Change FlushAsync to SendEndOfMessageAsync

[Shane32]

This prevents the possibility that System.Text.Json calls Flush and send an end-of-message mark when it should not.

Summary by CodeRabbit

• Bug Fixes

  • Improved WebSocket message transmission with corrected end-of-message signaling for enhanced protocol compliance and connection reliability. Stream flush operations and end-of-message signaling are now properly separated.

• Tests

  • Updated WebSocket tests to validate the new end-of-message handling behavior.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes refactor WebSocket stream message handling by separating the FlushAsync method—now a no-op—from a new explicit SendEndOfMessageAsync method that signals message completion. Call sites are updated to use the new method for proper end-of-message semantics.

Changes

Cohort / File(s)	Summary
WebSocket Stream Refactoring src/GraphQL.AspNetCore3/WebSockets/WebSocketWriterStream.cs	FlushAsync() replaced with no-op returning Task.CompletedTask; new public SendEndOfMessageAsync(CancellationToken) method added to send end-of-message on underlying WebSocket; new public Flush() no-op method added
WebSocket Connection Update src/GraphQL.AspNetCore3/WebSockets/WebSocketConnection.cs	OnSendMessageAsync now calls SendEndOfMessageAsync() instead of FlushAsync() after writing message to stream
Test Updates src/Tests/WebSockets/WebSocketWriterStreamTests.cs	Previous FlushAsync() test renamed to SendEndOfMessageAsync() with updated assertions; new FlushAsync() test added to verify no-op behavior

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

• Areas requiring attention:
  • Verify that SendEndOfMessageAsync correctly delegates to the underlying WebSocket's end-of-message semantics
  • Confirm that changing FlushAsync to a no-op doesn't break any external consumers relying on the old flushing behavior
  • Validate test coverage for both methods properly reflects their distinct behaviors

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 10.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The pull request title accurately describes the main API change: renaming FlushAsync to SendEndOfMessageAsync across the WebSocket-related files, which is reflected in the actual code changes.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fixflush

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between dd56890 and ed836c4.

📒 Files selected for processing (3)

• src/GraphQL.AspNetCore3/WebSockets/WebSocketConnection.cs (1 hunks)
• src/GraphQL.AspNetCore3/WebSockets/WebSocketWriterStream.cs (1 hunks)
• src/Tests/WebSockets/WebSocketWriterStreamTests.cs (1 hunks)

🧰 Additional context used

🧬 Code graph analysis (2)

src/GraphQL.AspNetCore3/WebSockets/WebSocketWriterStream.cs (1)

src/GraphQL.AspNetCore3/WebSockets/WebSocketConnection.cs (8)

• Task (82-162)
• Task (165-166)
• Task (169-174)
• Task (177-183)
• Task (193-204)
• Task (212-213)
• Task (221-225)
• Task (233-234)

src/Tests/WebSockets/WebSocketWriterStreamTests.cs (2)

src/GraphQL.AspNetCore3/WebSockets/WebSocketConnection.cs (8)

• Task (82-162)
• Task (165-166)
• Task (169-174)
• Task (177-183)
• Task (193-204)
• Task (212-213)
• Task (221-225)
• Task (233-234)

src/GraphQL.AspNetCore3/WebSockets/WebSocketWriterStream.cs (3)

• Task (12-13)
• Task (22-22)
• Task (26-27)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)

• GitHub Check: test (windows-latest)
• GitHub Check: test (ubuntu-latest)

🔇 Additional comments (5)

src/GraphQL.AspNetCore3/WebSockets/WebSocketWriterStream.cs (2)

22-24: Correct Stream semantics for Flush methods.

Making both FlushAsync and Flush no-ops aligns with proper Stream semantics, where flushing ensures buffered data is written but doesn't control protocol-level message boundaries. This prevents serializers that call FlushAsync from prematurely finalizing WebSocket messages.

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26-27: Clean implementation of explicit end-of-message signaling.

The method correctly sends an empty buffer with endOfMessage = true to finalize the WebSocket message. Using Array.Empty<byte>() is efficient as it returns a cached singleton.

src/Tests/WebSockets/WebSocketWriterStreamTests.cs (2)

54-61: Thorough test coverage for SendEndOfMessageAsync.

The test correctly verifies that SendEndOfMessageAsync sends an empty buffer with endOfMessage = true to the underlying WebSocket, and that no other calls are made. The mock setup properly validates the expected behavior.

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63-69: Proper test coverage for no-op FlushAsync.

The test correctly verifies that FlushAsync no longer makes any calls to the underlying WebSocket. The absence of mock setup and the VerifyNoOtherCalls assertion properly validate the no-op behavior.

src/GraphQL.AspNetCore3/WebSockets/WebSocketConnection.cs (1)

221-225: Verification confirms: change is comprehensive and handles all message serialization paths.

The search results show only one production code path uses _serializer.WriteAsync with _stream in WebSocketConnection.cs line 223 (the changed method). The other _serializer.WriteAsync call in GraphQLHttpMiddleware writes to an HTTP response stream, which has different semantics and doesn't require end-of-message signaling. No other code paths bypass the SendEndOfMessageAsync call, confirming this change properly addresses all WebSocket message boundaries.

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[github-actions]

Coverage Report

Totals
Statements:	93.77% ( 2061 / 2198 )
Methods:	80.93% ( 314 / 388 )

[coveralls]

Pull Request Test Coverage Report for Build 19690454137

Details

• 4 of 4 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.06%) to 91.732%

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Totals
Change from base Build 15600896893:	0.06%
Covered Lines:	2061
Relevant Lines:	2198

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💛 - Coveralls