feat: join error

[Gogomoe]

What's changed and what's your intention?

resolve #22
eris.Join(err...) almost is eris.Wrap(errors.Join(err...), "join error")
Implementing and testing the format is a bit hard.
the format looks like:

// no trace text
code(internal) outer wrap: code(unknown) join error
0>	fmt error
1>	code(internal) wrap1: code(internal) wrap2: external
2>	code(unknown) eris error

// trace text
code(internal) outer wrap
	eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:22
code(unknown) join error
	eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:22
	eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:17
0>	fmt error
1>	code(internal) wrap1
		eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:19
	code(internal) wrap2
		eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:19
		eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:19
	external
2>	code(unknown) eris error
		eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:20

// no trace json
{
	"externals": [
		{
			"external": "fmt error"
		},
		{
			"external": "external",
			"root": {
				"code": "internal",
				"message": "wrap2"
			},
			"wrap": [
				{
					"code": "internal",
					"message": "wrap1"
				}
			]
		},
		{
			"root": {
				"code": "unknown",
				"message": "eris error"
			}
		}
	],
	"root": {
		"code": "unknown",
		"message": "join error"
	},
	"wrap": [
		{
			"code": "internal",
			"message": "outer wrap"
		}
	]
}

// trace json
{
	"externals": [
		{
			"external": "fmt error"
		},
		{
			"external": "external",
			"root": {
				"code": "internal",
				"message": "wrap2",
				"stack": [
					"eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:19",
					"eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:19"
				]
			},
			"wrap": [
				{
					"code": "internal",
					"message": "wrap1",
					"stack": "eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:19"
				}
			]
		},
		{
			"root": {
				"code": "unknown",
				"message": "eris error",
				"stack": [
					"eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:20"
				]
			}
		}
	],
	"root": {
		"code": "unknown",
		"message": "join error",
		"stack": [
			"eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:22",
			"eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:17"
		]
	},
	"wrap": [
		{
			"code": "internal",
			"message": "outer wrap",
			"stack": "eris_test.TestName:/Users/gogo/workspace/eris/a_test.go:22"
		}
	]
}

Checklist

• I have written the necessary docs and comments
• I have added necessary unit tests and integration tests

Refer to a related PR or issue link (optional)

Close #22

[codecov]

Codecov Report

Attention: Patch coverage is 91.89189% with 3 lines in your changes missing coverage. Please review.

Project coverage is 86.51%. Comparing base (e59a5ad) to head (4812207).

Files	Patch %	Lines
format.go	90.62%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #26      +/-   ##
==========================================
+ Coverage   86.33%   86.51%   +0.18%     
==========================================
  Files           4        4              
  Lines         556      586      +30     
==========================================
+ Hits          480      507      +27     
- Misses         72       73       +1     
- Partials        4        6       +2     

Flag	Coverage Δ
unittests	86.51% <91.89%> (+0.18%)	⬆️

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[wjf3121]

This will break eris.Is's behavior, which I'm not so sure.

Caller can be easily mistaken and make the wrong assumption.

[CAJan93]

I think we should for sure test that eris.Is still works with this implementation

First simple test in #28 shows that it still seems to work. In the end we inherit the behaviour of errors.Join

I did not want to push into your branch, that is why I created the tiny PR @Gogomoe

[Gogomoe]

Sorry i forget to reply the comment. The eris.is and as are implemented in #27. I also added more testcases to cover the join error

[CAJan93]

@Gogomoe out of curiosity. What would you like to use eris.Join for? To me the idiomatic way to handle go errors is

value, err := someFunc(input)
if err != nil {
   // wrap err and return
}

When do we want to join? The only things that I can think about are

• validating something, e.g. user input, and returning an all the found errors
• doing multiple tasks concurrently, waiting until all tasks are done, and then joining the errors.

[Gogomoe]

@Gogomoe out of curiosity. What would you like to use eris.Join for? To me the idiomatic way to handle go errors is

Another situation is retry an action for mutiple times. It's a common pattern used in our code base. I dont' want to ignore any error when all retry fails. Currently, we use errors.join in this case. You can check the use case by searching it in our code base

[wjf3121]

LGTM!

[wjf3121]

nit: I suppose this can be t.Errorf as we can still check the rest of the wrapError in the loop.

[Gogomoe]

I copied the wrapMap section from other test cases. Leet's keep it 🤪

[Gogomoe]

I plan to merge this PR tomorrow. @CAJan93 Do you have more opinions about this PR?