Merge pull request #16 from sharelatex/ja-consistency-tweaks

Ja consistency tweaks

services/track-changes/app/coffee/DiffGenerator.coffee

@@ -18,7 +18,7 @@ module.exports = DiffGenerator =
 				if e instanceof ConsistencyError and i = update.op.length - 1
 					# catch known case where the last op in an array has been
 					# merged into a later op
-					logger.error {update, op: JSON.stringify(op)}, "marking op as broken"
+					logger.error {err: e, update, op: JSON.stringify(op)}, "marking op as broken"
 					op.broken = true
 				else
 					throw e # rethrow the execption

services/track-changes/app/coffee/DiffManager.coffee

@@ -5,11 +5,12 @@ logger = require "logger-sharelatex"
 
 module.exports = DiffManager =
 	getLatestDocAndUpdates: (project_id, doc_id, fromVersion, toVersion, callback = (error, content, version, updates) ->) ->
-		# retrieve the document before retreiving the updates,
-		# because updates are written to mongo after the document
-		DocumentUpdaterManager.getDocument project_id, doc_id, (error, content, version) ->
+		# Whichever order these are in, there is potential for updates to come in between
+		# them so that they do not return the same 'latest' versions.
+		# TODO: If these don't return consistent content, try again.
+		UpdatesManager.getDocUpdatesWithUserInfo project_id, doc_id, from: fromVersion, to: toVersion, (error, updates) ->
 			return callback(error) if error?
-			UpdatesManager.getDocUpdatesWithUserInfo project_id, doc_id, from: fromVersion, to: toVersion, (error, updates) ->
+			DocumentUpdaterManager.getDocument project_id, doc_id, (error, content, version) ->
 				return callback(error) if error?
 				callback(null, content, version, updates)
 	
@@ -49,6 +50,8 @@ module.exports = DiffManager =
 			lastUpdate = updates[0]
 			if lastUpdate? and lastUpdate.v != version - 1
 				return callback new Error("latest update version, #{lastUpdate.v}, does not match doc version, #{version}")
+			
+			logger.log {docVersion: version, lastUpdateVersion: lastUpdate?.v, updateCount: updates.length}, "rewinding updates"
 
 			tryUpdates = updates.slice().reverse()
 

services/track-changes/app/coffee/DocumentUpdaterManager.coffee

@@ -14,6 +14,7 @@ module.exports = DocumentUpdaterManager =
 					body = JSON.parse(body)
 				catch error
 					return callback(error)
+				logger.log {project_id, doc_id, version: body.version}, "got doc from document updater"
 				callback null, body.lines.join("\n"), body.version
 			else
 				error = new Error("doc updater returned a non-success status code: #{res.statusCode}")