Negative column with multi-line string literal

[lahma]

When parsing a multi-line string literal that has windows line feeds (\r\n) a negative column number is produced.

Steps to reproduce

var tree = esprima.parseScript("var str = 'test \\\r\nd'+'test \\\r\ntest'+'f';", { loc: true });
tree["body"][0].declarations[0].init.left.loc
JSON.stringify(tree["body"][0].declarations[0].init.left.loc)

Expected output

{"start":{"line":1,"column":10},"end":{"line":3,"column":5}}

Actual output

{"start":{"line":1,"column":-9},"end":{"line":3,"column":5}}

Relevant references

I see there's been such problem before too: #1844

[lahma]

I think the problem is here:

esprima/src/parser.ts

Lines 1514 to 1521 in d277380

	while ((stack.length > 2) && (prec <= precedences[precedences.length - 1])) {
	right = stack.pop();
	const operator = stack.pop();
	precedences.pop();
	left = stack.pop();
	markers.pop();
	const node = this.startNode(markers[markers.length - 1]);
	stack.push(this.finalize(node, new Node.BinaryExpression(operator, left, right)));

This code path doesn't check for the popped marker and use its lineStart as lastLineStart for startNode call like the code below it does:

esprima/src/parser.ts

Lines 1536 to 1544 in d277380

	while (i > 1) {
	const marker = markers.pop();
	const lastLineStart = lastMarker && lastMarker.lineStart;
	const node = this.startNode(marker, lastLineStart);
	const operator = stack[i - 1];
	expr = this.finalize(node, new Node.BinaryExpression(operator, stack[i - 2], expr));
	i -= 2;
	lastMarker = marker;
	}

I see that tests are explicitly checked not to contain windows line feeds so I'm unsure how to create a PR for this.

[lahma]

Created PR #2033

[lahma]

ping @ariya 🙂

[KFlash]

There already exist issues and PR"s created years back that he haven't responded too yet. Expect him to be a slow replier.

[lahma]

And it's all fine, I understand that when it's free work one can choose his priorities. I just have some wishful thinking to verify the approach to get that on .NET version's side where we actually throw an error when we encounter invalid index values.