pnpm + Next.js SSG で作成したページを GitHub Pages にデプロイする

/** @type {import('next').NextConfig} */
const nextConfig = {
  output: 'export',
};

module.exports = nextConfig;

Error: Unable to locate executable file: pnpm. Please verify either the file path exists or the file can be found within a directory specified by the PATH environment variable. Also check the file mode to verify the file is executable.

# Sample workflow for building and deploying a Next.js site to GitHub Pages
#
# To get started with Next.js see: https://nextjs.org/docs/getting-started
#
name: Deploy Next.js site to Pages

on:
  # Runs on pushes targeting the default branch
  push:
    branches: ['master']

  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:

# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
permissions:
  contents: read
  pages: write
  id-token: write

# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
concurrency:
  group: 'pages'
  cancel-in-progress: false

jobs:
  # Build job
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Detect package manager
        id: detect-package-manager
        run: |
          if [ -f "${{ github.workspace }}/yarn.lock" ]; then
            echo "manager=yarn" >> $GITHUB_OUTPUT
            echo "command=install" >> $GITHUB_OUTPUT
            echo "runner=yarn" >> $GITHUB_OUTPUT
            exit 0
          elif [ -f "${{ github.workspace }}/pnpm-lock.yaml" ]; then
            echo "manager=pnpm" >> $GITHUB_OUTPUT
            echo "command=install --frozen-lockfile" >> $GITHUB_OUTPUT
            echo "runner=pnpm" >> $GITHUB_OUTPUT
            npm install -g pnpm
            exit 0
          elif [ -f "${{ github.workspace }}/package.json" ]; then
            echo "manager=npm" >> $GITHUB_OUTPUT
            echo "command=ci" >> $GITHUB_OUTPUT
            echo "runner=npx --no-install" >> $GITHUB_OUTPUT
            exit 0
          else
            echo "Unable to determine package manager"
            exit 1
          fi
      - name: Setup Node
        uses: actions/setup-node@v4
        with:
          node-version-file: '.node-version'
          cache: ${{ steps.detect-package-manager.outputs.manager }}
      - name: Setup Pages
        uses: actions/configure-pages@v4
        with:
          # Automatically inject basePath in your Next.js configuration file and disable
          # server side image optimization (https://nextjs.org/docs/api-reference/next/image#unoptimized).
          #
          # You may remove this line if you want to manage the configuration yourself.
          static_site_generator: next
      - name: Restore cache
        uses: actions/cache@v4
        with:
          path: |
            .next/cache
          # Generate a new cache whenever packages or source files change.
          key: ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock', '**/pnpm-lock.yaml') }}-${{ hashFiles('**.[jt]s', '**.[jt]sx') }}
          # If source files changed but packages didn't, rebuild from a prior cache.
          restore-keys: |
            ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock', '**/pnpm-lock.yaml') }}-
      - name: Install dependencies
        run: ${{ steps.detect-package-manager.outputs.runner }} ${{ steps.detect-package-manager.outputs.command }}
      - name: Build with Next.js
        run: ${{ steps.detect-package-manager.outputs.runner }} next build
      - name: List files after build
        run: ls -al
      - name: Upload artifact
        uses: actions/upload-pages-artifact@v3
        with:
          path: ./out

  # Deployment job
  deploy:
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    runs-on: ubuntu-latest
    needs: build
    steps:
      - name: Deploy to GitHub Pages
        id: deployment
        uses: actions/deploy-pages@v4

elif [ -f "${{ github.workspace }}/pnpm-lock.yaml" ]; then
  echo "manager=pnpm" >> $GITHUB_OUTPUT
  echo "command=install --frozen-lockfile" >> $GITHUB_OUTPUT
  echo "runner=pnpm" >> $GITHUB_OUTPUT
  npm install -g pnpm
  exit 0

key: ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock', '**/pnpm-lock.yaml') }}-${{ hashFiles('**.[jt]s', '**.[jt]sx') }}

restore-keys: |
  ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json', '**/yarn.lock', '**/pnpm-lock.yaml') }}-

const updateEnvPath = (filename: string) => {
  const isProd = process.env.NODE_ENV === 'production';
  const prefixPath = isProd ? '/repository-name' : '';

  return prefixPath + filename;
};

export default updateEnvPath;

<img src={updateEnvPath('hoge.jpg')} alt='' />