Heroku Push rejected, failed to compile ASP.NET Core app - asp.net

Question

I exactly followed this link http://codersblock.com/blog/how-to-run-net-on-heroku/
to deploy the application on heroku but I am getting an error
Push rejected, failed to compile ASP.NET Core app.
when I execute git push heroku master.
If any body knows about the issue, it will be great help.
Thanks.

Answer 1

what is heroku-16?
there are different types of distros(stacks) which contains your app:
heroku-16
cedar-14 (supports dotNet-core.)
thats why we will switch to cedar-14
how to fix:
1- install heroku cli. (https://devcenter.heroku.com/articles/heroku-cli)
2- open cmd. type:
cd to/project/Root
heroku stack:set cedar-14
git push heroku master

Answer 2

You could create a Dockerfile to generate a Docker image runnable on Heroku.
FROM microsoft/aspnetcore-build:2.0 AS build-env
WORKDIR /app
# Copy csproj and restore as distinct layers
COPY *.csproj ./
RUN dotnet restore
# Copy everything else and build
COPY . ./
RUN dotnet publish -c Release -o out
# Build runtime image
FROM microsoft/aspnetcore:2.0
WORKDIR /app
COPY --from=build-env /app/out .
CMD ASPNETCORE_URLS=http://*:$PORT dotnet <YOUR_API_NAME>.dll
Then you can publish it to Heroku either directly using these Docker commands:
docker build -t aspnetapp <YOUR_API_NAME>
docker login --username=$HEROKU_USERNAME --password=$HEROKU_API_KEY registry.heroku.com
docker tag aspnetapp registry.heroku.com/$HEROKU_APP_NAME/web
docker push registry.heroku.com/$HEROKU_APP_NAME/web
In order these commands:
Create a Docker image and builds a release of your project in it
Connect to Heroku's docker registry using your credentials
Creates a new tag for your image
Publishes your image to your Heroku app
However, if your machine does not support Docker, you can also use CircleCI to run these commands. More details here:
https://www.codingnagger.com/2018/02/21/continuous-delivery/

Answer 3

I've a similar problem and spent almost the whole day debugging it.
My issue, I was using Microsoft.Net.Compilers and I'd to remove that
<PackageReference Include="Microsoft.Net.Compilers" Version="4.2.0">
<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
<PrivateAssets>all</PrivateAssets>
</PackageReference>
and add
<TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>
To .csproj (My case I was using clean architecture so I was doing these modifications in Domain layer
<PropertyGroup>
<TargetFramework>net6.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
<TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>
</PropertyGroup>
Note, I also have upgraded some of the packages it was complaining about been downgraded.