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,
+ },
+ ],
+ },
  ],
 });