Fix Golang pattern validation with regex fails on commas #20079

[mlebihan]

In a struct, for a type: string accompanied by a pattern, these generated Go directives are corrected:

json:"creditCard,omitempty" validate:"regexp=^4[0-9]{3}\\s[0-9]{4}\\s[0-9]{4}\\s[0-9]{4}$"` 

Test cases added

18 new regular expressions has been taken for test cases, from an SAP help page.

A go test has been run with various values, and it succeeds except for one test case: windowsAbsolutePath that might encounter a go validator.v2 package internal trouble.

Tests are in modules/openapi-generator/src/test/resources/3_0:
ls modules/openapi-generator/src/test/resources/3_0/issue_20079_*

issue_20079_go_regex_wrongly_translated.yaml

# For testing purpose
issue_20079_api_default_test.go                               # In the sample, replace test/api_default_test.go by this one
issue_20079_matching01.json                                   # Copy these candidates json files along
issue_20079_matching02.json
issue_20079_matching03.json
issue_20079_matching04.json
issue_20079_non_matching01.json
issue_20079_non_matching02.json
issue_20079_non_matching03.json
issue_20079_non_matching04.json

The following command should then show the success:

go mod tidy && go vet ./... && go test ./... -v

Remaining problem

This fix mostly fixes the handling of regular expressions with Go.
But there's still two problems remaining, that will require other issues to be handled 👍

1. For javaComments test case, when it should use the ^/\*.*\*/|//[^\\n]*$ pattern, the org.yaml.snakeyaml.scanner parser that scans the spec file, wrongly tells that \* is an invalid escape code.
   But attempting to enter ^/\\*.*\\*/|//[^\\n]*$ keeps the \\* and generates ^/\\*.*\\*/|//[^\n]*$ instead of the wished ^/\*.*\*/|//[^\n]*$

2. For windowsAbsolutePath test case, Go validator.package v2 doesn't look handling this regexp well, and tell it having a bad parameter.

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[wing328]

thanks for the PR

can you please rebase/merge the latest master, which should have the gradle tests fixed?

[wing328]

cc @antihax (2017/11) @grokify (2018/07) @kemokemo (2018/09) @jirikuncar (2021/01) @ph4r5h4d (2021/04) @lwj5 (2023/04)

[mlebihan]

It should be done, now.

[wing328]

thanks for the PR and adding the tests.

can you please PM me to discuss the integration tests when you've time?

Slack: https://join.slack.com/t/openapi-generator/shared_invite/zt-2wmkn4s8g-n19PJ99Y6Vei74WMUIehQA

[srgoni]

Will this PR also fix #22101 ?
It seems to be quite a similar issue.

[wing328]

@srgoni do you mind pulling this change locally to test with your use cases?

[markshleifer-coralogix]

@wing328 I faced the same issue.
I pulled this PR branch locally and tested the same case. The generated Go tag is now correct.
Do you have an estimated ETA for merging/releasing this fix?

[wing328]

@markshleifer-coralogix thanks for testing the fix.

will try to get it merged in the upcoming stable release.

[mlebihan]

@wing328 I've tested this PR against the tests that are here: samples/client/others/go/issue_20079_go_regex_wrongly_translated/test.

With various matching cases:

{
  "code": "52,",
  "creditCard": "3124 5675 4400 4567",
  "date": "31/4/1999",
  "windowsAbsolutePath": "\\\\directory\\\\directory2",

  "email1": "abc@dummy",
  "email2": "abc.123.*&ca",
  "htmlHexadecimalColorCode1": "123G45",
  "htmlHexadecimalColorCode2": "SS AB CD",
  "ipAddress": "0.0.0",

  "javaComments": "a=1",
  "money": "$1",
  "positiveNegativeDecimalValue": "++41",
  "password1": "abc",
  "password2": "*&^g",

  "phoneNumber": "888 6898",
  "sentence1": "i am fine",
  "sentence2": "i am fine",
  "socialSecurityNumber": "123 45 6789",
  "url": "http://sample.com"
}

and not matching ones:

{
  "code": "52,",
  "creditCard": "4123-6453-2222-1746",
  "date": "1999/04/19",
  "windowsAbsolutePath": "/directory2",

  "email1": "ab*cd@efg.hijkl",
  "email2": "^%abcdefg123",
  "htmlHexadecimalColorCode1": "12-44-CC",
  "htmlHexadecimalColorCode2": "1223AB",
  "ipAddress": "256.89.457.02",

  "javaComments": "a=1",
  "money": "$-75.17",
  "positiveNegativeDecimalValue": "-+97.14",
  "password1": "*abcdefghijkl",
  "password2": "1bcd",

  "phoneNumber": "519 883-6898",
  "sentence1": "i am fine",
  "sentence2": "i am fine",
  "socialSecurityNumber": "1234-56-7891",
  "url": "http://www.sample.comm"
}

This PR improves the situation, but there's still two cases failing.
windowsAbsolutePath if I remember well, is one of them.

I cannot succeed in correcting completely this issue, however, because there's a flaw in one of the underlying packages Go uses to validate or use regex.

So, I'm happy and glad if this PR can solve many regex that causes troubles. But it won't fix them all.