[Bug]: Node export to dataURL is wrong

[xorb]

CheckList

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• [X] I am filing a BUG report.
• [X] I have managed to reproduce the bug after upgrading to the latest version
• [X] I have created an accurate and minimal reproduction

Version

6.0.0-beta16

In What environments are you experiencing the problem?

Node.js

Node Version (if applicable)

None

Link To Reproduction

https://codesandbox.io/p/devbox/fabric-node-dflwyw?file=%2Fsrc%2Findex.ts%3A14%2C1

Steps To Reproduce

1. Open demo link
2. Wait for images to be rendered
3. Compare image outputs png vs svg

Expected Behavior

Actual Behavior

Error Message & Stack Trace

1. This happens in fabric 6.x and 5.x (node).
2. In the browser it seems to be working as expected

[ShaMan123]

This is a bug that can be fixed by #8298 The problem is the absence of context isolation. Fabric confuses context isolation and object caching. Initially object caching was planned for performance I think but then the need for context isolation came and caching was reused for that purpose. This flaw in design has many bugs to blame. Enough of design context. In node object caching is turned off by default, meaning there is no context isolation by default. Since your group has an opacity value and there is no context isolation the opacity value leaks to each object instead of being applied to the group context. The workaround is simple, set objectCaching: true as I did here but that might open the door for new bugs that are related to this issue (shadow rendering for example)

@ebigtm