tools,test: enforce deepStrictEqual over deepEqual #6213

Trott · 2016-04-15T07:05:58Z

Checklist

tests and code linting passes
the commit message follows commit guidelines

Affected core subsystem(s)

tools, test, benchmark

Description of change

Introduce a lint rule that enforces use of assert.deepStrictEqual()
over assert.deepEqual().

This is a proof of concept inspired by @Fishrock123 wondering in #6196 (comment):

We could make a lint rule that requires strict assertions for the tests, but I feel people may be opposed to that?

I like it, but (like Fishrock123) I don't know if others will feel the same.

If this is deemed a good idea, it can optionally evolve from no-deepEqual to something that flags all non-strict assertions, perhaps only in the tests. Not going to bother, though, if there isn't consensus on this.

bnoordhuis · 2016-04-15T07:20:35Z

test/parallel/test-buffer-alloc.js

 Buffer.from(expected));
- assert.deepEqual(Buffer.from('__--_--_--__', 'base64'),
+ assert.deepStrictEqual(Buffer.from('__--_--_--__', 'base64'),
 Buffer.from(expected));


Can you line up the arguments here?

Fishrock123 · 2016-04-15T14:24:06Z

Should we also make assert only importable as assert?

Also, is it possible for the rule to check require('assert').deepEqual()?

Sidenote: while deepEqual() is the most egregious and easiest to mess up, I think we should also discuss not using assert(), assert.equal(), etc. Perhaps in another thread though.

jasnell · 2016-04-15T16:43:35Z

I can foresee cases where enforcing this rule strictly could cause issues but turning the rule off for individual tests that require lenient handling makes sense... so +1. Haven't reviewed the changes so not giving a LGTM yet.

Trott · 2016-04-18T20:01:17Z

Fixed all of @bnoordhuis's nits, rebased, force pushed.

cjihrig · 2016-04-18T20:08:51Z

LGTM

jasnell · 2016-04-18T21:40:04Z

LGTM

jasnell · 2016-04-19T00:00:32Z

CI: https://ci.nodejs.org/job/node-test-pull-request/2306/

jasnell · 2016-04-19T04:43:32Z

@bnoordhuis ... can you take another look?
@Trott ... looks like this needs a rebase

Trott · 2016-04-19T05:57:58Z

@jasnell: Rebased and force pushed.

Trott · 2016-04-19T06:19:18Z

@Fishrock123 asked:

Should we also make assert only importable as assert?

It's a good question and something I thought about when I wrote the rule.

The answer is yes, but I'd be -0.5 on something like that. There are basically two reasons.

First, it won't stop people from re-assigning:

const assert = require('assert');
const a = assert;
a.deepEqual(foo, bar);

So we're going to have an imperfect rule still. And if we're going to have an imperfect rule, I'd rather have it be simple and imperfect than convoluted and imperfect.

Second, you either have to enforce the identifier name in this rule or you have to create a separate rule to enforce it. If you put it in this rule, it's a bit of scope creep that doesn't quite pass the smell test. This rule is about avoiding deepEqual(). Enforcing that the name of the identifier be assert violates the principle of least astonishment. Ideally, what the rule does should be obvious and unsurprising, at least as much as is feasible. On the other hand, if you make it a separate rule to enforce the identifier name, it's hard to explain why that rule exists. "Oh, it exists because this other rule will miss stuff if the identifier isn't what that rule expects." I don't know, that just doesn't seem to cut it. I'd rather see attempts made to improve the deepEqual() rule so it doesn't need to assume anything about the identifier, although I don't know if that's possible, or at least if it's possible without making the rule very complicated.

Anyway, that was my thinking for not doing that. I'm not 100% opposed, but I am predisposed to be skeptical of going that route. Sorry for the longwinded response to a simple question.
¯_(ツ)_/¯

Trott · 2016-04-19T06:33:47Z

@Fishrock123 asked:

Also, is it possible for the rule to check require('assert').deepEqual()?

Yes. There aren't any instances of that in the current code base. Future enhancement after this bakes in on master for a while (and if it can be done without adding too much complexity to the rule)? Or maybe something to discuss in another thread along with other non-strict assert functions we may want to avoid?

Trott · 2016-04-19T06:52:18Z

Another CI, since I rebased and force pushed: https://ci.nodejs.org/job/node-test-pull-request/2310/

EDIT: Well, that certainly didn't go well...

EDIT 2: I'm guessing e38bade is the source of the trouble. We have to modify the tests so that the expected value does not inherit from Object.prototype. This is a good thing as the tests will now make sure that the code in the commit is having the desired effect downstream.

EDIT 3: dba245f too.

Trott · 2016-04-19T22:50:17Z

OK, all fixed up. These changes uncovered a bug (or at least I consider it a bug) that is now fixed (or reduced, in any event, if it isn't fixed in all scenarios) in the first commit.

If you looked at it before, it would be great if you could look again because there are some significant changes.

@cjihrig @jasnell @bnoordhuis @mscdex @Fishrock123 @nodejs/testing

Trott · 2016-04-19T22:56:38Z

CI: https://ci.nodejs.org/job/node-test-pull-request/2329/

jasnell · 2016-04-19T23:21:41Z

@Trott ... that fix works for me.

Trott · 2016-04-20T04:25:16Z

CI is good except for one buildbot failure.

jasnell · 2016-04-20T16:13:17Z

@Trott... Looks like this needs a quick rebase before landing.

In preparation for a lint rule that will enforce assert.deepStrictEqual() over assert.deepEqual(), change tests and benchmarks accordingly. For tests and benchmarks that are testing or benchmarking assert.deepEqual() itself, apply a comment to ignore the upcoming rule.

Introduce a lint rule that enforces use of `assert.deepStrictEqual()` over `assert.deepEqual()`.

Trott · 2016-04-20T19:32:33Z

@jasnell Rebased and force-pushed.

Added labels to not land on v4 or v5 because some changes depend on previous semver major changes.

New CI: https://ci.nodejs.org/job/node-test-pull-request/2347/

Trott · 2016-04-20T22:03:38Z

Only failure in Ci is a known flaky test.

jasnell · 2016-04-20T22:14:35Z

LGTM

Trott · 2016-04-22T03:31:33Z

Last (or hopefully last) call for additional reviews or objections. If no objections, I'll land this at or soon after 9PM UTC (that's 2PM PDT) tomorrow (Friday).

Trott · 2016-04-22T03:35:46Z

Whoops, meant to do a /cc @nodejs/collaborators on that last comment. Which, for the benefit of those only getting this via email notification, was:

Last (or hopefully last) call for additional reviews or objections. If no objections, I'll land this at or soon after 9PM UTC (that's 2PM PDT) tomorrow (Friday).

In preparation for a lint rule that will enforce assert.deepStrictEqual() over assert.deepEqual(), change tests and benchmarks accordingly. For tests and benchmarks that are testing or benchmarking assert.deepEqual() itself, apply a comment to ignore the upcoming rule. PR-URL: nodejs#6213 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Introduce a lint rule that enforces use of `assert.deepStrictEqual()` over `assert.deepEqual()`. PR-URL: nodejs#6213 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Trott · 2016-04-22T21:40:42Z

Landed in a7335bd and e84c693

In preparation for a lint rule that will enforce assert.deepStrictEqual() over assert.deepEqual(), change tests and benchmarks accordingly. For tests and benchmarks that are testing or benchmarking assert.deepEqual() itself, apply a comment to ignore the upcoming rule. PR-URL: nodejs#6213 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Introduce a lint rule that enforces use of `assert.deepStrictEqual()` over `assert.deepEqual()`. PR-URL: nodejs#6213 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

In preparation for a lint rule that will enforce assert.deepStrictEqual() over assert.deepEqual(), change tests and benchmarks accordingly. For tests and benchmarks that are testing or benchmarking assert.deepEqual() itself, apply a comment to ignore the upcoming rule. PR-URL: #6213 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Introduce a lint rule that enforces use of `assert.deepStrictEqual()` over `assert.deepEqual()`. PR-URL: #6213 Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Trott added test Issues and PRs related to the tests. benchmark Issues and PRs related to the benchmark subsystem. tools Issues and PRs related to the tools directory. labels Apr 15, 2016

bnoordhuis reviewed Apr 15, 2016
View reviewed changes

Trott force-pushed the no-deepEqual branch 2 times, most recently from b54ca5d to b0aaef6 Compare April 18, 2016 20:00

Trott force-pushed the no-deepEqual branch from b0aaef6 to aa52e6e Compare April 19, 2016 05:57

Trott mentioned this pull request Apr 19, 2016

querystring: don't inherit from Object.prototype #6055

Merged

3 tasks

Trott force-pushed the no-deepEqual branch from aa52e6e to 8ef635e Compare April 19, 2016 22:47

tools: enforce deepStrictEqual over deepEqual

f0d728c

Introduce a lint rule that enforces use of `assert.deepStrictEqual()` over `assert.deepEqual()`.

Trott force-pushed the no-deepEqual branch from 8ef635e to f0d728c Compare April 20, 2016 19:30

Trott added dont-land-on-v4.x labels Apr 20, 2016

Trott closed this Apr 22, 2016

Trott deleted the no-deepEqual branch January 13, 2022 22:43

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tools,test: enforce deepStrictEqual over deepEqual #6213

tools,test: enforce deepStrictEqual over deepEqual #6213

Trott commented Apr 15, 2016

bnoordhuis Apr 15, 2016

Fishrock123 commented Apr 15, 2016

jasnell commented Apr 15, 2016

Trott commented Apr 18, 2016

cjihrig commented Apr 18, 2016

jasnell commented Apr 18, 2016

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tools,test: enforce deepStrictEqual over deepEqual #6213

tools,test: enforce deepStrictEqual over deepEqual #6213

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Trott commented Apr 15, 2016

Checklist

Affected core subsystem(s)

Description of change

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