Better diagnostics for download errors

src/main/src/downloading/downloader.ts

@@ -142,16 +142,24 @@ export async function download<T>(
     const fd = await open(dest, flag);
     handle = { fd, path: dest };
   } catch (err) {
-    throw new DownloadError({ code: "fs-error", path: dest }, `Failed to open ${dest}`, err);
+    const errno = getErrorCode(err) ?? undefined;
+    throw new DownloadError(
+      { code: "fs-error", path: dest, errno },
+      errno ? `Failed to open ${dest} (${errno})` : `Failed to open ${dest}`,
+      err,
+    );
   }
 
   if (checkpoint && probe.size) {
     try {
       await handle.fd.truncate(probe.size);
     } catch (err) {
+      const errno = getErrorCode(err) ?? undefined;
       throw new DownloadError(
-        { code: "fs-error", path: handle.path },
-        `Failed to truncate ${handle.path}`,
+        { code: "fs-error", path: handle.path, errno },
+        errno
+          ? `Failed to truncate ${handle.path} (${errno})`
+          : `Failed to truncate ${handle.path}`,
         err,
       );
     }
@@ -432,9 +440,12 @@ async function downloadStream(
         if (progress) progress.bytesWritten += result.bytesWritten;
         writePosition += result.bytesWritten;
       } catch (err) {
+        const errno = getErrorCode(err) ?? undefined;
         throw new DownloadError(
-          { code: "fs-error", path: handle.path },
-          `Failed to write to ${handle.path}`,
+          { code: "fs-error", path: handle.path, errno },
+          errno
+            ? `Failed to write to ${handle.path} (${errno})`
+            : `Failed to write to ${handle.path}`,
           err,
         );
       }

src/renderer/src/extensions/download_management/views/DownloadView.tsx

@@ -422,6 +422,8 @@ class DownloadView extends ComponentEx<IDownloadViewProps, IComponentState> {
     }
     const urlInvalid = ["moved permanently", "forbidden", "gone"];
     const title = resume ? "Failed to resume download" : "Failed to start download";
+    // Fall back to `err.code` for raw Node errors that reach here directly.
+    const errno: string | undefined = err.payload?.errno ?? err.code;
     if (err instanceof ProcessCanceled) {
       this.props.onShowError(title, err, undefined, false);
     } else if (err instanceof UserCanceled) {
@@ -526,9 +528,9 @@ class DownloadView extends ComponentEx<IDownloadViewProps, IComponentState> {
         undefined,
         false,
       );
-    } else if (err.code === "ENOSPC") {
+    } else if (errno === "ENOSPC") {
       this.props.onShowError(title, "The disk is full", undefined, false);
-    } else if (err.code === "EBADF") {
+    } else if (errno === "EBADF") {
       this.props.onShowError(
         title,
         "Failed to write to disk. If you use a removable media or " +

src/shared/src/download-errors.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+
+import { downloadErrorToWire, wireToDownloadError } from "./download-errors";
+import { DownloadError } from "./types/errors";
+
+const fsErrorErrno = (err: unknown): string | undefined =>
+  err instanceof DownloadError && err.payload.code === "fs-error" ? err.payload.errno : undefined;
+
+describe("download-errors wire codec", () => {
+  it("preserves the fs-error errno across the wire", () => {
+    const wire = downloadErrorToWire(
+      new DownloadError(
+        { code: "fs-error", path: "C:/tmp/__vortex_tmp_0001", errno: "ENOSPC" },
+        "Failed to write to C:/tmp/__vortex_tmp_0001 (ENOSPC)",
+      ),
+    );
+    const wireErrno = wire.payload.code === "fs-error" ? wire.payload.errno : undefined;
+    expect(wireErrno).toBe("ENOSPC");
+
+    const rebuilt = wireToDownloadError(wire);
+    expect(rebuilt).toBeInstanceOf(DownloadError);
+    expect(fsErrorErrno(rebuilt)).toBe("ENOSPC");
+    expect(rebuilt.message).toContain("ENOSPC");
+  });
+
+  it("tolerates an fs-error with no errno", () => {
+    const rebuilt = wireToDownloadError(
+      downloadErrorToWire(
+        new DownloadError({ code: "fs-error", path: "C:/tmp/x" }, "Failed to write to C:/tmp/x"),
+      ),
+    );
+    expect(rebuilt).toBeInstanceOf(DownloadError);
+    expect(fsErrorErrno(rebuilt)).toBeUndefined();
+  });
+});

src/shared/src/types/errors.ts

@@ -6,7 +6,7 @@ export type DownloadErrorPayload =
   | { code: "precondition-failed"; url: URL }
   | { code: "protocol-violation"; url: URL }
   | { code: "is-html"; url: URL }
-  | { code: "fs-error"; path: string }
+  | { code: "fs-error"; path: string; errno?: string }
   | { code: "resolver-error" };
 
 export class DownloadError extends Error {