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fix(loader): uncontrolled string concatenation leads to max call stack exceeded #690

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fix(loader): uncontrolled string concatenation leads to max call stack exceeded #690

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ced2c0d
fix(loader): uncontrolled string concatenation leads to max call stac…
Gobie Mar 7, 2018
a05e9d3
fix(tests): increase urlConcat timeout as it can take long time to co…
Gobie Mar 7, 2018
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15 changes: 10 additions & 5 deletions lib/loader.js
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Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,12 @@ module.exports = function(content, map) {
if(query.url !== false && result.urlItems.length > 0) {
urlEscapeHelper = "var escape = require(" + loaderUtils.stringifyRequest(this, require.resolve("./url/escape.js")) + ");\n";

var concatPatternCnt = 0;
cssAsString = cssAsString.replace(result.urlItemRegExpG, function(item) {
// split concat pattern "" + ... + "" -> ("" + ... + "") + ("" + ... + "") to avoid maximum call stack exceeded error
concatPatternCnt += 1
var concatPattern = concatPatternCnt % 1000 === 0 ? ") + (" : " + "

var match = result.urlItemRegExp.exec(item);
var idx = +match[1];
var urlItem = result.urlItems[idx];
Expand All @@ -101,14 +106,14 @@ module.exports = function(content, map) {
if(idx > 0) { // idx === 0 is catched by isUrlRequest
// in cases like url('webfont.eot?#iefix')
urlRequest = url.substr(0, idx);
return "\" + escape(require(" + loaderUtils.stringifyRequest(this, urlRequest) + ")) + \"" +
return "\"" + concatPattern + "escape(require(" + loaderUtils.stringifyRequest(this, urlRequest) + ")) + \"" +
url.substr(idx);
}
urlRequest = url;
return "\" + escape(require(" + loaderUtils.stringifyRequest(this, urlRequest) + ")) + \"";
return "\"" + concatPattern + "escape(require(" + loaderUtils.stringifyRequest(this, urlRequest) + ")) + \"";
}.bind(this));
}

var exportJs = compileExports(result, importItemMatcher.bind(this), camelCaseKeys);
if (exportJs) {
exportJs = "exports.locals = " + exportJs + ";";
Expand All @@ -126,9 +131,9 @@ module.exports = function(content, map) {
}
map.file = map.file.split("!").pop().replace(/\\/g, '/');
map = JSON.stringify(map);
moduleJs = "exports.push([module.id, " + cssAsString + ", \"\", " + map + "]);";
moduleJs = "exports.push([module.id, (" + cssAsString + "), \"\", " + map + "]);";
} else {
moduleJs = "exports.push([module.id, " + cssAsString + ", \"\"]);";
moduleJs = "exports.push([module.id, (" + cssAsString + "), \"\"]);";
}

// embed runtime
Expand Down
28 changes: 28 additions & 0 deletions test/urlConcatTest.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
/*globals describe */

var helpers = require("./helpers");
var test = helpers.test;

describe("url concat", function() {
this.timeout(10000);

var actualCSS, expectedCSS, i;

actualCSS = '';
expectedCSS = '';
for (i = 0; i < 100; i++) {
actualCSS += ".class" + i + " { background-image: url(./path/to/file.png); }";
expectedCSS += ".class" + i + " { background-image: url({./path/to/file.png}); }";
}

test("should handle concat of 201 strings", actualCSS, [[1, expectedCSS, ""]]);

actualCSS = '';
expectedCSS = '';
for (i = 0; i < 10000; i++) {
actualCSS += ".class" + i + " { background-image: url(./path/to/file.png); }";
expectedCSS += ".class" + i + " { background-image: url({./path/to/file.png}); }";
}

test("should handle concat of 20001 strings", actualCSS, [[1, expectedCSS, ""]]);
});