From c5805af9358b59181f9dce686ee832164bc86748 Mon Sep 17 00:00:00 2001
From: Trevor Buckner <calculuschild@gmail.com>
Date: Thu, 10 Jul 2025 11:12:42 -0400
Subject: [PATCH] On patch failure, compare client and server text bytewise

---
 server/homebrew.api.js |  3 ++-
 shared/helpers.js      | 38 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/server/homebrew.api.js b/server/homebrew.api.js
index e34195ffa..2a7851c7f 100644
--- a/server/homebrew.api.js
+++ b/server/homebrew.api.js
@@ -11,7 +11,7 @@ import { nanoid }                    from 'nanoid';
 import {makePatches, applyPatches, stringifyPatches, parsePatch} from '@sanity/diff-match-patch';
 import { md5 }                       from 'hash-wasm';
 import { splitTextStyleAndMetadata, 
-		 brewSnippetsToJSON }        from '../shared/helpers.js';
+		 brewSnippetsToJSON, debugTextMismatch }        from '../shared/helpers.js';
 import checkClientVersion            from './middleware/check-client-version.js';
 
 
@@ -364,6 +364,7 @@ const api = {
 			const patchedResult = applyPatches(patches, brewFromServer.text)[0];
 			// brew.text = applyPatches(patches, brewFromServer.text)[0];
 		} catch (err) {
+			debugTextMismatch(brewFromClient.text, brewFromServer.text, `edit/${brewFromClient.editId}`);
 			console.error('Failed to apply patches:', {
 				patches : brewFromClient.patches,
 				brewId  : brew.editId || 'unknown',
diff --git a/shared/helpers.js b/shared/helpers.js
index 0ca681dfb..e09b0bdc4 100644
--- a/shared/helpers.js
+++ b/shared/helpers.js
@@ -139,9 +139,45 @@ const fetchThemeBundle = async (obj, renderer, theme)=>{
 	}));
 };
 
+const debugTextMismatch = (clientTextRaw, serverTextRaw, label) => {
+	const clientText = clientTextRaw?.normalize('NFC') || '';
+	const serverText = serverTextRaw?.normalize('NFC') || '';
+
+	const clientBuffer = Buffer.from(clientText, 'utf8');
+	const serverBuffer = Buffer.from(serverText, 'utf8');
+
+	if (clientBuffer.equals(serverBuffer)) {
+		console.log(`✅ ${label} text matches byte-for-byte.`);
+		return;
+	}
+
+	console.warn(`❗${label} text mismatch detected.`);
+	console.log(`Client length: ${clientBuffer.length}`);
+	console.log(`Server length: ${serverBuffer.length}`);
+
+	// Byte-level diff
+	for (let i = 0; i < Math.min(clientBuffer.length, serverBuffer.length); i++) {
+		if (clientBuffer[i] !== serverBuffer[i]) {
+			console.log(`Byte mismatch at offset ${i}: client=0x${clientBuffer[i].toString(16)} server=0x${serverBuffer[i].toString(16)}`);
+			break;
+		}
+	}
+
+	// Char-level diff
+	for (let i = 0; i < Math.min(clientText.length, serverText.length); i++) {
+		if (clientText[i] !== serverText[i]) {
+			console.log(`Char mismatch at index ${i}:`);
+			console.log(`  Client: '${clientText[i]}' (U+${clientText.charCodeAt(i).toString(16).toUpperCase()})`);
+			console.log(`  Server: '${serverText[i]}' (U+${serverText.charCodeAt(i).toString(16).toUpperCase()})`);
+			break;
+		}
+	}
+}
+
 export {
 	splitTextStyleAndMetadata,
 	printCurrentBrew,
 	fetchThemeBundle,
-	brewSnippetsToJSON
+	brewSnippetsToJSON,
+	debugTextMismatch
 };