Tabs in strings renders non-obvious error message

[anderseknert]

Placing an actual tab character (and not \t) in a regular string results in a non-obvious and hard to debug error message.

foo := "	foo"

1 error occurred: policy.rego:3: rego_parse_error: unexpected assign token: expected rule value term (e.g., foo := <VALUE> { ... })
	foo := "	foo"
	    ^

Whether this should be allowed or not, I don't know. But it's obviously not the assign token that's an issue here, so if this should be an error it should at least be reported accurately.

What does work:

foo := "\tfoo"
foo := `	foo`

[srenatus]

Another variant of this, I suppose: #1129 -- No wait, it's not. Ignore me 😅 Well, maybe a bit.

[anderseknert]

🙂 Yeah, somewhat related!

Further research says that the tab character must be escaped as else it would not be a valid JSON value. So it's correct to flag this as an error. The error message should say something like "illegal tab character in string — use escape character \t instead".

[stale]

This issue has been automatically marked as inactive because it has not had any activity in the last 30 days. Although currently inactive, the issue could still be considered and actively worked on in the future. More details about the use-case this issue attempts to address, the value provided by completing it or possible solutions to resolve it would help to prioritize the issue.

[anderseknert]

This is a side effect of #6563, but I had no idea about that when I created this issue. Closing this, but hoping that the main issue is prioritized soon as it's making our error messages useless in so many places where they shouldn't be.

Replacing the := with = in the first example will have OPA return an error message relevant to the error.

2 errors occurred:
policy.rego:5: rego_parse_error: illegal string literal: "	foo"
	foo = "	foo"