assert: refactor AssertionError properties #25250

BridgeAR · 2018-12-28T17:52:27Z

When inspecting an AssertionError the actual and expected properties would also show up inspected (due to another recent change that made sure that extra properties on errors will always be visible).

This is not really very user friendly since we already print something in the error message and showing the values again, duplicates the output. Another alternative to this would be to use a custom inspection function for AssertionError but I believe just moving these two properties behind getters already solved the problem well enough while keeping the other properties visible to the user.

The other commit fixes a test case.

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

The `actual` and `expected` properties on an instance of `AssertionError` is now a getter to prevent inspecting these when inspecting the error. These values will be visible in the error message and showing them otherwise would decrease the readability of the error.

One test did not cause an assertion. By changing the test to use `assert.throws()` all tests have to throw, otherwise the test will fail.

nodejs-github-bot · 2018-12-28T17:52:29Z

@BridgeAR build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/2088/pipeline

test/parallel/test-assert.js

Trott

Test change/fix LGTM. No comment on the behavior change of not inspecting expected/actual. I'd need to think more on the ramifications there. (Maybe a before/after comparison to show the difference would be illuminating.)

BridgeAR · 2018-12-28T19:11:29Z

Before:

> assert.deepStrictEqual(Array(25).fill(10), 2)
{ [AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
+ actual - expected ... Lines skipped

+ [
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
...
- 2
...]
  generatedMessage: true,
  name: 'AssertionError [ERR_ASSERTION]',
  code: 'ERR_ASSERTION',
  actual:
   [ 10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10,
     10 ],
  expected: 2,
  operator: 'deepStrictEqual' }

After

assert.deepStrictEqual(Array(25).fill(10), 2)
{ [AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
+ actual - expected ... Lines skipped

+ [
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
...
- 2
...]
  generatedMessage: true,
  name: 'AssertionError [ERR_ASSERTION]',
  code: 'ERR_ASSERTION',
  actual: [Getter/Setter],
  expected: [Getter/Setter],
  operator: 'deepStrictEqual' }

cjihrig · 2018-12-28T21:12:43Z

  actual: [Getter/Setter],
  expected: [Getter/Setter],

That output might be shorter, but I don't think it's helpful at all.

BridgeAR · 2018-12-28T21:24:34Z

@cjihrig

That output might be shorter, but I don't think it's helpful at all.

That output itself is only meant so the user known it's possible to access those properties. As I outlined above, these entries were not inspected at all until recently. Now that the extra properties are inspected by default we'd duplicate information and hide the actual error message above other information. That's why I choose this as a good middle ground.

Do you have a better alternative? (It's still possible to use a custom inspection function as well)

cjihrig · 2018-12-28T21:27:58Z

I can imagine the Getter/Setter output being especially misleading to newcomers. A custom inspection function that restores the old behavior should be fine.

BridgeAR · 2018-12-28T22:03:59Z

@cjihrig yeah, that output is indeed subpar. I believe I found another good way to display this:

assert.deepStrictEqual(Array(25).fill(10), 2)
{ [AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
+ actual - expected ... Lines skipped

+ [
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
+   10,
...
- 2
...]
  generatedMessage: true,
  name: 'AssertionError [ERR_ASSERTION]',
  code: 'ERR_ASSERTION',
  actual: [Array],
  expected: 2,
  operator: 'deepStrictEqual' }

lib/internal/assert.js

addaleax · 2019-01-07T23:24:50Z

CI: https://ci.nodejs.org/job/node-test-pull-request/19982/ ✔️

Co-Authored-By: BridgeAR <[email protected]>

BridgeAR · 2019-01-09T01:40:25Z

I just started the lite CI because there's only a typo fix and the last full CI is green.

~~Lite-CI https://ci.nodejs.org/job/node-test-pull-request-lite-pipeline/2193/~~
Lite-CI https://ci.nodejs.org/job/node-test-pull-request-lite-pipeline/2201/

BridgeAR · 2019-01-10T02:27:40Z

Landed in dfaa61f, 8c0290e 🎉

Thanks everyone for the reviews.

The `actual` and `expected` properties on an instance of `AssertionError` is now a getter to prevent inspecting these when inspecting the error. These values will be visible in the error message and showing them otherwise would decrease the readability of the error. PR-URL: nodejs#25250 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

One test did not cause an assertion. By changing the test to use `assert.throws()` all tests have to throw, otherwise the test will fail. PR-URL: nodejs#25250 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

The `actual` and `expected` properties on an instance of `AssertionError` is now a getter to prevent inspecting these when inspecting the error. These values will be visible in the error message and showing them otherwise would decrease the readability of the error. PR-URL: #25250 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

One test did not cause an assertion. By changing the test to use `assert.throws()` all tests have to throw, otherwise the test will fail. PR-URL: #25250 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

The `actual` and `expected` properties on an instance of `AssertionError` is now a getter to prevent inspecting these when inspecting the error. These values will be visible in the error message and showing them otherwise would decrease the readability of the error. PR-URL: nodejs#25250 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

One test did not cause an assertion. By changing the test to use `assert.throws()` all tests have to throw, otherwise the test will fail. PR-URL: nodejs#25250 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

BridgeAR added 2 commits December 28, 2018 18:45

test: fix failing assertion

d92a714

One test did not cause an assertion. By changing the test to use `assert.throws()` all tests have to throw, otherwise the test will fail.

nodejs-github-bot added the assert Issues and PRs related to the assert subsystem. label Dec 28, 2018

Trott reviewed Dec 28, 2018

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Trott reviewed Dec 28, 2018

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BridgeAR added 2 commits December 29, 2018 00:02

fixup: use custom inspect function to minimize input inspection

bc2ccc2

fixup: move comment

06e5388

addaleax approved these changes Jan 7, 2019

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lib/internal/assert.js Outdated Show resolved Hide resolved

jasnell approved these changes Jan 8, 2019

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fixup: fix typo

0f7ff0e

Co-Authored-By: BridgeAR <[email protected]>

BridgeAR added the author ready PRs that have at least one approval, no pending requests for changes, and a CI started. label Jan 9, 2019

BridgeAR closed this Jan 10, 2019

BridgeAR mentioned this pull request Jan 16, 2019

v11.7.0 proposal #25537

Merged

MylesBorins mentioned this pull request Jan 24, 2019

v11.8.0 proposal #25687

Merged

BridgeAR deleted the minor-assert-things branch January 20, 2020 11:51

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assert: refactor AssertionError properties #25250

assert: refactor AssertionError properties #25250

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assert: refactor AssertionError properties #25250

assert: refactor AssertionError properties #25250

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