# prettier over the markdown, in a container, so it is never installed
# on the host. script/fmt-check-markdown builds the fmt-check stage;
# script/fmt builds fmt-out and takes the formatted files back.

# node:22-bookworm-slim, 2026-09-05
FROM node:22-bookworm-slim@sha256:83f487e0a63425e5b4d146fb5e5be574bcbe1b7b843d3ebafdd95eaf7767a7e5 AS nodedeps

# prettier lives outside /src so that a `COPY . .` of the repo cannot
# overwrite it, and so that node_modules never appears in the tree
# prettier is about to walk.
WORKDIR /tools

# package.json pins the version and yarn.lock pins the bytes:
# --frozen-lockfile installs exactly the lockfile's resolution and fails
# if package.json disagrees with it, so the tool cannot float between
# runs. yarn is the one in the image above.
COPY package.json yarn.lock ./
RUN yarn install --frozen-lockfile --non-interactive --no-progress

ENV PATH="/tools/node_modules/.bin:${PATH}"

WORKDIR /src

# Read-only markdown check. Must match $stage in
# script/fmt-check-markdown.
FROM nodedeps AS fmt-check

COPY . .

# --config, not discovery: a .prettierrc that failed to arrive would
# otherwise leave prettier on its defaults, where proseWrap is "preserve"
# and every wrap this check exists to enforce passes. Missing the file is
# a hard error instead. --no-editorconfig for the same reason in reverse:
# .editorconfig is not in the build context, so honouring it here and on
# a developer's machine would be two different answers.
RUN prettier --config .prettierrc --no-editorconfig --check "**/*.md"

# Write path. Not a check: script/fmt builds this and takes the files.
FROM nodedeps AS fmt

COPY . .

RUN prettier --config .prettierrc --no-editorconfig --write "**/*.md"

# Only the markdown leaves, with its paths intact, so that the export
# below cannot put anything else back over the caller's working tree.
RUN mkdir -p /out && cd /src && \
    find . -name '*.md' -type f -exec cp --parents '{}' /out/ ';'

# Export target: `docker build --target fmt-out --output type=local`
# writes /out's tree into a directory on the client, which is how
# script/fmt gets formatted markdown back without a bind mount.
# Must match $stage in script/fmt.
FROM scratch AS fmt-out
COPY --from=fmt /out/ /