Fix: Nil pointer dereference in Arabic translations

[BlackSud0]

Fixes or Enhances

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• Tests exist or have been written that cover this particular change.

Description

This PR fixes [Bug #1385]: Nil pointer dereference in Arabic translations and adds comprehensive Arabic (ar) translations for the go-playground/validator package. The implementation provides Arabic error messages for all common validation tags, making the validator more valuable to Arabic-speaking developers.

Features

• Fixes nil pointer dereference bug in Arabic translations
• Complete Arabic translations for all standard validation tags
• Comprehensive test suite to verify translation accuracy
• Follows the same pattern as existing language translations
• Properly handles Arabic text direction and grammar

Implementation Details

• The implementation follows the established pattern in the validator package:
• Registers translations for each validation tag
• Provides appropriate Arabic phrasing for validation errors
• Handles parameter substitution in error messages
• Includes tests for all validation scenarios

Testing

• A comprehensive test suite is included that verifies:
• Basic validations (required, email, etc.)
• Length validations (min, max, len)
• Comparison validations (lt, lte, gt, gte, eq, ne)
• Field comparison validations (eqfield, nefield, gtefield)
• Content validations (alpha, alphanum, contains, etc.)
• Special validations (oneof, datetime)
• All tests pass and confirm that the translations are correctly applied.

Usage Example

validate := validator.New()
arabic := ar.New()
uni := ut.New(arabic, arabic)
trans, _ := uni.GetTranslator("ar")

// Register Arabic translations
ar.RegisterDefaultTranslations(validate, trans)

// Now validation errors will be in Arabic
err := validate.Struct(myStruct)
if err != nil {
    errs := err.(validator.ValidationErrors)
    for _, e := range errs {
        // This will be in Arabic
        fmt.Println(e.Translate(trans))
    }
}

@nodivbyzero
@go-playground/validator-maintainers

[coveralls]

coverage: 74.712% (-0.4%) from 75.084%
when pulling f37f31f on BlackSud0:master
into 45dd6e3 on go-playground:master.

[nodivbyzero]

Overall, it looks good to me.
Would it be possible to add more tests?
The current coverage is quite low at 39.2%.

$ go test ./translations/ar -coverprofile ar-coverage.out
ok      github.com/go-playground/validator/v10/translations/ar  0.249s  coverage: 39.2% of statements

[BlackSud0]

My latest commit enhances the Arabic (ar) translations by adding support for several validation tags that were previously missing and improving test coverage. The current test coverage was approximately 56.9%.

Changes

Added translations for the following validation tags:

• fqdn - Fully Qualified Domain Name validation
• cron - Cron expression validation
• md5 - MD5 hash validation
• sha256 - SHA256 hash validation
• semver - Semantic versioning validation

Added special handling for duration validations:

• Custom translation registrations for the min and max tags when applied to time.Duration fields
• Created Arabic translations for duration-related error messages

Expanded test coverage:

• Added test cases for all new validation tags
• Added test expectations for duration, boolean, cve, and other validators