The "--output" option isn't supported when building a solution

Question

I am attempting to deploy a simply Web Api App to Azure to help me familiarise myself with Azure services and Github Actions for deployment. Below are the steps I have undertaken

1 - Create a new .NET 7 Web Api App in Visual Studio. This creates a boilerplate Weatherforecast API app and runs as expected locally through VS. 2- Create a new github repository and publish my .sln file along with the project folder to this repository

In Azure :

• Create new Web App service in my main resource group

• During creation link to my github account and select the repository and main branch where my project folder and .sln file reside.

• Now workflow file is created in the repository and deplyoment will initiate, but after a few minutes it fails with the error:

  The "--output" option isn't supported when building a solution.

I cannot see how to disable this option, below if the workflow file:

name: Build and deploy ASP.Net Core app to Azure Web App - muzztest

on:
  push:
    branches:
      - main
  workflow_dispatch:

jobs:
  build:
    runs-on: windows-latest

    steps:
      - uses: actions/checkout@v2

      - name: Set up .NET Core
        uses: actions/setup-dotnet@v1
        with:
          dotnet-version: '7.x'
          include-prerelease: true

      - name: Build with dotnet
        run: dotnet build --configuration Release

      - name: dotnet publish
        run: dotnet publish -c Release -o ${{env.DOTNET_ROOT}}/myapp

      - name: Upload artifact for deployment job
        uses: actions/upload-artifact@v2
        with:
          name: .net-app
          path: ${{env.DOTNET_ROOT}}/myapp

  deploy:
    runs-on: windows-latest
    needs: build
    environment:
      name: 'Production'
      url: ${{ steps.deploy-to-webapp.outputs.webapp-url }}

    steps:
      - name: Download artifact from build job
        uses: actions/download-artifact@v2
        with:
          name: .net-app

      - name: Deploy to Azure Web App
        id: deploy-to-webapp
        uses: azure/webapps-deploy@v2
        with:
          app-name: 'muzztest'
          slot-name: 'Production'
          publish-profile: ${{ secrets.AZUREAPPSERVICE_PUBLISHPROFILE_4F1CE8C3BB3A4BA59C822347153C6D43 }}
          package: .

What can I do to resolve the stumbling block above?

Answer 1

This is due to changes in the supported flags for .NET 7 when building solutions.

Instead of -o DIR or --output DIR you now need to use --property:PublishDir=DIR

Please see: https://learn.microsoft.com/en-us/dotnet/core/compatibility/sdk/7.0/solution-level-output-no-longer-valid for further info. Especially the Recommended action section is helpful.