[Bug]: `container build` under `/tmp` fails to copy directories

[JaewonHur]

I have done the following

• I have searched the existing issues
• If possible, I've reproduced the issue using the 'main' branch of this project

Steps to reproduce

mkdir -p /tmp/test
cd /tmp/test

mkdir -p srcdir
echo foo > srcdir/foo

cat > Dockerfile << 'EOF'
FROM docker.io/library/alpine:3.20

COPY srcdir /dstdir
RUN ls -al /dstdir
EOF

container build -t test -f ./Dockerfile --progress plain --no-cache .

/dstdir/foo file is missing.

Problem description

File contents must be copied when COPY srcdir /dstdir.

Environment

- OS: macOS
- Xcode: 27.0
- Container: main

Code of Conduct

• I agree to follow this project's Code of Conduct