[ashishdhingra]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

The aws-eventstream encoder now validates header fields against the event stream protocol limits before serializing a message, and raises an error instead of writing a value that doesn't fit its field.

aws-eventstream

• Header names longer than 255 encoded bytes raise EventHeaderNameLengthExceedError.
• string and bytes header values longer than 32,767 encoded bytes raise EventHeaderValueLengthExceedError.
• Fixed-width header values that don't fit their type raise EventHeaderValueWidthError: uuid values must be exactly 16 bytes, and byte, short, integer, long, and timestamp values must fit their signed width.
• Lengths are measured in encoded bytes, not characters.
• Validation runs before anything is written, so a rejected message writes nothing to the output IO.

aws-sdk-core

• Requires aws-eventstream >= 1.4.1.
• MINIMUM_CORE_VERSION for newly built service gems is bumped to 3.259.0.

Changelog entries are under Unreleased Changes for both gems.

Testing

• aws-eventstream specs: 46 examples, 0 failures. New cases cover 255/256-byte names; 32,767/32,768/65,536-byte string and bytes values; multibyte values whose character count is within the limit but whose byte length exceeds it; valid and invalid widths for each fixed-width type; and failure atomicity.

---

Generated by AI tools (Claude Code), and reviewed by Ashish Dhingra.

[ashishdhingra]

Dry-run triggered:

{
  "buildId": "5714428c-1b1e-4328-bcf8-8d4374e5305b",
  "buildType": "DRY_RUN",
  "stage": "PROD",
  "overrides": {
    "sources": [
      {
        "sourceId": "aws-sdk-ruby",
        "sourceReference": "eventstream-header-validation"
      }
    ]
  }
}

[jterapin]

Please recheck the bump after release today.

[sankettangade]

Non-blocking: message_with_header is defined the same way in both new describe blocks here and on L182. Could it move up one level so it's shared?

[ashishdhingra]

New dry-run started after changing MINIMUM_CORE_VERSION to 3.260.0:

{
  "buildId": "2785026d-e3d3-4d6a-8fa1-25d04d1a7dda",
  "buildType": "DRY_RUN",
  "stage": "PROD",
  "overrides": {
    "sources": [
      {
        "sourceId": "aws-sdk-ruby",
        "sourceReference": "eventstream-header-validation"
      }
    ]
  }
}