[BUG] recursive failure in TestCaseWidget transclusion tests beginning with {{{}}

[96eron]

Describe the bug

Typing "{{{}}" or "{{{}}}" in the TestCaseWidget (intending to fill it with content in the next step) results in unexpected recursive error handling and frozen output in the right preview box

Expected behavior

• not such a odd output, error handling
• no freezing of the preview-box

To Reproduce

1. goto tiddlywiki.com to tiddler TestCaseWidget: https://tiddlywiki.com/#TestCaseWidget
2. goto bluebox "Simple transclusion" left sided textfield tab: 'output'
3. clear content
4. input '{{{}}}' or '{{{}}'
5. you'll see unexpected recursive error handling and frozen output in the right preview box

Screenshots

TiddlyWiki Configuration

• Version 5.3.5
• Saving mechanism: to reproduce it, no saving necessary
• Plugins installed: plugins didn't affect

Desktop (please complete the following information):

• OS: several
• Browser safari, firefox
• Version several

Smartphone (please complete the following information):

• Device: several
• OS: several (iPad, iphone)

Additional context

No response

[pmario]

I can confirm this problem. It also happens with the preview pane in tiddler edit mode. There are 2 experiments going on see:

• 8155

• 8147

@Jermolene we should give them a second review