NextJS 12 Runtime Crash - SyntaxError: Unexpected token ')' - next.js

Question

Im having an issue that I first saw after the release of NextJS 12 and im still seeing now with NextJS 12.0.8. It's completely stopping me from upgrading from version 11.
Essentially my application will build fine, no errors, and the server will start, but the second I make the first request to it, it trips over and I get the following highly unhelpful error
at Object.compileFunction (node:vm:352:18)
at wrapSafe (node:internal/modules/cjs/loader:1031:15)
at Module._compile (node:internal/modules/cjs/loader:1065:27)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
at Module.load (node:internal/modules/cjs/loader:981:32)
at Function.Module._load (node:internal/modules/cjs/loader:822:12)
at Module.require (node:internal/modules/cjs/loader:1005:19)
at require (node:internal/modules/cjs/helpers:102:18)
at Object.__webpack_require__.f.require (/app/.next/server/webpack-runtime.js:143:28)
at /app/.next/server/webpack-runtime.js:70:40
/app/.next/server/chunks/6859.js:135
/***/ }),
^
SyntaxError: Unexpected token ')'
at Object.compileFunction (node:vm:352:18)
at wrapSafe (node:internal/modules/cjs/loader:1031:15)
at Module._compile (node:internal/modules/cjs/loader:1065:27)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
at Module.load (node:internal/modules/cjs/loader:981:32)
at Function.Module._load (node:internal/modules/cjs/loader:822:12)
at Module.require (node:internal/modules/cjs/loader:1005:19)
at require (node:internal/modules/cjs/helpers:102:18)
at Object.__webpack_require__.f.require (/app/.next/server/webpack-runtime.js:143:28)
at /app/.next/server/webpack-runtime.js:70:40
The problem seems to be running on Alpine linux as I can perform a production build locally, then run it with no issues However after building my production docker container and deploying it, I see a white screen, with this error in the console.
Googling this has come up with nothing, checking the source at that point reveals nothing interesting to me.
My app has been working fine on Next JS 11, but upgrading to 12 blows up. I see nothing in the docs about needing to do anything different with regards to docker or alpine linux.
Can any one help?

Answer 1

So the problem was due to an internal cleaning process we run and a change in the way Next 12 prints the source map declarations.
Basically, the sourcemap definition was on the same line as the closing bracket, whereas it was on a new line previously.
More info here: https://github.com/vercel/next.js/issues/33241#issuecomment-1013580180