assert: add checkPrototype option for assert.deepStrictEqual()

[Trott]

Allow usage of assert.deepStrictEqual() without prototype checks.

Refs: #28011

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[Trott]

Seemed like a pretty good idea when we talked about it in #28011 but now that it's implemented, I wonder if we're trying to solve the wrong problem. People already have a way to do this: assert.deepEqual(). This doesn't really provide a smooth onramp to moving to assert.deepStrictEqual() since it won't work in older versions of Node.js. If people want strict comparisons, they can use Object.create() or Object.setPrototypeOf() or another mechanism to duplicate prototypes to their test results.

[Trott]

This doesn't really provide a smooth onramp to moving to assert.deepStrictEqual() since it won't work in older versions of Node.js.

Maybe a smooth-enough onramp might be to set .strict mode to cause deepEqual() to be the same as deepStrictEqual() but with this option set to false. That would be a breaking change so would land in 13.x at the earliest. This would allow packages like esprima to use .strict mode without needing to modify the tests (beyond specifying .strict). Packages that only care about 13.x and newer could use .strict. Packages that need to support 12.x can do that and add this option explicitly. If we backport this to 10.x, people can use the option there too. For earlier versions, people can guard with assert = assert.strict || assert to keep current behavior in 8.x and earlier. The option in 8.x and earlier will result in [object Object] messages when AssertionErrors occur, unless additional precautions are taken. But that seems manageable or even ignorable in many cases as 8.x will be EOL in four months.

Interested in @BridgeAR's thoughts on the above.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/25290/

[Trott]

Maybe a smooth-enough onramp might be to set .strict mode to cause deepEqual() to be the same as deepStrictEqual() but with this option set to false.

Although I guess that could be a foot-gun for current .strict users and also a surprise for new adopters.

[Trott]

@nodejs/assert

[BridgeAR]

I would rather not add this option. Instead, I would favor rewriting assert to a class where it's possible to set options. One of those could be to deactivate the prototype check.
We just have to make sure to keep the assert module backwards compatible.