Expression: object->InternalFieldCount() > 0

[svantonov]

Steps to Reproduce

var Canvas = require('canvas');
var canvas = new Canvas(200, 200);
...

Error

Assertion failed!

Program: ...\node_modules\canvas\build\Release\canvas.node
File: ...\node_modules\nan\nan_object_wrap.h

Expression: object->InternalFieldCount() > 0
....

Environment

• Version of node-canvas (e.g. v1.6.2):
• Environment (e.g. node v6.9.1 (x64) on Windows 10):

[zbjornson]

This is fixed by #808 :-)

[svantonov]

I used installing instructions for Windows and nothing changed in node-canvas code.
Node installer download from official website.
Is fix already applied to v1.6.2 release?

[zbjornson]

Ah, sorry for not being clear. #808 is not merged into master yet.

The other people who have reported this problem only got the assertion failure while a debugger was attached. If you need an immediate fix, you could use the branch for #808 (npm install github:zbjornson/node-canvas#prototype-fix), or try not using a debugger if you're using one...

[svantonov]

Thank you. But this fix just halt application (in debug mode) without any message.
I used debug mode with Visual Studio Code.
Application works without debug.

[zbjornson]

OK, using my branch from #808, I can reproduce the failure with Visual Studio Code in both launch and attach modes if I put a breakpoint after your 1st line (procdump says 0xc0000005, access violation), but I cannot reproduce it with Visual Studio or with the node.js built-in debugger.

I don't know how VSCode's debugger works with node to try to troubleshoot this further, unfortunately. I can't tell if this is from node-canvas or vscode, but it's odd that it only happens wtih vscode's debugger.

[ip]

I'm experiencing the same problem:

It crashes on the line with new Canvas(...) and this is not specific to VS Code or which Node.js debugging protocol is used. I tried it also with node-inspector.

[zbjornson]

Oops, I had a typo in PR #808 -- it should have said "Fixes #855" (this issue). This is fixed in 2.0-alpha.

[webworker01]

Hello I am receiving this error on canvas@2.0.0-alpha.5

[zbjornson]

@webworker01 is there a particular line of your code that causes it to happen?

[feuerste]

@zbjornson would it be a lot of effort to backport PR #808 into the 1.x series?