Copy command's --exclude option fails to exclude from subdirectories

[codebling]

See also #5489

Example repo

The exclude option correctly excludes files from the top-level directory in a COPY command, but incorrectly copies files matching the exclude pattern in subdirectories.

To reproduce, create a directory structure:

dir1/a.1
dir1/a.2
dir1/dir2/a.1
dir1/dir2/a.2
Dockerfile

and add these contents to the Dockerfile:

# syntax=docker.io/docker/dockerfile:1.11.1-labs
FROM scratch
COPY --exclude=*.1 dir1 .

The resulting file structure in the image will be:

dir2/a.2
dir2/a.1
a.2

a.1 is correctly excluded at the top level, but a.1 in the subdirectory is incorrectly copied

[tonistiigi]

This is the same pattern rules as .dockerignore https://docs.docker.com/build/concepts/context/#dockerignore-files . You would need to use **/*.1 for files under any level of subdirectory.

[codebling]

Confirmed **/*.1 works. Sorry for the spam