Mikro ORM Reproduction for #676

1. Clone
2. Run yarn
3. Create a database on your local Postgres called mikro_orm_test_gh_676.
4. Run yarn start

Expected Output:

yarn start
yarn run v1.22.4
$ yarn build && node dist/index
$ webpack --config webpack.config.js
Hash: f682753770a1775d9bd9
Version: webpack 4.43.0
Time: 6222ms
Built at: 07/22/2020 11:28:29 AM
                                    Asset       Size  Chunks             Chunk Names
        ../lib/src/entities/location.d.ts  291 bytes          [emitted]
    ../lib/src/entities/location.d.ts.map  353 bytes          [emitted]
    ../lib/src/entities/organisation.d.ts  355 bytes          [emitted]
../lib/src/entities/organisation.d.ts.map  421 bytes          [emitted]
                    ../lib/src/index.d.ts   46 bytes          [emitted]
                ../lib/src/index.d.ts.map  107 bytes          [emitted]
                                 index.js   2.61 MiB    main  [emitted]  main
Entrypoint main = index.js
[./node_modules/@mikro-orm/core/metadata sync recursive] ./node_modules/@mikro-orm/core/metadata sync 160 bytes {main} [built]
[./node_modules/@mikro-orm/core/utils sync recursive] ./node_modules/@mikro-orm/core/utils sync 160 bytes {main} [built]
[./node_modules/@mikro-orm/core/utils sync recursive ^.*\/package\.json$] ./node_modules/@mikro-orm/core/utils sync ^.*\/package\.json$ 160 bytes {main} [built]
[./src/entities/location.ts] 1.43 KiB {main} [built]
[./src/entities/organisation.ts] 1.84 KiB {main} [built]
[./src/index.ts] 1.36 KiB {main} [built]
[assert] external "assert" 42 bytes {main} [built]
[crypto] external "crypto" 42 bytes {main} [built]
[domain] external "domain" 42 bytes {main} [built]
[fs] external "fs" 42 bytes {main} [built]
[module] external "module" 42 bytes {main} [built]
[path] external "path" 42 bytes {main} [built]
[stream] external "stream" 42 bytes {main} [built]
[url] external "url" 42 bytes {main} [built]
[util] external "util" 42 bytes {main} [built]
    + 457 hidden modules

WARNING in ./node_modules/@mikro-orm/core/utils/ConfigurationLoader.js 56:29-50
Critical dependency: the request of a dependency is an expression
 @ ./node_modules/@mikro-orm/core/utils/index.js
 @ ./node_modules/@mikro-orm/core/index.js
 @ ./src/index.ts

WARNING in ./node_modules/@mikro-orm/core/metadata/JavaScriptMetadataProvider.js 48:27-40
Critical dependency: the request of a dependency is an expression
 @ ./node_modules/@mikro-orm/core/metadata/index.js
 @ ./node_modules/@mikro-orm/core/index.js
 @ ./src/index.ts

WARNING in ./node_modules/@mikro-orm/core/utils/Utils.js 360:16-34
require.extensions is not supported by webpack. Use a loader instead.
 @ ./node_modules/@mikro-orm/core/utils/index.js 16:13-31
 @ ./node_modules/@mikro-orm/core/index.js
 @ ./src/index.ts

WARNING in ./node_modules/@mikro-orm/core/utils/Utils.js 360:40-58
require.extensions is not supported by webpack. Use a loader instead.
 @ ./node_modules/@mikro-orm/core/utils/index.js 16:13-31
 @ ./node_modules/@mikro-orm/core/index.js
 @ ./src/index.ts
Running init
MikroORM.init() took 1.163 seconds.
Adding new organisation...
TypeError: Cannot read property '__meta' of undefined
    at new Reference (webpack:///./node_modules/@mikro-orm/core/entity/Reference.js?:10:17)
    at Function.create (webpack:///./node_modules/@mikro-orm/core/entity/Reference.js?:29:16)
    at Function.wrapReference (webpack:///./node_modules/@mikro-orm/core/utils/Utils.js?:409:39)
    at Organisation.set [as location] (webpack:///./node_modules/@mikro-orm/core/entity/EntityHelper.js?:99:56)
    at UnitOfWork.fixMissingReference (/Users/kevin/development/mikro-676/node_modules/@mikro-orm/core/unit-of-work/UnitOfWork.js:376:31)
    at UnitOfWork.cascadeReference (/Users/kevin/development/mikro-676/node_modules/@mikro-orm/core/unit-of-work/UnitOfWork.js:325:14)
    at UnitOfWork.cascade (/Users/kevin/development/mikro-676/node_modules/@mikro-orm/core/unit-of-work/UnitOfWork.js:321:18)
    at UnitOfWork.persist (/Users/kevin/development/mikro-676/node_modules/@mikro-orm/core/unit-of-work/UnitOfWork.js:110:14)
    at SqlEntityManager.persist (/Users/kevin/development/mikro-676/node_modules/@mikro-orm/core/EntityManager.js:307:34)
    at SqlEntityManager.persistAndFlush (/Users/kevin/development/mikro-676/node_modules/@mikro-orm/core/EntityManager.js:316:20)
error Command failed with exit code 1.

Profiling

Because MikroORM.init is taking quite a while, I've added 0x to profile what's taking so long. It looks like about half the time in init is spent in highlight.js, while the other half is spent getting a database connection, and the rest is not worth optimising because it's so small.

To run profiling locally after doing the steps above, run yarn profile. This should run then generate and open a flamegraph in your browser.

Here's an example flame graph.