RegExp.prototype.source getter called on non-RegExp object

[consense]

Issue type:

[ ] question
[ X ] bug report
[ ] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[ X ] postgres
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ ] latest
[ ] @next
[ X ] typeorm@0.2.9 (or put your version here)

Error doesnt appear in typeorm@0.2.8 and is thrown in versions typeorm@0.2.9 through to typeorm@0.2.12

Steps to reproduce or a small repository showing the problem:

     TypeError: RegExp.prototype.source getter called on non-RegExp object
      at RegExp.get source [as source] (<anonymous>)
      at RegExp.toString (<anonymous>)
      at isNaN (<anonymous>)
      at Function.OrmUtils.compare2Objects (src\util\OrmUtils.ts:171:13)
      at Function.OrmUtils.compare2Objects (src\util\OrmUtils.ts:236:31)
      at Function.OrmUtils.compare2Objects (src\util\OrmUtils.ts:236:31)
      at Function.OrmUtils.compare2Objects (src\util\OrmUtils.ts:236:31)
      at Function.OrmUtils.deepCompare (src\util\OrmUtils.ts:118:23)
      at Function.EntityMetadata.compareIds (src\metadata\EntityMetadata.ts:723:25)
      at EntityMetadata.compareEntities (src\metadata\EntityMetadata.ts:590:31)
      at \src\persistence\SubjectDatabaseEntityLoader.ts:126:81
      at Array.filter (<anonymous>)
      at SubjectDatabaseEntityLoader.findByPersistEntityLike (src\persistence\SubjectDatabaseEntityLoader.ts:119:30)
      at \src\persistence\SubjectDatabaseEntityLoader.ts:96:39
      at Array.forEach (<anonymous>)
      at SubjectDatabaseEntityLoader.<anonymous> (src\persistence\SubjectDatabaseEntityLoader.ts:95:22)
      at step (node_modules\typeorm\persistence\SubjectDatabaseEntityLoader.js:32:23)
      at Object.next (node_modules\typeorm\persistence\SubjectDatabaseEntityLoader.js:13:53)
      at fulfilled (node_modules\typeorm\persistence\SubjectDatabaseEntityLoader.js:4:58)
      at process._tickCallback (internal/process/next_tick.js:68:7)

Gladly tell me if you'd need more info - tbh I would be hard pressed to produce a minimal reproduction repo, but if you have any specific questions just shoot :-)

[Kononnable]

Yeah, I think we would need some way to reproduce that :)
Right now we know when bug was introduced(1 month period) but without way to reproduce it we won't be able to confirm any fixes or even if bug is in typeorm code.

[sam-hunt]

Just had this throw in typeorm@0.2.18. Also as yet unsure of the cause.

[tobyhinloopen]

@Kononnable I found a way to reproduce the error: Try to persist an object with a RegExp in one of the columns. Note that I do use a transformer to transform a regular expression into a string.

import { Entity, PrimaryGeneratedColumn } from "typeorm";
import { RegExpColumn } from "../../src/RegExpColumn";

@Entity()
export class Thing {
  @PrimaryGeneratedColumn()
  public id: number;

  @RegExpColumn()
  public foo: RegExp;
}

import { Column, ColumnOptions } from "typeorm";
import { RegExpStringTransformer } from "./RegExpStringTransformer";

export function RegExpColumn(opts: ColumnOptions = {}) {
  opts.type = String;
  opts.transformer = RegExpStringTransformer;
  return Column(opts)
}

export namespace RegExpStringTransformer {
  export function to(value: RegExp): string {
    return value.toString(); // <<< error is thrown here, since `value` is no longer a RegExp
  }

  export function from(value: string): RegExp {
    const match = value.match(/^\/(.*)\/(.*)$/);
    if (match) {
      const [, pattern, flags] = match;
      return new RegExp(pattern, flags);
    } else {
      throw new Error(`"${value}" is not a regular expression`);
    }
  }
}

test("entity with RegExpColumn stores regular expression", async function() {
  const thing = new Thing();
  thing.foo = /foo/i;
  const savedThing = await thingRepo.save(thing); // <<< Error here
  expect(savedThing.foo).toEqual(/foo/i);
  const storedThing = await thingRepo.findOne(savedThing.id);
  expect(storedThing.foo).toEqual(/foo/i);
});

Repo (exact commit): https://github.com/tobyhinloopen/bonaroo-reg-exp-column/tree/65f591bffe62cbf9bdabd84cf4fc6352a5ae6eb5

I've done hours of traversing through typeorm and SOMEWHERE inside TypeORM something replaces the native /foo/i regexp with a seemingly empty object with a RegExp constructor. I suspect something tries to clone the entity or entity's values, and the cloning "breaks" the RegExp object:

$ node
> foo = /foo/i
/foo/i
> bar = Object.create(foo);
RegExp {}
> bar.toString()
TypeError: RegExp.prototype.source getter called on non-RegExp object
    at RegExp.get source [as source] (<anonymous>)
    at RegExp.toString (<anonymous>)

$ node -v
v10.15.1

[tobyhinloopen]

Found the origin: OrmUtils.mergeDeep clones RegExp (and possibly other JS objects) incorrectly. This was last changed here:

c3ff3d3

[tobyhinloopen]

@consense @sam-hunt This PR should fix your problem: #5182