Filter with 2+ consecutive '&&' operators returns parsing error

[jarangutan]

What is

Trying to do something like:

$.store.book[? @.category == "reference" && @.author == "Nigel Rees" && @.price == 8.95]

will throw out the error:

Error parsing jsonpath: unexpected '&' at position 70

What works

Multiple || operators works, a single || with a && works, but two && back to back blows up. But, you can wrap the second condition in a parenthesis to get it to work:

$.store.book[? @.category == "reference" && (@.author == "Nigel Rees" && @.price == 8.95)]

If you need more && conditions, you would need to do something like this:

$.store.book[? @.category == "reference" && (@.author == "Nigel Rees" && (@.price == 8.95 && @.title == "Sayings of the Century")) ]

What do

I can't tell if this is intentional or not since the RFC doesn't really give much on the && operator. There also isn't a test for this in the compliance test suite.

I'm thinking of cracking open an issue on the compliance test suite to get feedback and add the test if it makes sense.

Would you be cool with me trying my hand at the PR if it turns out the test was missing?

[theory]

I recall seeing this oddness while I developed this package, but thought it was inherent in the RFC. Yet looking at serde JSON Path, on which I based this implementation, it doesn't have this issue; it's fine with this query:

$.store.books[? @.category == "reference" && @.author == "Jared Diamond" && @.price == 24.99]

So there must be some flaw in the logic of the parser. Completely agree on adding a test case to the compliance suite and finding out the consensus. I suspect that this is a bug in my implementation. In which case I'd very much welcome a PR. Thank you!

[jg-rp]

Could it be a simple as failing to consume whitespace before && in some cases?

Your example query works if I shove a lex.scanBlankSpace() at the end of this loop.

jsonpath/parser/parse.go

Lines 334 to 345 in ac67e0a

	for lex.r == '&' {
	lex.scan()
	next := lex.scan()
	if next.tok != '&' {
	return nil, makeError(next, fmt.Sprintf("expected '&' but found %v", next.name()))
	}
	expr, err := p.parseBasicExpr()
	if err != nil {
	return nil, err
	}
	ors = append(ors, expr)
	}

As is, manually removing spaces before && works.

$.store.book[? @.category == "reference" && @.author == "Nigel Rees"&& @.price == 8.95]

And test expressions work.

`$.store.book[? @.category && @.author && @.price]`

So it seems like some basic expressions consume trailing whitespace and some don't 🤷‍♂️

[theory]

Well that's embarrassing. Thanks for the analysis, @jg-rp. #25 fixes the issue, and I'll make a release shortly.

And thank you @jarangutan for submitting jsonpath-standard/jsonpath-compliance-test-suite#111. That's such a fantastic resource that will help future developers avoid the same mistakes! :-)