Buildkit #1039 Reproduction https://github.com/moby/buildkit/issues/1039

README.md

This reproduces moby/buildkit#1039

To reproduce:

1. vagrant up
2. vagrant ssh
3. cd /tmp
4. /vagrant/build-all-servers.sh

You should observe in the build logs that servers 2+3 are using the base image from server01 instead of what's defined in the Dockerfile.

build-all-servers.sh

#!/bin/bash
set -exuo pipefail

cd /tmp/server01/
cat Dockerfile
PROGRESS_NO_TRUNC=1 DOCKER_BUILDKIT=1 docker build \
  --progress plain -t test-bk-1:server01 -f Dockerfile .

cd ../server02/
cat Dockerfile
PROGRESS_NO_TRUNC=1 DOCKER_BUILDKIT=1 docker build \
  --progress plain -t test-bk:server02 -f Dockerfile .


cd ../server03/
cat Dockerfile
PROGRESS_NO_TRUNC=1 DOCKER_BUILDKIT=1 docker build \
  --progress plain -t test-bk:server03 -f Dockerfile .

Vagrantfile

# -*- mode: ruby -*-
# vi: set ft=ruby :

Vagrant.configure("2") do |config|
  config.vm.box = "ubuntu/bionic64"

  # Setup prerequisites
  config.vm.provision "shell", inline: <<-SHELL
    apt-get update
    apt-get install -y \
        apt-transport-https \
        ca-certificates \
        curl \
        gnupg-agent \
        software-properties-common
    curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
    add-apt-repository \
       "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
       $(lsb_release -cs) \
       stable"
    apt-get update
    apt-get install -y docker-ce docker-ce-cli containerd.io
    usermod -aG docker vagrant
  SHELL

  # Write out test Dockerfiles
  config.vm.provision "shell", inline: <<-SHELL
    mkdir -p /tmp/server01
    echo "FROM python:3.6.5" > /tmp/server01/Dockerfile
    mkdir -p /tmp/server02
    echo "FROM python:3.6.8" > /tmp/server02/Dockerfile
    mkdir -p /tmp/server03
    echo "FROM python:3.6.9" > /tmp/server03/Dockerfile
  SHELL
  
end

If I change the script in the Vagrantfile above to add sleep 2 between writing each Dockerfile the problem goes away. Maybe related to moby/buildkit#1368?