GitHub Actions Upload Artifact not finding provided path from npm run build - npm

Question

I'm trying to set up a react website using CICD principles. I can run it locally, use 'npm run build' to get a build folder, and the website works fine when I manually push the files to S3. However, when I try to run the build and deployment through github actions, the upload-artifacts step gives the following warning: 'Warning: No files were found with the provided path: build. No artifacts will be uploaded.' Obviously the deploy job then fails since it can't find any artifacts to download. Why exactly is this happening? The build folder is definitely being created since running ls after the build lists it as one of the folders in the current working directory.
name: frontend_actions
on:
workflow_dispatch:
push:
paths:
- 'frontend/'
- '.github/workflows/frontend_actions.yml'
branches:
- master
defaults:
run:
working-directory: frontend
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout#v2
- uses: actions/setup-node#v2
- name: npm install
run: npm install
- name: npm build
run: npm run build
env:
CI: false
- name: Upload Artifact
uses: actions/upload-artifact#master
with:
name: build
path: build
deploy:
needs: build
runs-on: ubuntu-latest
steps:
- uses: actions/checkout#v2
- name: Download Artifact
uses: actions/download-artifact#master
with:
name: build
path: build
- name: Deploy to S3
uses: jakejarvis/s3-sync-action#master
with:
args: --acl public-read --follow-symlinks --delete
env:
AWS_S3_BUCKET: ${{ secrets.AWS_S3_BUCKET }}
AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
AWS_REGION: 'us-west-2' # optional: defaults to us-east-1
SOURCE_DIR: 'build' # optional: defaults to entire repository

Answer 1

It turns out that my knowledge of github actions was incomplete. When setting a default working directory for jobs, the default directory is only used by commands that use 'run'. Hence all of the 'uses' actions are run in the base directory. I guess I've never encountered this issue since I've never tried uploading/downloading artifacts that weren't created in a base github directory.
Fixed the issue by changing the path from 'build/' to 'frontend/build'.