-[hash] changes based on the absolute file path

[jenseng]

What version of Remix are you using?

1.2.1

Steps to Reproduce

1. Create two remix projects (via npx create-remix@latest)
2. npm run build them both
3. Compare the contents of public/build

Expected Behavior

The hashes and contents of all files should be the same.

For context, I need to run my server and browser builds in two different places because Reasons™. If they are not deterministic, the server build will expect different filenames than what the browser build creates, which results in 404s and a broken app.

Actual Behavior

1. The public/build/routes/index-[hash].js files are identical but have different hashes.
2. The public/build/root-[hash].js files are identical but have different hashes.
3. The public/build/manifest-[hash].js files have different contents and different hashes (due to 1 and 2)

I've confirmed the behavior is deterministic based on the project directory. I.e. you can mv your projects around to swap their locations; if you build again you'll get the hashes/files originally seen in the other project.

In a larger remix app, I've also observed minification differences (different shortened variable names), likely due to the same issue.

While this may be an esbuild bug, it could also be caused by remix' virtual modules including the absolute path (more context from a similar bug report).

I'll take a stab at fixing this 😄 🤞

[jenseng]

Assuming you can't control where your code gets checked out and run, here's a silly hack you can use until the fix gets merged/released.

1. make a delete-me-once-remix-builds-are-deterministic.js file like so

// make path.resolve and friends NOT resolve symlinks, so we can fully control the absolute paths
// uses in its virtual modules
process.cwd = () => process.env.PWD;

2. just prior to invoking a remix build (e.g. in your build scripts or wherever):

# make a deterministic symlink path, cd into it, and build from there using the symlink hack file above.
ln -sf "$(pwd)" /tmp/_remix_pwd_hack
cd /tmp/_remix_pwd_hack
export NODE_OPTIONS="$NODE_OPTIONS -r ./delete-me-once-remix-builds-are-deterministic"

[jenseng]

Still broken on 1.4.x, the fix (#2027) has been rebased to the latest (new integration test fails on dev, passes with the fix)

[jenseng]

So it turns out that the silly hack above breaks emptyModulesPlugin's check (e.g. for /\.server(\.[jt]sx?)?$/ files), since args.resolveDir comes from esbuild and reflects the real/original path, whereas config.appDirectory has the hacky path

This new problem can be hackily hacked around by hooking into the esbuild config along these lines and patching/injecting plugins to correct any wrong resolvePaths. But it would be nice to just get the PR merged so these layered hacks aren't needed 🙃