Skip empty lines

[kaleev]

Motivation and Context

This pull request fixes an issue with the ReadBuffer functionality by ensuring that empty lines are properly skipped during input processing. A new test case has been added to validate this behavior.

How Has This Been Tested?

The ReadBuffer threw exception on empty message which leaded to connection closing.

Breaking Changes

no

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[kaleev]

@e5l, could you please take a look?

[Copilot]

Pull Request Overview

This pull request fixes an issue with the ReadBuffer functionality by properly skipping empty lines during input processing. The changes include:

• Updating ReadBuffer to return null for empty lines instead of an empty string.
• Adding a new test case to ensure the empty line behavior is correctly handled.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/jvmTest/kotlin/shared/ReadBufferTest.kt	Added a test to validate that an empty line returns null.
src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/ReadBuffer.kt	Modified the empty line handling to return null after skipping the newline.

Comments suppressed due to low confidence (1)

src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/shared/ReadBuffer.kt:27

• Changing from returning an empty string to null on an empty line fixes the issue reported with the ReadBuffer, but please ensure that this behavior is consistent with the overall contract of readMessage() and doesn’t cause side effects elsewhere.

return null

[e5l]

Hey @kaleev, thanks for the PR. LGTM