fix: time.Time rendering in the diff returned by error message

[ccoVeille]

Summary

Improve formatting when dealing with time.Time now we vendored gospew

Changes

Now, go-spew is vendored, we can fix old issues we had.

We can fix the representation of time.Time in gospew

And remove the imperfect fix we had in place.

Motivation

#895 was created by @luan to solve some legitimate issues. It was released with v1.6.0 on May 29, 2020

• Disable using Stringer/error interfaces for diffing #895

But unfortunately, the changes lead to an issue with the way time.Time are rendered. So #989 was opened on Aug 1, 2020 by @AlekSi

• time.Time comparison produces non-helpful diff #989

The issue was somehow fixed with #1072 by @HaraldNordgren

• Make sure time.Time comparison produces a helpful diff. closes #989 #1072

#1072 was merged in Apr 27, 2021 (but only released in Mar 1, 2024 with v1.7.1 )

Unfortunately, the fix was incomplete, as it was working only for first level, so #1078 was opened on May 22, 2021 by @shawc71

• Diffs on structs with nested time.Time objects produce hard to read diffs #1078

#1079 was opened by @shawc71 on May 22, 2021 to try to fix the issue

• Make spew config selection configurable to allow for helpful diffs on time.Time objects nested in structs. #1079

But it was never merged, as the solution was also imperfect, and because they were no solution inside testify to fix this

So #1078 was left open until now.

Related issues

• Related to go-spew vendoring #1826
• Closes Make spew config selection configurable to allow for helpful diffs on time.Time objects nested in structs. #1079
• Closes Diffs on structs with nested time.Time objects produce hard to read diffs #1078

[ccoVeille]

@brackendawson please review, it's ready.

I'm facing this issue with testify for ages, I cannot wait to see it fixed 😬

[fredbi]

@ccoVeille I found your PR definitely interesting but perhaps lacking a few things.
You may find an alternate implementation there go-openapi#27
The main differences are:

• does not use type string representation, but type convertibility to time
• does not sort using the string representation (time.Time does NOT implement sort.Interface), but uses time.Time.Compare instead
• more tests with embedded types, private fields, pointers, nil values etc

Could be interesting to exchange our views

[ccoVeille]

Thanks @fredbi. I will take a look.

I saw the PRs you made in the last days.

I agree with you about the string sort that can lead to problem when comparing for example 999-12-31 and 1000-01-01

I'll review the PR in your fork also

[Copilot]

Pull request overview

This PR improves time.Time formatting in assertion diffs by leveraging the newly vendored internal spew package, removing the prior special-casing in assert.diff and enabling readable time.Time output while keeping method calls disabled for other types.

Changes:

• Added EnableTimeStringer to internal/spew.ConfigState and used it to selectively call String() for time.Time.
• Updated assert diffing to rely on the new spew behavior instead of a dedicated time.Time branch/config.
• Added/expanded tests covering time.Time diff output at top-level and within structs.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
internal/spew/config.go	Adds EnableTimeStringer config knob to selectively allow time.Time.String() even when methods are otherwise disabled.
internal/spew/format.go	Uses EnableTimeStringer to allow method handling for time.Time during formatting.
internal/spew/dump.go	Uses EnableTimeStringer to allow method handling for time.Time during dumping.
internal/spew/common.go	Attempts to adjust sorting behavior (currently incorrectly) for time.Time.
internal/spew/spew_test.go	Adds test cases validating time.Time formatting with/without the new config flag.
assert/assertions.go	Removes the old time.Time-specific diff special-case and enables EnableTimeStringer on the shared spew config.
assert/assertions_test.go	Adds a regression test for diffing structs containing time.Time.

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[ccoVeille]

Copilot provided the same feedback as you @fredbi

This time I got it, haha

[fredbi]

Copilot provided the same feedback as you @fredbi

This time I got it, haha

Should I feel flattered? Mmh not so sure :)
Anyway you may always take a look at the implementation at github.com/go-openapi/testify (v2). This part has been merged long ago. All further improvements there are of course welcome.

[ccoVeille]

Copilot provided the same feedback as you @fredbi

This time I got it, haha

Should I feel flattered? Mmh not so sure :)

Haha. It's simply that:

• I haven't check last time
• Copilot spotted the exact lines that are bad. It was easier to figure out what was the problem.

Anyway you may always take a look at the implementation at github.com/go-openapi/testify (v2). This part has been merged long ago. All further improvements there are of course welcome.

I'm already looking at it.