failed to calculate checksum of ref

[netsurion-jsayre]

New to Docker. Using Ubuntu 20.04.6LTS. Using docker file "Dockerfile.ubuntu" and ".dockerignore" file in my directory. I realize that the provided Dockerfile is for 22.04, and am hoping that's not my issue. Anyway, getting below error.

ERROR: failed to solve: failed to compute cache key: failed to calculate checksum of ref TJDJ:TJG5:3FRL:MTEA:NIET:UVVI:MRJU:XFAX:XLC5:GUZE:2ZNY:WOCC::hns4t44fjx7oot0q2zc7ymhcz: "/aspnetapp": not found

This error is received when execute sudo docker build --force-rm=true --no-cache=true . and variations (tagging, not using no-cache, etc.). If I sudo docker run the sample image, I have no issues. I have also tried executing the build from a higher-level directory and specifying the directory of the Dockerfile, but that has not worked either. Google-fu has failed, ChatGPT suggested I restart docker (haha), and I haven't seen anything else that really seems similar. Thoughts? Below my sig are my Dockerfile and .dockerignore. Sorry for lousy formatting, I always seem to jack that up as I don't do this much. Thanks in advance.
-jcs

Dockerfile

# Learn about building .NET container images:
# https://github.com/dotnet/dotnet-docker/blob/main/samples/README.md
FROM mcr.microsoft.com/dotnet/sdk:7.0-jammy AS build
WORKDIR /source

# copy csproj and restore as distinct layers
COPY aspnetapp/*.csproj .
RUN dotnet restore --use-current-runtime

# copy everything else and build app
COPY aspnetapp/. .
RUN dotnet publish --use-current-runtime --self-contained false --no-restore -o /app

# final stage/image
FROM mcr.microsoft.com/dotnet/aspnet:7.0-jammy
WORKDIR /app
COPY --from=build /app .
ENTRYPOINT ["./aspnetapp"]

.dockerignore

# directories
**/bin/
**/obj/
**/out/

# files
Dockerfile*
**.*.md

[mthalman]

What is your current working directory when executing the docker build command? That is the directory that you are setting as your build context, via the . character at the very end of your command arguments. And that means any COPY instructions in your Dockerfile are relative to that directory. So that directory should contain the aspnetapp directory that you reference in COPY aspnetapp/*.csproj .. If you want to specify a different directory as your build context, you should replace the . in your docker build command with the path that you do want.

[netsurion-jsayre]

Well, that solved that problem, thanks a ton. But it introduced a new one. Screenshot below. I will try to work through it on my own and mark this as the answer. Thanks again!