fix(memory-wiki): normalize source page stat guard

TurboTheTurtle · TurboTheTurtle · commit 465628459b41 · 2026-05-18T15:22:35.000-07:00
diff --git a/extensions/memory-wiki/src/bridge.test.ts b/extensions/memory-wiki/src/bridge.test.ts
@@ -346,10 +346,14 @@ describe("syncMemoryWikiBridgeSources", () => {
     await expect(fs.readFile(externalTarget, "utf8")).resolves.toBe("external target\n");
   });
 
-  it("reports non-symlink bridge source write safety failures without symlink wording", async () => {
-    const workspaceDir = await createBridgeWorkspace("not-file-workspace");
+  async function createDirectoryCollisionFixture(params: {
+    workspaceName: string;
+    vaultName: string;
+    populateDirectory?: boolean;
+  }) {
+    const workspaceDir = await createBridgeWorkspace(params.workspaceName);
     const { rootDir: vaultDir, config } = await createVault({
-      rootDir: nextCaseRoot("not-file-vault"),
+      rootDir: nextCaseRoot(params.vaultName),
       config: {
         vaultMode: "bridge",
         bridge: {
@@ -381,8 +385,19 @@ describe("syncMemoryWikiBridgeSources", () => {
     const pageAbsPath = path.join(vaultDir, pagePath);
     await fs.rm(pageAbsPath);
     await fs.mkdir(pageAbsPath);
-    await fs.writeFile(path.join(pageAbsPath, "child.md"), "blocking child\n", "utf8");
+    if (params.populateDirectory) {
+      await fs.writeFile(path.join(pageAbsPath, "child.md"), "blocking child\n", "utf8");
+    }
     await fs.writeFile(memoryPath, "# Updated Durable Memory\n", "utf8");
+    return { appConfig, config, pageAbsPath };
+  }
+
+  it("reports non-symlink bridge source write safety failures without symlink wording", async () => {
+    const { appConfig, config } = await createDirectoryCollisionFixture({
+      workspaceName: "not-file-workspace",
+      vaultName: "not-file-vault",
+      populateDirectory: true,
+    });
 
     const second = syncMemoryWikiBridgeSources({ config, appConfig });
     await expect(second).rejects.toThrow(
@@ -391,6 +406,20 @@ describe("syncMemoryWikiBridgeSources", () => {
     await expect(second).rejects.not.toThrow("through symlink");
   });
 
+  it("does not remove empty directory bridge source collisions as hardlinks", async () => {
+    const { appConfig, config, pageAbsPath } = await createDirectoryCollisionFixture({
+      workspaceName: "empty-directory-workspace",
+      vaultName: "empty-directory-vault",
+    });
+
+    const second = syncMemoryWikiBridgeSources({ config, appConfig });
+    await expect(second).rejects.toThrow(
+      /Refusing to write imported source page \((not-file|path-mismatch)\): sources\//u,
+    );
+    await expect(second).rejects.not.toThrow("through symlink");
+    await expect(fs.stat(pageAbsPath)).resolves.toSatisfy((stat) => stat.isDirectory());
+  });
+
   it("replaces bridge source page hardlinks without clobbering their target", async () => {
     const workspaceDir = await createBridgeWorkspace("hardlink-workspace");
     const { rootDir: vaultDir, config } = await createVault({
diff --git a/extensions/memory-wiki/src/source-page-shared.ts b/extensions/memory-wiki/src/source-page-shared.ts
@@ -8,6 +8,23 @@ import {
 
 type ImportedSourceState = Parameters<typeof shouldSkipImportedSourceWrite>[0]["state"];
 
+type FileStatLike = {
+  isFile?: unknown;
+  nlink?: unknown;
+};
+
+function isRegularFileStat(value: unknown): value is FileStatLike & { nlink: number } {
+  if (!value || typeof value !== "object") {
+    return false;
+  }
+  const stat = value as FileStatLike;
+  const isFile =
+    typeof stat.isFile === "function"
+      ? (stat.isFile as () => boolean).call(stat)
+      : stat.isFile === true;
+  return isFile && typeof stat.nlink === "number";
+}
+
 export async function writeImportedSourcePage(params: {
   vaultRoot: string;
   syncKey: string;
@@ -51,7 +68,7 @@ export async function writeImportedSourcePage(params: {
   const existing = pageStat ? await vault.readText(params.pagePath).catch(() => "") : "";
   if (existing !== rendered) {
     try {
-      if (pageStat && pageStat.isFile && pageStat.nlink > 1) {
+      if (isRegularFileStat(pageStat) && pageStat.nlink > 1) {
         await vault.remove(params.pagePath);
       }
       await vault.write(params.pagePath, rendered);
