Literals with escaped interpolations work

[mitchellh]

Fixes #2909

If you had a literal with an escaped interpolation such as foo-$${bar} it was not properly turning into foo-${bar}. This fixes that.

The fix is simple: we had an optimization where if after we parsed the string for interpolations we found only a literal we assumed there was nothing and skipped it. We now check to make sure the result is also the same string and if not, we still evaluate the string.

[mitchellh]

Real failing tests :( I'll look

[mitchellh]

Fixed tests

[apparentlymart]

LGTM!

Thanks for fixing this... it was messing with me just last week when I was trying to use Rundeck interpolations, which happen to use the same syntax as Terraform, and it was really bugging me why the escaping sometimes worked and sometimes didn't. Nice to see that there's a reasonable explanation for that. 😄

[phinze]

LGTM

[rkul]

Interpolation escaping also doesn't work for templates. If template contains $${var}, it renders into $${var}.
Simple workaround is to use replace func when rendering:
${replace(template_file.config.rendered,"$$","$")}

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.