From 7a7683488ff34fc79ae0de4432f7ca4a9cbcda20 Mon Sep 17 00:00:00 2001
From: mastertyko <11311479+mastertyko@users.noreply.github.com>
Date: Mon, 13 Apr 2026 12:48:49 +0200
Subject: [PATCH] fix(gsd): disable db mmap on darwin (#4029)

---
 src/resources/extensions/gsd/gsd-db.ts        |  2 +-
 .../extensions/gsd/tests/gsd-db.test.ts       | 30 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/resources/extensions/gsd/gsd-db.ts b/src/resources/extensions/gsd/gsd-db.ts
index a088e04d6..333d5536d 100644
--- a/src/resources/extensions/gsd/gsd-db.ts
+++ b/src/resources/extensions/gsd/gsd-db.ts
@@ -169,7 +169,7 @@ function initSchema(db: DbAdapter, fileBacked: boolean): void {
   if (fileBacked) db.exec("PRAGMA synchronous = NORMAL");
   if (fileBacked) db.exec("PRAGMA auto_vacuum = INCREMENTAL");
   if (fileBacked) db.exec("PRAGMA cache_size = -8000");   // 8 MB page cache
-  if (fileBacked) db.exec("PRAGMA mmap_size = 67108864");  // 64 MB mmap
+  if (fileBacked && process.platform !== "darwin") db.exec("PRAGMA mmap_size = 67108864");  // 64 MB mmap
   db.exec("PRAGMA temp_store = MEMORY");
   db.exec("PRAGMA foreign_keys = ON");
 
diff --git a/src/resources/extensions/gsd/tests/gsd-db.test.ts b/src/resources/extensions/gsd/tests/gsd-db.test.ts
index 0987b9ad3..97c799421 100644
--- a/src/resources/extensions/gsd/tests/gsd-db.test.ts
+++ b/src/resources/extensions/gsd/tests/gsd-db.test.ts
@@ -43,6 +43,16 @@ function cleanup(dbPath: string): void {
   }
 }
 
+function withPlatform<T>(platform: NodeJS.Platform, fn: () => T): T {
+  const original = process.platform;
+  Object.defineProperty(process, 'platform', { value: platform });
+  try {
+    return fn();
+  } finally {
+    Object.defineProperty(process, 'platform', { value: original });
+  }
+}
+
 // ═══════════════════════════════════════════════════════════════════════════
 // gsd-db tests
 // ═══════════════════════════════════════════════════════════════════════════
@@ -279,6 +289,26 @@ describe('gsd-db', () => {
     cleanup(dbPath);
   });
 
+  test('gsd-db: mmap stays disabled on darwin file-backed DBs', () => {
+    const darwinDbPath = tempDbPath();
+    withPlatform('darwin', () => {
+      openDatabase(darwinDbPath);
+      const adapter = _getAdapter()!;
+      const mmap = adapter.prepare('PRAGMA mmap_size').get();
+      assert.deepStrictEqual(mmap?.['mmap_size'], 0, 'darwin should leave mmap_size disabled');
+      cleanup(darwinDbPath);
+    });
+
+    const linuxDbPath = tempDbPath();
+    withPlatform('linux', () => {
+      openDatabase(linuxDbPath);
+      const adapter = _getAdapter()!;
+      const mmap = adapter.prepare('PRAGMA mmap_size').get();
+      assert.deepStrictEqual(mmap?.['mmap_size'], 67108864, 'non-darwin should still enable mmap_size');
+      cleanup(linuxDbPath);
+    });
+  });
+
   test('gsd-db: transaction rollback on error', () => {
     openDatabase(':memory:');