From a10d09fababffb1049b342957d79883705257013 Mon Sep 17 00:00:00 2001 From: Linus Groh Date: Thu, 29 Oct 2020 18:11:35 +0000 Subject: [PATCH] LibJS: Tweak generated source in 'new Function()' to match ES 2015 spec 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. --- .../LibJS/Runtime/FunctionConstructor.cpp | 2 +- .../LibJS/Tests/builtins/Function/Function.js | 4 +++- .../LibJS/Tests/parser-line-terminators.js | 18 ++++++++++++------ 3 files changed, 16 insertions(+), 8 deletions(-) diff --git a/Libraries/LibJS/Runtime/FunctionConstructor.cpp b/Libraries/LibJS/Runtime/FunctionConstructor.cpp index 7b269269c0..b8664907f2 100644 --- a/Libraries/LibJS/Runtime/FunctionConstructor.cpp +++ b/Libraries/LibJS/Runtime/FunctionConstructor.cpp @@ -81,7 +81,7 @@ Value FunctionConstructor::construct(Function&) if (vm.exception()) return {}; } - auto source = String::formatted("function anonymous({}) {{ {} }}", parameters_source, body_source); + auto source = String::formatted("function anonymous({}\n) {{\n{}\n}}", parameters_source, body_source); auto parser = Parser(Lexer(source)); auto function_expression = parser.parse_function_node(); if (parser.has_errors()) { diff --git a/Libraries/LibJS/Tests/builtins/Function/Function.js b/Libraries/LibJS/Tests/builtins/Function/Function.js index 2076968ae1..9a972ab81d 100644 --- a/Libraries/LibJS/Tests/builtins/Function/Function.js +++ b/Libraries/LibJS/Tests/builtins/Function/Function.js @@ -30,6 +30,8 @@ describe("correct behavior", () => { expect(new Function("return typeof Function()")()).toBe("function"); expect(new Function("x", "return function (y) { return x + y };")(1)(2)).toBe(3); + expect(new Function("-->")()).toBeUndefined(); + expect(new Function().name).toBe("anonymous"); expect(new Function().toString()).toBe("function anonymous() {\n ???\n}"); }); @@ -45,7 +47,7 @@ describe("errors", () => { // This is in line with what other engines are reporting. .toThrowWithMessage( SyntaxError, - "Unexpected token CurlyClose. Expected BracketClose (line: 1, column: 26)" + "Unexpected token CurlyClose. Expected BracketClose (line: 4, column: 1)" ); }); }); diff --git a/Libraries/LibJS/Tests/parser-line-terminators.js b/Libraries/LibJS/Tests/parser-line-terminators.js index 5a12195821..ab88b0eb44 100644 --- a/Libraries/LibJS/Tests/parser-line-terminators.js +++ b/Libraries/LibJS/Tests/parser-line-terminators.js @@ -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( +) { + +} ⚠ 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", () => {