ignore invalid mappings when reading a source map

Author: sokra

lib/helpers/__mocks__/createMappingsSerializer.js

@@ -7,7 +7,7 @@ const createMappingsSerializer = jest.requireActual(
 module.exports = options => {
 	const fn = createMappingsSerializer(options);
 	let lastLine = 1;
-	let lastColumn = 0;
+	let lastColumn = -1;
 	return (
 		generatedLine,
 		generatedColumn,
@@ -18,7 +18,7 @@ module.exports = options => {
 	) => {
 		if (
 			generatedLine >= lastLine &&
-			generatedColumn >= (generatedLine === lastLine ? lastColumn : 0) &&
+			generatedColumn > (generatedLine === lastLine ? lastColumn : -1) &&
 			(sourceIndex === -1
 				? originalLine === -1 && originalColumn === -1 && nameIndex === -1
 				: sourceIndex >= 0 &&
@@ -38,8 +38,8 @@ module.exports = options => {
 			);
 		}
 		throw new Error(`Invalid mapping passed to mapping serializer:
-generatedLine = ${generatedLine},
-generatedColumn = ${generatedColumn},
+generatedLine = ${generatedLine} (lastLine = ${lastLine}),
+generatedColumn = ${generatedColumn} (lastColumn = ${lastColumn}),
 sourceIndex = ${sourceIndex},
 originalLine = ${originalLine},
 originalColumn = ${originalColumn},

lib/helpers/readMappings.js

@@ -38,38 +38,43 @@ const readMappings = (mappings, onMapping) => {
 	let currentValue = 0;
 	let currentValuePos = 0;
 	let generatedLine = 1;
+	let generatedColumn = -1;
 	for (let i = 0; i < mappings.length; i++) {
 		const cc = mappings.charCodeAt(i);
 		if (cc > ccMax) continue;
 		const value = ccToValue[cc];
 		if ((value & END_SEGMENT_BIT) !== 0) {
 			// End current segment
-			if (currentDataPos === 1) {
-				onMapping(generatedLine, currentData[0], -1, -1, -1, -1);
-			} else if (currentDataPos === 4) {
-				onMapping(
-					generatedLine,
-					currentData[0],
-					currentData[1],
-					currentData[2],
-					currentData[3],
-					-1
-				);
-			} else if (currentDataPos === 5) {
-				onMapping(
-					generatedLine,
-					currentData[0],
-					currentData[1],
-					currentData[2],
-					currentData[3],
-					currentData[4]
-				);
+			if (currentData[0] > generatedColumn) {
+				if (currentDataPos === 1) {
+					onMapping(generatedLine, currentData[0], -1, -1, -1, -1);
+				} else if (currentDataPos === 4) {
+					onMapping(
+						generatedLine,
+						currentData[0],
+						currentData[1],
+						currentData[2],
+						currentData[3],
+						-1
+					);
+				} else if (currentDataPos === 5) {
+					onMapping(
+						generatedLine,
+						currentData[0],
+						currentData[1],
+						currentData[2],
+						currentData[3],
+						currentData[4]
+					);
+				}
+				generatedColumn = currentData[0];
 			}
 			currentDataPos = 0;
 			if (value === NEXT_LINE) {
 				// Start new line
 				generatedLine++;
 				currentData[0] = 0;
+				generatedColumn = -1;
 			}
 		} else if ((value & CONTINUATION_BIT) === 0) {
 			// last sextet

package.json

@@ -6,7 +6,7 @@
   "scripts": {
     "pretest": "yarn lint",
     "test": "jest",
-    "lint": "eslint --cache lib test",
+    "lint": "eslint --cache lib test/*.js",
     "cover": "jest --coverage"
   },
   "devDependencies": {

test/SourceMapSource.js

@@ -4,6 +4,8 @@ const OriginalSource = require("../").OriginalSource;
 const ConcatSource = require("../").ConcatSource;
 const ReplaceSource = require("../").ReplaceSource;
 const SourceNode = require("source-map").SourceNode;
+const fs = require("fs");
+const path = require("path");
 const { withReadableMappings } = require("./helpers");
 
 describe("SourceMapSource", () => {
@@ -207,4 +209,21 @@ describe("SourceMapSource", () => {
 		}
 	`);
 	});
+
+	it("should handle es6-promise correctly", () => {
+		const code = fs.readFileSync(
+			path.resolve(__dirname, "fixtures", "es6-promise.js"),
+			"utf-8"
+		);
+		const map = JSON.parse(
+			fs.readFileSync(
+				path.resolve(__dirname, "fixtures", "es6-promise.map"),
+				"utf-8"
+			)
+		);
+		const inner = new SourceMapSource(code, "es6-promise.js", map);
+		const source = new ConcatSource(inner, inner);
+		expect(source.source()).toBe(code + code);
+		expect(source.sourceAndMap().source).toBe(code + code);
+	});
 });