Microsoft/TypeScript

JSDoc comment nodes are not traversed and their parents are sent even if they should not

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#14,575 opened on Mar 10, 2017

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 (3 comments) (1 reaction) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
BugDomain: APIDomain: JSDocHelp Wanted

Description

TypeScript Version: 2.2.1

Code

const ts = require('typescript');

const source = `
/**
 * Some fancy comment
 * 
 * @function sum
 * @param {number} a
 * @param {number} b
 * @returns {number} 
 */
function sum(a: number, b: number): number {
  return a + b;
}
`;

let sourceFile = ts.createSourceFile(
  'input.ts',
  source,
  ts.ScriptTarget.ESNext,
  false // <-- don't set parents
);

ts.forEachChild(sourceFile, function (node) {
  if (node.kind === ts.SyntaxKind.FunctionDeclaration) {
    console.assert(!!node.jsDoc);
    console.assert(node.jsDoc.length === 1);
    console.assert(node.jsDoc[0].parent === undefined);
  } else if (node.kind === ts.SyntaxKind.JSDocComment) {
    console.assert(false);
  }
});

Expected behavior:

  • Expected JSDocComment nodes parents not to be set.
  • Expected JSDocComment nodes to be traversed using forEachChild.

Actual behavior:

When explicitly passing false to createSourceFile for not setting parents in nodes, they are set anyway in all JSDocComment nodes. Also, JSDocComments (and therefore all their children) are not traversed when calling forEachChild. I don't know if that last part is expected behavior, but it is definitely weird that they are not traversed.

Contributor guide

Tech stack
typescript
Domain
tooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Familiarity with TypeScript compilerUnderstanding of AST traversal
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
The issue involves JSDoc comment nodes not being properly handled when setParent is false. Investigate the createSourceFile function in the TypeScript compiler source (src/compiler/parser.ts) to see how parents are set on JSDoc nodes. Also examine the forEachChild function to understand why JSDoc nodes are not traversed. Look for any existing tests related to JSDoc traversal. The fix may involve ensuring that when setParent is false, JSDoc nodes also have their parent set undefined, and that forEachChild includes JSDoc nodes.