ncc-bug-1

Test environment:

@vercel/ncc, version: 0.24.1

MacOS 10.15.6 with Node v12.16.2

Windows 10, version 19.09 build 18363.1082, with Node v12.16.3

Created for filing bug with vercel/ncc

We are fans on ncc by Vercel and think it is a wonderful tool. When working on a multi-os compatible Node.js application we ran across a strange bug and needed to create a reproducible repo for it. The bug in quest is related to file system based imports. We ran into this while building an application that used knex and have thus used it here.

This code has been tested on Linux, MacOS, and Windows. The bug in question. only affects Windows environments for reasons unclear.

Reproducing the bug

npm run ncc
node dist/index.js

On regular (non-bug) systems this will result in:

$node dist/index.js

Knex type is: function

On Windows systems this bug results in:

$ npm run exec

> ncc-bug-1@0.0.0 exec C:\code\urbdyn\ncc-bug-1
> node dist/index.js

C:\code\urbdyn\ncc-bug-1\dist\index.js:56172
  const newKnex = makeKnex(new Dialect(config));
                           ^

TypeError: Dialect is not a constructor
    at Knex (C:\code\urbdyn\ncc-bug-1\dist\index.js:56172:28)
    at doTest (C:\code\urbdyn\ncc-bug-1\dist\index.js:146952:34)
    at Module.63899 (C:\code\urbdyn\ncc-bug-1\dist\index.js:146969:1)
    at __webpack_require__ (C:\code\urbdyn\ncc-bug-1\dist\index.js:147637:43)
    at C:\code\urbdyn\ncc-bug-1\dist\index.js:147706:18
    at Object.<anonymous> (C:\code\urbdyn\ncc-bug-1\dist\index.js:147707:12)
    at Module._compile (internal/modules/cjs/loader.js:1133:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1153:10)
    at Module.load (internal/modules/cjs/loader.js:977:32)
    at Function.Module._load (internal/modules/cjs/loader.js:877:14)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! ncc-bug-1@0.0.0 exec: `node dist/index.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the ncc-bug-1@0.0.0 exec script.
npm ERR! This is probably not a problem with npm. There is likely additional 

Initial triage

Based on a quick review of the code, we find the following difference. For a well working ncc output we get the results in dist-macos/index.js starting on line 56107

/***/ 71330:
/***/ ((module, __unused_webpack_exports, __webpack_require__) => {

function __ncc_wildcard$0 (arg) {
  if (arg === "mssql") return __webpack_require__(19427);
  else if (arg === "mysql") return __webpack_require__(75941);
  else if (arg === "mysql2") return __webpack_require__(17653);
  else if (arg === "oracle") return __webpack_require__(9051);
  else if (arg === "oracledb") return __webpack_require__(25310);
  else if (arg === "postgres") return __webpack_require__(64482);
  else if (arg === "redshift") return __webpack_require__(97332);
  else if (arg === "sqlite3") return __webpack_require__(85370);
}

For a buggy ncc output on windows we get the results in dist-windows/index.js starting on line 56107

/***/ 71330:
/***/ ((module, __unused_webpack_exports, __webpack_require__) => {

function __ncc_wildcard$0 (arg) {
  if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(19427);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(75941);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(17653);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(9051);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(25310);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(64482);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(97332);
  else if (arg === "C:/code/urbdyn/ncc-bug-1/node_modules/knex/lib/dialects/") return __webpack_require__(85370);
}