This repo demonstrates an issue where build assets are named differently, depending on the name of the cwd folder, even if generateBuildId (in next.config.js) returns the same ID.

1. Clone this repo into two folders:

git clone https://github.com/cullylarson/nextjs-build-id-issue.git nextjs-build-id-issue-1
git clone https://github.com/cullylarson/nextjs-build-id-issue.git nextjs-build-id-issue-2

2. Build the project in both folders:

cd nextjs-build-id-issue-1
npm install
npm run build
cd ../nextjs-build-id-issue-2
npm install
npm run build

3. Diff the two build manifests:

diff nextjs-build-id-issue-1/.next/build-manifest.json nextjs-build-id-issue-2/.next/build-manifest.json

• Note that generateBuildId in next.config.js returns a constant value. The expectation is that build assets will be named the same because of this.

• If you build the project twice in the same folder, all of the asset files will be named the same. Even if you delete the .next folder and rebuild, the files will have the same names.

• This doesn't seem to be fixed by naming the project folders the same, just in different parent directories. It seems to have to do with the full cwd.

• I've also tried building in one of the project folders, saving the build-manifest.json file, deleting the entire project folder, re-cloning to the same folder name, building again, and comparing the next build-manifest.json to the old one. They're the same.

• I tried doing the "Setup" described above, saved each manifest, swapped he folder names (e.g. renamed nextjs-build-id-issue-1 to nextjs-build-id-issue-2 and vice versa), removed .nextjs, and rebuilt. The manifests matched the saved versions from their new names (i.e. the build seems to match cwd).