[Bug] @huggingface/transformers model cache writes inside read-only asar, memory indexing fails with ENOTDIR #88

Environment

• macOS Apple Silicon (arm64)
• Memmy v1.0.3 (unsigned DMG built from source)
• Dependency: @huggingface/transformers (Xenova/all-MiniLM-L6-v2 model)

Description

After fixing the dylib issue (#76), the memory service starts but indexing fails when it tries to download and cache the embedding model. The @huggingface/transformers library attempts to create a .cache/ directory inside the module's path, which resolves to inside the read-only app.asar archive.

Error

ENOTDIR: not a directory, mkdir '/Applications/Memmy.app/Contents/Resources/app.asar/dist/runtime/memory/node_modules/@huggingface/transformers/.cache/Xenova/all-MiniLM-L6-v2/onnx'

Root Cause

In Memory/src/model/embedder.ts, the ensureLocalExtractor function loads the model via:

const mod = await import("@huggingface/transformers");
const pipeline = mod.pipeline;
return await pipeline("feature-extraction", model, { dtype: "q8", device: "cpu" });

No cache_dir or env.cacheDir is configured, so the library defaults to .cache/ relative to the module directory. Inside a packaged Electron app, this path is inside the read-only asar archive.

Workaround

Patch the compiled embedder.js to set a writable cache directory before loading the pipeline:

const mod = await import("@huggingface/transformers");
const { homedir } = await import("node:os");
const { join } = await import("node:path");
mod.env.cacheDir = join(homedir(), ".memmy", "transformers-cache");

Suggested Fix

In Memory/src/model/embedder.ts, set env.cacheDir to a writable location (e.g., ~/.memmy/transformers-cache or the app's userData directory) before calling pipeline(). This ensures the model cache survives app updates and is writable in packaged builds.