dockerignore-misses-noisy-build-context-paths

Detects Docker build contexts where a .dockerignore file exists but still allows noisy root paths into the build context.

This rule looks for visible paths such as:

• .git
• .github
• node_modules
• dist
• build
• .next
• .turbo
• coverage

Why it matters:

• Broad COPY and ADD instructions can include these paths in image layers.
• Generated output, dependency folders, VCS metadata, and CI metadata can increase context transfer time and image size.
• These paths also change often, which can invalidate Docker cache layers unnecessarily.

What to do:

• Add ignore entries for noisy paths that are not intentionally copied into the image.
• Keep .dockerignore next to the Docker build context, not only at the repository root when building a subdirectory context.
• Measure Docker build context size and broad COPY layer size before and after tightening the ignore file.