feat: Add tags in output.tf #355

[paikend]

Description

Added s3_bucket_tags output to expose user-defined tags applied to S3 buckets. This output provides access to the tags that users explicitly set via the tags variable, enabling tag validation and testing in downstream configurations.

Motivation and Context

The module was missing an output for S3 bucket tags, which is commonly needed for:

• Automated tag validation in Terraform tests
• Tag consistency checks across infrastructure
• Integration with other modules that need to reference bucket tags
• Compliance and governance validation

This addresses the need for accessing user-defined bucket tags without exposing computed-only values like tags_all.

Breaking Changes

This is a non-breaking change. It only adds a new output without modifying any existing functionality or outputs.

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects
• I have executed pre-commit run -a on my pull request

Testing Details

• Validated the output returns the expected tags in the complete example
• Confirmed the output works correctly when no tags are provided (returns empty object)
• Tested integration with conditional bucket creation scenarios using the try() function
• Added test case to validate tag accessibility:

run "validate_tags_output" {
  command = plan
  
  variables {
    tags = {
      Environment = "test"
      Project     = "terraform-aws-s3-bucket"
    }
  }
  
  assert {
    condition = module.s3_bucket.s3_bucket_tags.Environment == "test"
    error_message = "S3 bucket tags output should include Environment tag"
  }
  
  assert {
    condition = length(keys(module.s3_bucket.s3_bucket_tags)) == 2
    error_message = "S3 bucket tags output should contain exactly 2 tags"
  }
}

The output safely handles edge cases using try(aws_s3_bucket.this[0].tags, {}) to return an empty object when the bucket resource doesn't exist.

[antonbabenko]

Looks pretty good, please fix CI before the merge.

[paikend]

Sorry, I Fixed it

[antonbabenko]

This PR is included in version 5.7.0 🎉