I have a small empty SvelteKit template project which runs well locally but when I try Dockerizing it fails.

Can anyone help me understand why isn’t the build found?

This is the Dockerfile:

FROM node:lts-slim AS deps
WORKDIR /app
COPY package.json pnpm-lock.yaml ./
RUN npx pnpm i --frozen-lockfile

FROM node:lts-slim AS builder
WORKDIR /app
COPY . .
COPY --from=deps /app/node_modules ./node_modules
RUN npx pnpm run build

FROM node:lts-slim AS runner
WORKDIR /app
ENV NODE_ENV production

RUN useradd -u 1001 -s /usr/sbin/nologin -m -d /home/sveltekit sveltekit
RUN groupadd nodejs && usermod -aG nodejs sveltekit
COPY --from=builder --chown=sveltekit:nodejs /app/build ./build
COPY --from=builder /app/node_modules ./node_modules
COPY --from=builder /app/package.json ./package.json

USER sveltekit
EXPOSE 3000

CMD ["node", "./build"]

the is the package.json file:

{
    "name": "sveltekit-docker",
    "version": "0.0.1",
    "private": true,
    "scripts": {
        "dev": "vite dev",
        "build": "vite build",
        "preview": "vite preview",
        "lint": "prettier --check . && eslint .",
        "format": "prettier --write ."
    },
    "devDependencies": {
        "@sveltejs/adapter-auto": "^3.0.0",
        "@sveltejs/kit": "^2.0.0",
        "@sveltejs/vite-plugin-svelte": "^3.0.0",
        "@types/eslint": "^8.56.0",
        "eslint": "^8.56.0",
        "eslint-config-prettier": "^9.1.0",
        "eslint-plugin-svelte": "^2.35.1",
        "prettier": "^3.1.1",
        "prettier-plugin-svelte": "^3.1.2",
        "svelte": "^4.2.7",
        "vite": "^5.0.3"
    },
    "type": "module"
}

and this is the (partially redacted eliminating first steps with no error) error trace:

bob ~/code/sveltekit_docker [main] $ docker build -t sd --no-cache .
[+] Building 8.9s (15/17)                                  docker:desktop-linux
 => [internal] load build definition from Dockerfile                       0.0s
... lines without errors omitted....
 => [deps 4/4] RUN npx pnpm i --frozen-lockfile                            4.1s
 => [builder 4/5] COPY --from=deps /app/node_modules ./node_modules        0.3s
 => [builder 5/5] RUN npx pnpm run build                                   3.1s
 => ERROR [runner 5/7] COPY --from=builder --chown=sveltekit:nodejs /app/  0.0s
------
[runner 5/7] COPY --from=builder --chown=sveltekit:nodejs /app/build ./build:
------
Dockerfile:18
--------------------
  16 |     RUN useradd -u 1001 -s /usr/sbin/nologin -m -d /home/sveltekit sveltekit
  17 |     RUN groupadd nodejs && usermod -aG nodejs sveltekit
  18 | >>> COPY --from=builder --chown=sveltekit:nodejs /app/build ./build
  19 |     COPY --from=builder /app/node_modules ./node_modules
  20 |     COPY --from=builder /app/package.json ./package.json
--------------------
ERROR: failed to solve: failed to compute cache key: failed to calculate checksum of ref 7b0a430b-35d6-4fc8-a6dd-db95ac242422::eeh419kyu0c4wj7k9gabjqe4w: "/app/build": not found