fix: no-missing-label-refs should not crash on undefined labels (#290)

* fix: no-missing-label-refs should not crash on undefined labels Fixes #289 * fix locations * add a note to function `findOffsets` * add a comment for the loop * add a comment for the regex
eslint · Oct 16, 2024 · ac1bc1c · ac1bc1c
1 parent 9c92c9f
commit ac1bc1c
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diff --git a/src/rules/no-missing-label-refs.js b/src/rules/no-missing-label-refs.js
@@ -21,106 +21,77 @@ import { findOffsets, illegalShorthandTailPattern } from "../util.js";
 // Helpers
 //-----------------------------------------------------------------------------
 
-const labelPatterns = [
-	// [foo][bar]
-	/\]\[([^\]]+)\]/u,
-
-	// [foo][]
-	/(\]\[\])/u,
-
-	// [foo]
-	/\[([^\]]+)\]/u,
-];
-
-const shorthandTailPattern = /\]\[\]$/u;
-
 /**
  * Finds missing references in a node.
  * @param {TextNode} node The node to check.
- * @param {string} docText The text of the node.
+ * @param {string} nodeText The text of the node.
  * @returns {Array<{label:string,position:Position}>} The missing references.
  */
-function findMissingReferences(node, docText) {
+function findMissingReferences(node, nodeText) {
 	const missing = [];
-	let startIndex = 0;
-	const offset = node.position.start.offset;
 	const nodeStartLine = node.position.start.line;
 	const nodeStartColumn = node.position.start.column;
 
 	/*
-	 * This loop works by searching the string inside the node for the next
-	 * label reference. If there is, it reports an error.
-	 * It then moves the start index to the end of the label reference and
-	 * continues searching the text until the end of the text is found.
+	 * Matches substrings like "[foo]", "[]", "[foo][bar]", "[foo][]", "[][bar]", or "[][]".
+	 * `left` is the content between the first brackets. It can be empty.
+	 * `right` is the content between the second brackets. It can be empty, and it can be undefined.
 	 */
-	while (startIndex < node.value.length) {
-		const value = node.value.slice(startIndex);
+	const labelPattern = /\[(?<left>[^\]]*)\](?:\[(?<right>[^\]]*)\])?/dgu;
 
-		const match = labelPatterns.reduce((previous, pattern) => {
-			if (previous) {
-				return previous;
-			}
-
-			return value.match(pattern);
-		}, null);
-
-		// check for array instead of null to appease TypeScript
-		if (!Array.isArray(match)) {
-			break;
-		}
+	let match;
 
+	/*
+	 * This loop searches the text inside the node for sequences that
+	 * look like label references and reports an error for each one found.
+	 */
+	while ((match = labelPattern.exec(nodeText))) {
 		// skip illegal shorthand tail -- handled by no-invalid-label-refs
 		if (illegalShorthandTailPattern.test(match[0])) {
-			startIndex += match.index + match[0].length;
 			continue;
 		}
 
-		// Calculate the match index relative to just the node.
-		let columnStart = startIndex + match.index;
-		let label = match[1];
-
-		// need to look backward to get the label
-		if (shorthandTailPattern.test(match[0])) {
-			// adding 1 to the index just in case we're in a ![] and need to skip the !.
-			const startFrom = offset + startIndex + 1;
-			const lastOpenBracket = docText.lastIndexOf("[", startFrom);
-
-			if (lastOpenBracket === -1) {
-				startIndex += match.index + match[0].length;
-				continue;
-			}
-
-			label = docText
-				.slice(lastOpenBracket, match.index + match[0].length)
-				.match(/!?\[([^\]]+)\]/u)?.[1];
-			columnStart -= label.length;
-		} else if (match[0].startsWith("]")) {
-			columnStart += 2;
+		const { left, right } = match.groups;
+
+		// `[][]` or `[]`
+		if (!left && !right) {
+			continue;
+		}
+
+		let label, labelIndices;
+
+		if (right) {
+			label = right;
+			labelIndices = match.indices.groups.right;
 		} else {
-			columnStart += 1;
+			label = left;
+			labelIndices = match.indices.groups.left;
 		}
 
 		const { lineOffset: startLineOffset, columnOffset: startColumnOffset } =
-			findOffsets(node.value, columnStart);
-
-		const startLine = nodeStartLine + startLineOffset;
-		const startColumn = nodeStartColumn + startColumnOffset;
+			findOffsets(nodeText, labelIndices[0]);
+		const { lineOffset: endLineOffset, columnOffset: endColumnOffset } =
+			findOffsets(nodeText, labelIndices[1]);
 
 		missing.push({
 			label: label.trim(),
 			position: {
 				start: {
-					line: startLine,
-					column: startColumn,
+					line: nodeStartLine + startLineOffset,
+					column:
+						startLineOffset > 0
+							? startColumnOffset + 1
+							: nodeStartColumn + startColumnOffset,
 				},
 				end: {
-					line: startLine,
-					column: startColumn + label.length,
+					line: nodeStartLine + endLineOffset,
+					column:
+						endLineOffset > 0
+							? endColumnOffset + 1
+							: nodeStartColumn + endColumnOffset,
 				},
 			},
 		});
-
-		startIndex += match.index + match[0].length;
 	}
 
 	return missing;
@@ -164,7 +135,7 @@ export default {
 
 			text(node) {
 				allMissingReferences.push(
-					...findMissingReferences(node, sourceCode.text),
+					...findMissingReferences(node, sourceCode.getText(node)),
 				);
 			},
 

diff --git a/src/util.js b/src/util.js
@@ -15,6 +15,9 @@ export const illegalShorthandTailPattern = /\]\[\s+\]$/u;
  * @param {string} text The text to search.
  * @param {number} offset The offset to find.
  * @returns {{lineOffset:number,columnOffset:number}} The location of the offset.
+ *      Note that `columnOffset` should be used as an offset to the column number
+ *      of the given text in the source code only when `lineOffset` is 0.
+ *      Otherwise, it should be used as a 0-based column number in the source code.
  */
 export function findOffsets(text, offset) {
 	let lineOffset = 0;

diff --git a/tests/rules/no-missing-label-refs.test.js b/tests/rules/no-missing-label-refs.test.js
@@ -35,6 +35,15 @@ ruleTester.run("no-missing-label-refs", rule, {
 		"[  foo ][]\n\n[foo]: http://bar.com/image.jpg",
 		"[foo][ ]\n\n[foo]: http://bar.com/image.jpg",
 		"[\nfoo\n][\n]\n\n[foo]: http://bar.com/image.jpg",
+		"[]",
+		"][]",
+		"[][]",
+		"[] []",
+		"[foo",
+		"foo]",
+		"foo][bar]\n\n[bar]: http://bar.com",
+		"foo][bar][baz]\n\n[baz]: http://baz.com",
+		"[][foo]\n\n[foo]: http://foo.com",
 	],
 	invalid: [
 		{
@@ -149,5 +158,178 @@ ruleTester.run("no-missing-label-refs", rule, {
 				},
 			],
 		},
+		{
+			code: "foo][bar]\n\n[baz]: http://baz.com",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "bar" },
+					line: 1,
+					column: 6,
+					endLine: 1,
+					endColumn: 9,
+				},
+			],
+		},
+		{
+			code: "foo][bar][baz]\n\n[bar]: http://bar.com",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "baz" },
+					line: 1,
+					column: 11,
+					endLine: 1,
+					endColumn: 14,
+				},
+			],
+		},
+		{
+			code: "[foo]\n[foo][bar]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "foo" },
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 5,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "bar" },
+					line: 2,
+					column: 7,
+					endLine: 2,
+					endColumn: 10,
+				},
+			],
+		},
+		{
+			code: "[Foo][foo]\n[Bar][]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "foo" },
+					line: 1,
+					column: 7,
+					endLine: 1,
+					endColumn: 10,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "Bar" },
+					line: 2,
+					column: 2,
+					endLine: 2,
+					endColumn: 5,
+				},
+			],
+		},
+		{
+			code: "[Foo][]\n[Bar][]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "Foo" },
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 5,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "Bar" },
+					line: 2,
+					column: 2,
+					endLine: 2,
+					endColumn: 5,
+				},
+			],
+		},
+		{
+			code: "[Foo][foo]\n[Bar][bar]\n[Hoge][]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "foo" },
+					line: 1,
+					column: 7,
+					endLine: 1,
+					endColumn: 10,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "bar" },
+					line: 2,
+					column: 7,
+					endLine: 2,
+					endColumn: 10,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "Hoge" },
+					line: 3,
+					column: 2,
+					endLine: 3,
+					endColumn: 6,
+				},
+			],
+		},
+		{
+			code: "[Foo][]\n[Bar][bar]\n[Hoge][hoge]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "Foo" },
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 5,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "bar" },
+					line: 2,
+					column: 7,
+					endLine: 2,
+					endColumn: 10,
+				},
+				{
+					messageId: "notFound",
+					data: { label: "hoge" },
+					line: 3,
+					column: 8,
+					endLine: 3,
+					endColumn: 12,
+				},
+			],
+		},
+		{
+			code: "[][foo]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "foo" },
+					line: 1,
+					column: 4,
+					endLine: 1,
+					endColumn: 7,
+				},
+			],
+		},
+		{
+			code: " foo\n  [bar]",
+			errors: [
+				{
+					messageId: "notFound",
+					data: { label: "bar" },
+					line: 2,
+					column: 4,
+					endLine: 2,
+					endColumn: 7,
+				},
+			],
+		},
 	],
 });