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Implement signed byte conversion for checksum to fix #3765 #1442

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Implement signed byte conversion for checksum to fix #3765 #1442

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7 changes: 6 additions & 1 deletion src/client/chat.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,11 @@ const concat = require('../transforms/binaryStream').concat
const { processNbtMessage } = require('prismarine-chat')
const messageExpireTime = 420000 // 7 minutes (ms)

const toSignedByte = (value) => {
const byte = value & 0xff
return byte > 127 ? byte - 256 : byte
}
Comment on lines +7 to +10
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Copilot AI Dec 16, 2025

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Consider moving the toSignedByte function to src/datatypes/checksums.js and exporting it alongside computeChatChecksum. This would improve code organization by grouping related checksum functionality together and make the function reusable if needed elsewhere. The function is specifically designed to handle the signed byte requirement for checksums in the Minecraft protocol.

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@brentspine brentspine Dec 16, 2025

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@copilot coauthor pr #1442 based on this this feedback


function isFormatted (message) {
// This should match the ChatComponent.isDecorated function from Vanilla
try {
Expand Down Expand Up @@ -377,7 +382,7 @@ module.exports = function (client, options) {
salt: options.salt,
argumentSignatures: canSign ? signaturesForCommand(command, options.timestamp, options.salt, options.preview, acknowledgements) : [],
messageCount: client._lastSeenMessages.pending,
checksum: computeChatChecksum(client._lastSeenMessages), // 1.21.5+
checksum: toSignedByte(computeChatChecksum(client._lastSeenMessages)), // 1.21.5+
acknowledged
}
client.write((mcData.supportFeature('seperateSignedChatCommandPacket') && canSign) ? 'chat_command_signed' : 'chat_command', chatPacket)
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