fix: statically link Windows native CRT

Author: RtlZeroMemory

.github/workflows/prebuild.yml

@@ -71,6 +71,8 @@ jobs:
           arch: ${{ matrix.msvcArch }}
 
       - name: Build prebuild
+        env:
+          RUSTFLAGS: ${{ runner.os == 'Windows' && '-C target-feature=+crt-static' || '' }}
         run: npx napi build --platform --release --target "${{ matrix.rustTarget }}" --js false
         working-directory: packages/native
 

.github/workflows/release.yml

@@ -332,6 +332,8 @@ jobs:
           arch: ${{ matrix.msvcArch }}
 
       - name: Build prebuild
+        env:
+          RUSTFLAGS: ${{ runner.os == 'Windows' && '-C target-feature=+crt-static' || '' }}
         run: npx napi build --platform --release --target "${{ matrix.rustTarget }}" --js false
         working-directory: packages/native
 

CHANGELOG.md

@@ -14,6 +14,9 @@ The format is based on Keep a Changelog and the project follows Semantic Version
 
 ### Fixed
 
+- **native/windows**: Windows prebuilt native binaries now link the MSVC runtime
+  statically, so packaged apps can run on clean Windows installs without a
+  separate Visual C++ Redistributable install.
 - **core/renderer**: Per-side box borders now render standalone edges. A box with only `borderLeft` (or any vertical-only side combination) previously drew nothing when shorter than 2 rows; corner rows are now only required when a horizontal edge is present. Markdown blockquotes use this to render a GitHub-style dim left bar instead of a rounded box.
 
 ## [0.1.0-beta.3] - 2026-06-11

docs/backend/native.md

@@ -37,6 +37,8 @@ combinations:
 When you install `@rezi-ui/native`, the correct prebuilt binary is selected
 automatically based on `process.platform` and `process.arch`. No postinstall
 scripts are required -- the binary is included directly in the published package.
+Windows prebuilds are linked with the static MSVC C runtime, so they do not
+require users to install the Visual C++ Redistributable separately.
 
 Prebuilt binaries are produced by the `prebuild.yml` GitHub Actions workflow,
 which cross-compiles on CI for all target triples.

docs/getting-started/install.md

@@ -62,6 +62,9 @@ No install-time source build runs for unsupported targets. If a matching
 prebuilt binary is not available, build from a repository checkout with
 `npm run build:native`.
 
+Windows prebuilt binaries do not require a separate Visual C++ Redistributable
+install.
+
 ## Package Overview
 
 | Package | Description | Required |

docs/packages/native.md

@@ -5,6 +5,7 @@ Native addon:
 - Rust + `napi-rs` binding
 - vendored Zireael engine sources
 - prebuilt `.node` binaries for supported targets
+- static MSVC runtime linking for Windows prebuilds
 
 ## Install
 

packages/native/README.md

@@ -29,6 +29,8 @@ npm run check:native-vendor
 - Engine placement is controlled by `@rezi-ui/node` `executionMode` (`auto` | `worker` | `inline`).
 - `executionMode: "auto"` selects inline when `fpsCap <= 30`, worker otherwise.
 - All buffers across the boundary are caller-owned; binary formats are validated strictly.
+- Windows builds link the MSVC C runtime statically so packaged apps do not need
+  a separate Visual C++ Redistributable install.
 - Native compilation reads `packages/native/vendor/zireael` (not `vendor/zireael`).
 - `packages/native/vendor/VENDOR_COMMIT.txt` must match the `vendor/zireael` gitlink commit.
 

packages/native/build.rs

@@ -14,6 +14,13 @@ fn main() {
     build.include(&src_dir);
     build.warnings(false);
 
+    let target_features = env::var("CARGO_CFG_TARGET_FEATURE").unwrap_or_default();
+    if env::var("CARGO_CFG_TARGET_ENV").as_deref() == Ok("msvc")
+        && target_features.split(',').any(|feature| feature == "crt-static")
+    {
+        build.static_crt(true);
+    }
+
     // The engine assumes a C99-or-newer compiler; C11 is required for atomics on MSVC.
     if build.get_compiler().is_like_msvc() {
         build.flag_if_supported("/std:c11");

packages/native/scripts/build-native.mjs

@@ -3,6 +3,8 @@ import { copyFileSync, existsSync, readdirSync, rmSync, writeFileSync } from "no
 import { tmpdir } from "node:os";
 import { delimiter, join } from "node:path";
 
+const WINDOWS_STATIC_CRT_RUSTFLAGS = "-C target-feature=+crt-static";
+
 function splitPathList(value, delim) {
   return value
     .split(delim)
@@ -338,6 +340,25 @@ function withRustToolchainOnPath(env) {
   return next;
 }
 
+function isWindowsMsvcTarget(targetTriple) {
+  return typeof targetTriple === "string" && targetTriple.endsWith("-pc-windows-msvc");
+}
+
+function withWindowsStaticCrtEnv(env, hostTargetTriple) {
+  if (process.platform !== "win32" || !isWindowsMsvcTarget(hostTargetTriple)) return env;
+
+  const current = typeof env.RUSTFLAGS === "string" ? env.RUSTFLAGS.trim() : "";
+  if (/(^|\s)target-feature=\+crt-static(\s|$)/.test(current)) return env;
+  if (/(^|\s)-Ctarget-feature=\+crt-static(\s|$)/.test(current)) return env;
+
+  const next = { ...env };
+  next.RUSTFLAGS =
+    current.length > 0
+      ? `${current} ${WINDOWS_STATIC_CRT_RUSTFLAGS}`
+      : WINDOWS_STATIC_CRT_RUSTFLAGS;
+  return next;
+}
+
 function buildWithCargoDirectly(env, host) {
   const cargoExe = getCargoExePath(env) ?? "cargo";
   try {
@@ -405,7 +426,10 @@ try {
 }
 
 const scriptEnv = ensureCargoOnPath(
-  withWindowsSdkEnv(withMsvcDevEnv(withRustToolchainOnPath(process.env), host), host),
+  withWindowsStaticCrtEnv(
+    withWindowsSdkEnv(withMsvcDevEnv(withRustToolchainOnPath(process.env), host), host),
+    host,
+  ),
 );
 
 // @napi-rs/cli parses Cargo.toml by running `cargo metadata` through cmd.exe on Windows.

scripts/__tests__/native-windows-static-crt.test.mjs

@@ -0,0 +1,64 @@
+import { strict as assert } from "node:assert";
+import { readFileSync } from "node:fs";
+import { describe, test } from "node:test";
+import { fileURLToPath } from "node:url";
+
+const BUILD_RS_PATH = fileURLToPath(new URL("../../packages/native/build.rs", import.meta.url));
+const BUILD_NATIVE_SCRIPT_PATH = fileURLToPath(
+  new URL("../../packages/native/scripts/build-native.mjs", import.meta.url),
+);
+const PREBUILD_WORKFLOW_PATH = fileURLToPath(
+  new URL("../../.github/workflows/prebuild.yml", import.meta.url),
+);
+const RELEASE_WORKFLOW_PATH = fileURLToPath(
+  new URL("../../.github/workflows/release.yml", import.meta.url),
+);
+
+const STATIC_CRT_RUSTFLAGS = "-C target-feature=+crt-static";
+
+function assertWindowsPrebuildUsesStaticCrt(workflow, label) {
+  assert.match(
+    workflow,
+    new RegExp(
+      [
+        "- name: Build prebuild",
+        "[\\s\\S]*?env:",
+        `[\\s\\S]*?RUSTFLAGS: \\$\\{\\{ runner\\.os == 'Windows' && '${STATIC_CRT_RUSTFLAGS.replace("+", "\\+")}' \\|\\| '' \\}\\}`,
+        '[\\s\\S]*?run: npx napi build --platform --release --target "\\$\\{\\{ matrix\\.rustTarget \\}\\}" --js false',
+      ].join("\\n?"),
+      "u",
+    ),
+    `${label} Windows prebuilds must pass Rust +crt-static`,
+  );
+}
+
+describe("native Windows CRT linking", () => {
+  test("local Windows native builds use static MSVC CRT", () => {
+    const buildRs = readFileSync(BUILD_RS_PATH, "utf8");
+    const buildScript = readFileSync(BUILD_NATIVE_SCRIPT_PATH, "utf8");
+
+    assert.match(buildRs, /CARGO_CFG_TARGET_ENV"\)\.as_deref\(\) == Ok\("msvc"\)/);
+    assert.match(
+      buildRs,
+      /target_features\.split\(','\)\.any\(\|feature\| feature == "crt-static"\)/,
+    );
+    assert.match(buildRs, /build\.static_crt\(true\)/);
+    assert.match(
+      buildScript,
+      /const WINDOWS_STATIC_CRT_RUSTFLAGS = "-C target-feature=\+crt-static";/,
+    );
+    assert.match(buildScript, /function isWindowsMsvcTarget\(targetTriple\)/);
+    assert.match(buildScript, /function withWindowsStaticCrtEnv\(env, hostTargetTriple\)/);
+  });
+
+  test("published Windows native prebuilds use static MSVC CRT", () => {
+    assertWindowsPrebuildUsesStaticCrt(
+      readFileSync(PREBUILD_WORKFLOW_PATH, "utf8"),
+      "manual prebuild workflow",
+    );
+    assertWindowsPrebuildUsesStaticCrt(
+      readFileSync(RELEASE_WORKFLOW_PATH, "utf8"),
+      "release workflow",
+    );
+  });
+});