Bug - Documentation framework - syntax errors crash server and does not provide any valuable debug info

[mcoker]

A way to trigger it is to do something like put 2 (or more than 1) colons in a custom property declaration or remove the trailing semicolon from a custom property declaration. Eg,

// valid
.some-selector {
  --bg: red;
  --color: white;
}

// invalid
.some-selector {
  --bg: red // missing trailing semicolon
  --color:: white; // more than 1 colon
}

It will give this error

node:events:491
      throw er; // Unhandled 'error' event
      ^

TypeError: Cannot read properties of undefined (reading 'postcss')
    at Object.loader (/Users/cmichael/repos/patternfly/node_modules/@patternfly/documentation-framework/node_modules/postcss-loader/dist/index.js:103:35)
Emitted 'error' event on Domain instance at:
    at emit (node:internal/process/promises:147:33)
    at processPromiseRejections (node:internal/process/promises:283:27)
    at process.processTicksAndRejections (node:internal/process/task_queues:96:32)

Node.js v18.16.0
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.