::NativeCall, sys};\n"
+    replacement = anchor + """
+
+// Clang uses an unsigned C enum representation for these non-negative values,
+// while MSVC uses a signed representation. Match bindgen's target ABI.
+#[cfg(target_env = "msvc")]
+type FfiEnumRepr = i32;
+#[cfg(not(target_env = "msvc"))]
+type FfiEnumRepr = u32;
+"""
+    if source.count(anchor) != 1:
+        raise RuntimeError("koharu-diffusion import anchor changed")
+    source = source.replace(anchor, replacement)
+
+replacements = {
+    "        #[repr(i32)]\n": (
+        "        #[cfg_attr(target_env = \"msvc\", repr(i32))]\n"
+        "        #[cfg_attr(not(target_env = \"msvc\"), repr(u32))]\n"
+    ),
+    "pub const fn as_raw(self) -> i32": "pub const fn as_raw(self) -> FfiEnumRepr",
+    "impl TryFrom<i32> for $name": "impl TryFrom<FfiEnumRepr> for $name",
+    "fn try_from(value: i32) -> Result<Self>": (
+        "fn try_from(value: FfiEnumRepr) -> Result<Self>"
+    ),
+    "value => Err(Error::InvalidEnum { kind: $kind, value }),": (
+        "value => Err(Error::InvalidEnum { kind: $kind, value: value as i32 }),"
+    ),
+}
+
+expected_counts = {
+    "        #[repr(i32)]\n": 2,
+    "pub const fn as_raw(self) -> i32": 2,
+    "impl TryFrom<i32> for $name": 2,
+    "fn try_from(value: i32) -> Result<Self>": 2,
+    "value => Err(Error::InvalidEnum { kind: $kind, value }),": 2,
+}
+
+for old, new in replacements.items():
+    count = source.count(old)
+    if count == 0 and new in source:
+        continue
+    if count != expected_counts[old]:
+        raise RuntimeError(f"unexpected occurrence count for {old!r}: {count}")
+    source = source.replace(old, new)
+
+path.write_text(source, encoding="utf-8")
+print(f"patched {path}")

.github/workflows/release.yml

@@ -55,6 +55,10 @@ jobs:
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@stable
 
+      - name: Patch Koharu C enum ABI compatibility
+        working-directory: flint
+        run: python .github/scripts/patch-koharu-diffusion.py
+
       - name: Preload Unix LibTorch
         if: runner.os != 'Windows'
         working-directory: flint