CopyIgnoredFile warning when Dockerfile is in different directory than .dockerignore

Description

I work with a monorepo that has several Dockerfiles for individual images, including one in the repository root. The root also contains a .dockerignore file that applies when the root directory is used as the docker build context. The other Dockerfiles are in subdirectories, and are built with those subdirectories as their context.

The Docker extension is giving me a CopyIgnoredFile in a Dockerfile stored in a subdirectory, even though that subdirectory does not have a .dockerignore file. In essence it seems to be using the .dockerignore file from the root repository to apply it to the subdirectory Dockerfile. This is not a problem when using docker build outside of vscode, only the warning is the problem here.

Visual Studio Code version

1.109.2
591199df409fbf59b4b52d5ad4ee0470152a9b31
x64

Installed extensions in Visual Studio Code

13xforever.language-x86-64-assembly@3.1.5
charliermarsh.ruff@2026.36.0
coderabbit.coderabbit-vscode@0.17.0
davidanson.vscode-markdownlint@0.61.1
dbaeumer.vscode-eslint@3.0.20
deque-systems.vscode-axe-linter@4.11.0
docker.docker@0.18.0
dorzey.vscode-sqlfluff@3.7.0
eamodio.gitlens@17.10.0
editorconfig.editorconfig@0.18.1
esbenp.prettier-vscode@12.3.0
exiasr.hadolint@1.1.2
github.copilot-chat@0.37.5
github.vscode-pull-request-github@0.128.0
longfish801.regexpoutline@1.1.0
mechatroner.rainbow-csv@3.24.1
ms-azuretools.vscode-containers@2.4.1
ms-azuretools.vscode-docker@2.0.0
ms-ossdata.vscode-pgsql@1.16.0
ms-python.black-formatter@2025.2.0
ms-python.debugpy@2025.18.0
ms-python.python@2026.0.0
ms-python.vscode-pylance@2025.10.4
ms-python.vscode-python-envs@1.16.0
ms-toolsai.jupyter@2025.9.1
ms-toolsai.jupyter-keymap@1.1.2
ms-toolsai.jupyter-renderers@1.3.0
ms-toolsai.vscode-jupyter-cell-tags@0.1.9
ms-toolsai.vscode-jupyter-slideshow@0.1.6
ms-vscode.cmake-tools@1.22.27
ms-vscode.cpptools@1.30.5
ms-vscode.cpptools-extension-pack@1.3.1
ms-vscode.cpptools-themes@2.0.0
ms-vscode.makefile-tools@0.12.17
netcorext.uuid-generator@0.0.5
orta.vscode-twoslash-queries@1.5.1
pdconsec.vscode-print@1.6.0
redhat.java@1.52.0
redhat.vscode-yaml@1.19.1
reteps.htmlmustache-lsp@0.0.15
sqlfluff.vscode-sqlfluff@4.0.0
supabase.postgrestools@1.4.0
tamasfe.even-better-toml@0.21.2
tobermory.es6-string-html@2.17.0
twxs.cmake@0.0.17
vadimcn.vscode-lldb@1.12.1
vitest.explorer@1.44.0
vscjava.vscode-gradle@3.17.2
vscjava.vscode-java-dependency@0.27.0
vscjava.vscode-java-pack@0.30.5
vscjava.vscode-maven@0.45.1

Additional info

The repo in question is this: https://github.com/PrairieLearn/PrairieLearn. In particular note that there are Dockerfiles in the root as well as in subdirectories of images, graders and workspaces. Only the root and two of the many images have .dockerignore files.

Reproduce the warning with the root Dockerfile, nested Dockerfiles under images, graders, or workspaces, and the available root or nested .dockerignore files in PrairieLearn. Compare the warning's ignore-file selection with the Docker build context; done when CopyIgnoredFile is evaluated only against the relevant context's .dockerignore.