Check if MySQL supports CLIENT_CONNECT_ATTRS before sending client attributes.

[raffertyyu]

Description

Check if MySQL supports CLIENT_CONNECT_ATTRS before sending client attributes.

Checklist

• Code compiles correctly
• Created tests which fail without the change (if possible)
• All tests passing
• Extended the README / documentation, if necessary
• Added myself / the copyright holder to the AUTHORS file

Summary by CodeRabbit

• New Features

  • Improved handling of MySQL connection packets, enhancing the handshake process.
  • Conditional inclusion of connection attributes based on server capabilities.

• Bug Fixes

  • Enhanced error handling for connection errors and malformed packets, improving robustness in connection management.

These changes ensure better compliance with MySQL protocol specifications and enhance overall performance.

[coderabbitai]

Walkthrough

The changes in this pull request focus on enhancing the handling of MySQL connection packets within the packets.go file. Key modifications include refined parsing of handshake packets, improved logic for capability flags, and conditional adjustments for connection attributes in the handshake response. Error handling has also been strengthened to ensure proper closure of connections and logging of errors during packet processing, all while maintaining compliance with MySQL protocol specifications.

Changes

File	Change Summary
packets.go	- Refined parsing in readHandshakePacket, updated capability flags handling.
	- Modified logic for determining authentication plugin data length.
	- Adjusted client flags in writeHandshakeResponsePacket based on server capabilities.
	- Streamlined handling of connection attributes, ensuring conditional transmission.
	- Enhanced error handling for connection errors and malformed packets.

Poem

🐇 In packets swift, we dance and play,
With MySQL's whispers, we find our way.
Flags set just right, no data to waste,
Errors now caught, no time to haste.
A handshake refined, like a rabbit's delight,
In the world of connections, we hop with might! 🌟

---

📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between a343408 and 782166f.

📒 Files selected for processing (1)

• packets.go (4 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• packets.go

---

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[coderabbitai]

Actionable comments posted: 0

🧹 Outside diff range and nitpick comments (1)

packets.go (1)

269-270: Variable naming: improve clarity of serverSupportClientConnectAttrs.

Consider renaming serverSupportClientConnectAttrs to serverSupportsConnectAttrs for grammatical correctness and enhanced readability.

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between f62f523 and a343408.

📒 Files selected for processing (1)

• packets.go (4 hunks)

🔇 Additional comments (4)

packets.go (4)

213-218: Parsing handshake packet fields correctly.

The updated code properly advances the position pos to account for the character set, status flags, upper capability flags, length of auth-plugin-data, and the reserved bytes. This ensures accurate parsing of the handshake packet according to the MySQL protocol specification.

---

266-269: Proper handling of client flags based on server capabilities.

Including mc.flags&clientConnectAttrs and mc.flags&clientLongFlag in clientFlags ensures that the client only advertises capabilities supported by both the client and the server. This conditional capability negotiation is appropriate and aligns with the MySQL protocol.

---

302-309: Conditionally encoding connection attributes based on server support.

The code correctly conditionally encodes the length and content of the connection attributes only if the server supports CLIENT_CONNECT_ATTRS. This prevents sending unnecessary data to servers that do not support connection attributes, ensuring proper protocol compliance.

---

392-395: Conditionally sending connection attributes in handshake response.

By wrapping the sending of connection attributes within the if serverSupportClientConnectAttrs condition, the client avoids transmitting connection attributes to servers that do not support them. This safeguards against potential compatibility issues and adheres to the MySQL protocol specifications.

[coveralls]

coverage: 82.418% (+0.03%) from 82.39%
when pulling 782166f on raffertyyu:master
into f62f523 on go-sql-driver:master.

[methane]

would you add your name to AUTHORS?

[raffertyyu]

Maybe next time. It's ok for me.