I tried this a few weeks ago, but then thought I may have jumped the gun so reverted back to 2.7.1, but tried again today.
meteor.js?hash=7dd187e6c4c7dc8731ddaf9d1d993d3c3ba5a732:1124 Exception in defer callback: TypeError: Cannot convert undefined or null to object at Function.entries (<anonymous>) at waitForAllAttributesAndContinue (materializer.js:100:37) at Blaze.View.updateAttributes (materializer.js:159:7) at view.js:206:20 at Template._withTemplateInstanceFunc (template.js:492:14) at view.js:204:29 at Blaze._withCurrentView (view.js:554:12) at viewAutorun (view.js:203:18) at tracker.js:331:47 at Tracker.withComputation (tracker.js:640:12)
I’ve hit this too when upgrading to this version of Blaze. Sounds a bit silly, but I simply removed all the package caches in the local meteor folder and the user home folder, and it worked. Here are some instructions for Linux. Inside the .meteor/local folder execute:
You can go ahead and remove the versions file too. Then in your home folder, for good measure, in the .meteor/packages, remove the blaze and blaze-html-templates packages.
This is as hacky as it’s quick. But all these will be rebuilt at first meteor run ..., so not much to worry about. Hopefully there will be a fix for this, so would be good if you can open an issue with reproducible steps for it.
Thank you for those steps. There is good news and bad news! The bad news is it didn’t fix the error. Or more accurately the error changed. The good news is that what I am now seeing is a confirmed bug in Blaze 2.8 with an issue already raised - https://github.com/meteor/blaze/issues/456