[Bug]: error is thrown when a value of undefined is encountered where loader is expected #8238
Description
System Info
System:
OS: Linux 6.11 Ubuntu 24.10 24.10 (Oracular Oriole)
CPU: (32) x64 AMD Ryzen 9 7950X 16-Core Processor
Memory: 41.08 GB / 60.88 GB
Container: Yes
Shell: 5.2.37 - /bin/bash
Binaries:
Node: 22.8.0 - ~/.volta/tools/image/node/22.8.0/bin/node
Yarn: 4.5.1 - ~/.volta/tools/image/yarn/4.5.0/bin/yarn
npm: 10.8.2 - ~/.volta/tools/image/node/22.8.0/bin/npm
Details
The following error is thrown when a value of undefined is encountered where loader is expected.
No validation error was ever thrown even though the docs mention that a strict validation is enabled by default.
Please note that I know about incompatibility with Yarn's PNP algorithm, that is not the point of this report.
The point is that the config consuming code should either filter out nil values or the validation code should shout at the user that they are supplying something fishy.
I had to go deep into the consuming code to add log-points and find out where I made a mistake (in my case, it was a forgotten reference to a loader object that I removed).
$ yarn run rspack build --config config.mjs
TypeError: Cannot read properties of undefined (reading 'type')
at .yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:11275:15
at Array.map (<anonymous>)
at getRawModuleRule (.yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:11270:36)
at .yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:11175:22
at Array.map (<anonymous>)
at getRawModule (.yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:11174:25)
at getRawOptions (.yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:10975:13)
at #getInstance (.yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:17435:24)
at #build (.yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:17351:22)
at .yarn/__virtual__/@rspack-core-virtual-f10b7c4cd3/0/cache/@rspack-core-npm-1.0.14-374d04781a-3743c2dd9e.zip/node_modules/@rspack/core/dist/index.js:17323:18Reproduce link
No response
Reproduce Steps
Provide a config that includes an undefined value in module.rules array and run a build.