Failed to solve: lstat /var/lib/docker/tmp/buildkit-mount2554488617/target: no such file or directory

Question

New to docker, trying to build a Java Spring web app. Created a Dockerfile in my application folder 'Feedback Collection System':

>     FROM openjdk:19
>     VOLUME /tmp
>     EXPOSE 8080
>     ARG JAR_FILE=target/*.jar
>     ADD ${JAR_FILE} FeedbackColletionSystem.jar
>     ENTRYPOINT ["java","-jar","/app.jar"]

Created an artifact, builded jar file in 'out' folder if its relevant. Runed a command C:\Users\myname\IdeaProjects\Feedback Collection System> docker build -t fcs . And recieved such an error -

=> ERROR [2/2] ADD target/fcs-docker.jar app.jar                                                                  0.0s
------
  [2/2] ADD target/fcs-docker.jar app.jar:
------
Dockerfile:5
--------------------
   3 |     EXPOSE 8080
   4 |     ARG JAR_FILE=target/fcs-docker.jar
   5 | >>> ADD ${JAR_FILE} app.jar
   6 |     ENTRYPOINT ["java","-jar","/app.jar"]
--------------------
ERROR: failed to solve: failed to compute cache key: failed to calculate checksum of ref c6c2b90b-d036-468a-af5f-109679f007da::ffr4qbgvxpsv1750xol8t3sou: 
failed to walk /var/lib/docker/tmp/buildkit-mount2615739737/target: 
lstat /var/lib/docker/tmp/buildkit-mount2615739737/target: no such file or directory

Please help. Thanks.

Answer 1

I had a similar problem. It turned out that I accidentally had the target folder in .dockerignore. This meant that Docker couldn't get that folder into its build context and that's why it couldn't find it. It was probably a copy paste error from my .gitignore.

So obviously the solution was to remove the target folder from .dockerignore.