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LibJS: Tweak generated source in 'new Function()' to match ES 2015 spec

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ES 5(.1) described parsing of the function body string as:

https://www.ecma-international.org/ecma-262/5.1/#sec-15.3.2.1

7. If P is not parsable as a FormalParameterList[opt] then throw a SyntaxError exception.
8. If body is not parsable as FunctionBody then throw a SyntaxError exception.

We implemented it as building the source string of a complete function
and feeding that to the parser, with the same outcome. ES 2015+ does
exactly that, but with newlines at certain positions:

https://tc39.es/ecma262/#sec-createdynamicfunction

16. Let bodyString be the string-concatenation of 0x000A (LINE FEED), ? ToString(bodyArg), and 0x000A (LINE FEED).
17. Let prefix be the prefix associated with kind in Table 49.
18. Let sourceString be the string-concatenation of prefix, " anonymous(", P, 0x000A (LINE FEED), ") {", bodyString, and "}".

This patch updates the generated source string to match these
requirements. This will make certain edge cases work, e.g.
'new Function("-->")', where the user supplied input must be placed on
its own line to be valid syntax.
This commit is contained in:
Linus Groh 2020-10-29 18:11:35 +00:00 • committed by Andreas Kling
parent bed270ca47
commit a10d09faba
3 changed files with 16 additions and 8 deletions
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18
Libraries/LibJS/Tests/parser-line-terminators.js
View file

@ -1,5 +1,11 @@
/*
These tests deliberately produce syntax errors to check what line the parser thinks we're on.
Note that line numbers are higher than you might expect as the parsed code is:
function anonymous(
) {
<code>
}
⚠ PLEASE MAKE SURE TO NOT LET YOUR EDITOR REMOVE THE LS/PS LINE TERMINATORS!
*/
@ -7,31 +13,31 @@ These tests deliberately produce syntax errors to check what line the parser thi
test("LINE FEED is a line terminator", () => {
expect(() => {
Function("\n\n@");
}).toThrowWithMessage(SyntaxError, "line: 3, column: 1");
}).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
});
test("CARRIAGE RETURN is a line terminator", () => {
expect(() => {
Function("\r\r@");
}).toThrowWithMessage(SyntaxError, "line: 3, column: 1");
}).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
});
test("LINE SEPARATOR is a line terminator", () => {
expect(() => {
Function("

@");
}).toThrowWithMessage(SyntaxError, "line: 3, column: 1");
}).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
});
test("PARAGRAPH SEPARATOR is a line terminator", () => {
expect(() => {
Function("

@");
}).toThrowWithMessage(SyntaxError, "line: 3, column: 1");
}).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
});
test("CR LF is counted as only one line terminator", () => {
expect(() => {
Function("\r\n\r\n@");
}).toThrowWithMessage(SyntaxError, "line: 3, column: 1");
}).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
});
test("LF/CR are not allowed in string literal", () => {
@ -49,7 +55,7 @@ test("LS/PS are allowed in string literal", () => {
test("line terminators can be mixed (but please don't)", () => {
expect(() => {
Function("\r
\r\n
\n\r@");
}).toThrowWithMessage(SyntaxError, "line: 7, column: 1");
}).toThrowWithMessage(SyntaxError, "line: 9, column: 1");
});
test("all line terminators are valid for line continuations", () => {