HTML coverage report is not outputting correctly

[agubler]

Expected behavior

The HTML report to be output correctly and no handlebar wanrings printed to the terminal

Current behavior

The HTML report is empty and handlebars warnings are printed to the terminal

Handlebars: Access has been denied to resolve the property "statements" because it is not an "own property" of its parent.
You can add a runtime option to disable the check or this warning:
See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details
Handlebars: Access has been denied to resolve the property "branches" because it is not an "own property" of its parent.
You can add a runtime option to disable the check or this warning:
See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details
Handlebars: Access has been denied to resolve the property "functions" because it is not an "own property" of its parent.
You can add a runtime option to disable the check or this warning:
See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details
Handlebars: Access has been denied to resolve the property "lines" because it is not an "own property" of its parent.
You can add a runtime option to disable the check or this warning:
See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details

Possible solution

Possibly update dependency that uses handlebars?

Steps to reproduce (for bugs)

1. Clone github.com/dojo/framework
2. npm install
3. npm test
4. Open the coverage report coverage/html-report/index.html

Environment

Intern version: 4.3.5
Node version: 12.13.1
NPM version: 6.12.1
Browser version: N/A

Additional information

N/A

[jason0x43]

The problem doesn't occur with a dev install of framework (i.e., what you get by running npm install in framework), which uses handlebars 4.5.3. However, it does occur if you're using handlebars 4.7.2, which is what users of framework would probably end up with.

[jason0x43]

This is due to an intentional change to handlebars in 4.6 (handlebars-lang/handlebars.js#1642). It's not an issue for Intern 5 since it's using istanbul-reports@2, which dropped handlebars. However, we'll either need to pin handlebars for Intern 4.x, or see if Istanbul-reports@2 will work without too much of an overhaul.

[jason0x43]

This should also be updated in Intern 4.8 and 4.x. We can backport it as necessary.

[jason0x43]

4.8 and 4.x have been updated.