fix(dev-server): invalidate WRN cache by content

packages/dev-server/src/pipeline.ts

@@ -119,17 +119,21 @@ function compileWireToTs(file: string, version = 0): string {
   const cacheDir = compileCacheDir ?? join(dirname(file), ".wrnexus");
   const name = basename(file).replace(/\.wrn$/, "");
   const suffix = version ? `-hmr-${version}` : "";
-  const out = join(cacheDir, `${name}-${hashPath(file)}${suffix}.wrn.ts`);
+  const source = readFileSync(file, "utf8");
+  // Include the source contents in the cache identity. Package managers, git
+  // checkouts, archive extraction, and linked dependencies can all replace a
+  // file while preserving (or moving backwards) its mtime. An mtime-only cache
+  // then serves an older compiled component even across a clean build.
+  const out = join(cacheDir, `${name}-${hashPath(file)}-${hashPath(source)}${suffix}.wrn.ts`);
 
-  // Skip recompiling when the on-disk cache is already newer than the source
+  // The content hash makes this safe even when source timestamps are preserved.
-  // (e.g. reused across dev restarts) — avoids a read + compile + write.
   try {
-    if (statSync(out).mtimeMs >= statSync(file).mtimeMs) return out;
+    if (statSync(out).isFile()) return out;
   } catch {
     /* cache missing → compile below */
   }
 
-  const code = compileWireFile(readFileSync(file, "utf8"), file);
+  const code = compileWireFile(source, file);
   mkdirSync(cacheDir, { recursive: true });
   writeFileSync(out, code, "utf8");
   return out;

packages/dev-server/test/pipeline.test.ts

@@ -1,5 +1,5 @@
 import { expect, test } from "bun:test";
-import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { mkdtempSync, rmSync, utimesSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { invalidateModule, loadModule, setCompileCacheDir } from "../src/pipeline.ts";
@@ -41,3 +41,24 @@ test("invalidateModule recompiles changed WRN files in-process", async () => {
     rmSync(root, { recursive: true, force: true });
   }
 });
+
+test("WRN cache follows content when a replacement has an older mtime", async () => {
+  const root = mkdtempSync(join(tmpdir(), "wrnexus-cache-"));
+  const file = join(root, "component.wrn");
+  setCompileCacheDir(join(root, ".wrnexus"));
+
+  try {
+    writeFileSync(file, "component Example { view { <p>Old</p> } }\n");
+    const first = (await loadModule(file)).render as () => unknown;
+    expect(String(first())).toContain("Old");
+
+    writeFileSync(file, "component Example { view { <p>Current</p> } }\n");
+    utimesSync(file, new Date(0), new Date(0));
+    invalidateModule(file);
+
+    const current = (await loadModule(file)).render as () => unknown;
+    expect(String(current())).toContain("Current");
+  } finally {
+    rmSync(root, { recursive: true, force: true });
+  }
+});