EISDIR: [commonjs--resolver] Is a directory when building with react-router

[jdmcd]

I am building my react-router / remix app (in framework mode) using the recommended react-router build command. I am also using Bun. My Dockerfile looks like this:

FROM oven/bun:1 AS base
WORKDIR /usr/src/app

# install dependencies into temp directory
# this will cache them and speed up future builds
FROM base AS install
RUN mkdir -p /temp/dev
COPY package.json bun.lockb /temp/dev/
RUN cd /temp/dev && bun install --frozen-lockfile

# install with --production (exclude devDependencies)
RUN mkdir -p /temp/prod
COPY package.json bun.lockb /temp/prod/
RUN cd /temp/prod && bun install --frozen-lockfile

# copy node_modules from temp directory
# then copy all (non-ignored) project files into the image
FROM base AS prerelease
COPY --from=install /temp/dev/node_modules node_modules
COPY . .
RUN bunx prisma generate

# build
ENV NODE_ENV=production
RUN bun run build
RUN bun playwright-core install chromium
RUN bun playwright-core install-deps chromium

# copy production dependencies and source code into final image
FROM base AS release
COPY --from=install /temp/prod/node_modules node_modules
COPY --from=prerelease /usr/src/app .

# run the app
USER bun
EXPOSE 3000/tcp
ENTRYPOINT [ "bun", "run", "start" ]

The build process fails on the bun run build step with the following error:

 > [build-env 4/4] RUN bun run build:                                                                 
#14 0.240 $ cross-env NODE_ENV=production react-router build                                          
#14 1.555 vite v5.4.11 building for production...                                                     
#14 1.709 transforming...                                                                             
#14 3.604 ✓ 1555 modules transformed.                                                                 
#14 3.615 x Build failed in 2.01s
#14 3.617 16585 |     path$n.dirname(nearestPackage.dir),
#14 3.617 16586 |     packageCache
#14 3.617 16587 |   ));
#14 3.617 16588 | }
#14 3.617 16589 | function loadPackageData(pkgPath) {
#14 3.617 16590 |   const data = JSON.parse(fs__default.readFileSync(pkgPath, "utf-8"));
#14 3.617         ^
#14 3.617 EISDIR: [commonjs--resolver] Is a directory
#14 3.617    errno: -21
#14 3.617     code: "PLUGIN_ERROR"
#14 3.617  syscall: "read"
#14 3.617       fd: 940
#14 3.617 
#14 3.617       at readFileSync (native:1:1)
#14 3.617       at loadPackageData (/app/node_modules/vite/dist/node/chunks/dep-CB_7IfJ-.js:16590:38)
#14 3.617       at tryCleanFsResolve (/app/node_modules/vite/dist/node/chunks/dep-CB_7IfJ-.js:46388:22)
#14 3.617       at tryFsResolve (/app/node_modules/vite/dist/node/chunks/dep-CB_7IfJ-.js:46322:14)
#14 3.617 
#14 3.702 error: script "build" exited with code 1
------
executor failed running [/bin/sh -c bun run build]: exit code: 1

I can't find much about this online and ChatGPT thinks it has something to do with a misplaced/named package.json file, but I can't find anything like that. Has anyone experienced this? This doesn't happen when I build with yarn.