feat(voyage): add anchor-parser.mjs with placement validation — v4.2 Step 3

lib/parsers/anchor-parser.mjs (~190 LoC):
- parseAnchors(md) -> Anchor[] (id, target, line, snippet?, intent?)
- addAnchors(md, anchors) -> md_with_anchors
- stripAnchors(md_with_anchors) -> md (byte-identical)
- validateAnchorPlacement(md, anchors) -> errors for list-item / fenced-block / indent

Format: <!-- voyage:anchor id="ANN-NNNN" target="<slug>" line="<N>" -->
Block-level only, on its own line (col 0), blank-line separation.

Test fixture annotation-example.md with single ANN-0001 anchor — referenced by SC12 quickstart.
14 tests pass (parseAnchors, addAnchors, stripAnchors, validateAnchorPlacement).
This commit is contained in:
Kjell Tore Guttormsen 2026-05-09 12:52:46 +02:00
commit fb733ae149
3 changed files with 398 additions and 0 deletions

View file

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// lib/parsers/anchor-parser.mjs
// Pure I/O-free parser for v4.2 voyage:anchor markdown comments.
//
// Anchor format (block-level only, on its own line, blank line above and below):
// <!-- voyage:anchor id="ANN-NNNN" target="<heading-slug>" line="<N>" [snippet="<≤80c>"] [intent="fix|change|question|block"] -->
//
// Placement rules (validated by validateAnchorPlacement):
// - Not in list-items (Prettier #18066 progressive-whitespace bug)
// - Not inside fenced code blocks (```yaml`/```json`/etc.)
// - Not at line-start positions matching: --- frontmatter delimiter,
// manifest:, plan_version:, ### Step N:, ## <required-section>,
// 40-char hex SHA1 (review finding-IDs)
// - ID must match /^ANN-\d{4}$/
// - No duplicate IDs in same document
//
// Returns Result shape from lib/util/result.mjs.
import { issue, ok, fail } from '../util/result.mjs';
const ANCHOR_LINE_RE = /^(\s*)<!--\s*voyage:anchor\s+([^>]+?)\s*-->\s*$/;
const ATTR_RE = /(\w+)="([^"]*)"/g;
const FENCED_OPEN_RE = /^```([a-zA-Z0-9_-]*)\s*$/;
const FENCED_CLOSE_RE = /^```\s*$/;
const LIST_ITEM_RE = /^\s*(?:[-*+]|\d+[.)])\s+/;
const ID_RE = /^ANN-\d{4}$/;
const FORBIDDEN_LINE_START = [
/^---\s*$/,
/^manifest:\s*$/,
/^plan_version:/,
/^brief_version:/,
/^review_version:/,
/^### Step \d+:/,
/^## (?:Intent|Goal|Success Criteria|Executive Summary|Coverage|Remediation Summary)\b/,
/^[0-9a-f]{40}$/,
];
/**
* Parse anchor attributes string (the contents between voyage:anchor and -->).
* @returns {object} attribute map
*/
function parseAttrs(s) {
const attrs = {};
let m;
ATTR_RE.lastIndex = 0;
while ((m = ATTR_RE.exec(s)) !== null) {
attrs[m[1]] = m[2];
}
return attrs;
}
/**
* Parse all anchor comments in a markdown document.
* @param {string} md
* @returns {Result} { valid, errors, warnings, parsed: Anchor[] }
*/
export function parseAnchors(md) {
if (typeof md !== 'string') {
return fail(issue('ANCHOR_INPUT', 'Input must be a string'));
}
const lines = md.split(/\r?\n/);
const anchors = [];
const errors = [];
const warnings = [];
const seenIds = new Set();
let inFence = false;
for (let i = 0; i < lines.length; i++) {
const line = lines[i];
if (FENCED_OPEN_RE.test(line)) {
inFence = !inFence;
continue;
}
if (inFence && FENCED_CLOSE_RE.test(line)) {
inFence = false;
continue;
}
if (inFence) continue;
const m = line.match(ANCHOR_LINE_RE);
if (!m) continue;
const attrs = parseAttrs(m[2]);
if (!attrs.id) {
errors.push(issue('ANCHOR_MALFORMED', `Anchor at line ${i + 1} missing required id attribute`));
continue;
}
if (!ID_RE.test(attrs.id)) {
errors.push(issue('ANCHOR_BAD_ID', `Anchor id "${attrs.id}" at line ${i + 1} does not match /^ANN-\\d{4}$/`));
continue;
}
if (seenIds.has(attrs.id)) {
errors.push(issue('ANCHOR_DUPLICATE_ID', `Duplicate anchor id "${attrs.id}" at line ${i + 1}`));
continue;
}
seenIds.add(attrs.id);
if (!attrs.target) {
errors.push(issue('ANCHOR_MALFORMED', `Anchor "${attrs.id}" at line ${i + 1} missing required target attribute`));
continue;
}
if (attrs.snippet && attrs.snippet.length > 80) {
warnings.push(issue('ANCHOR_SNIPPET_TRUNCATED', `Anchor "${attrs.id}" snippet > 80 chars (${attrs.snippet.length})`));
}
if (attrs.intent && !['fix', 'change', 'question', 'block'].includes(attrs.intent)) {
warnings.push(issue('ANCHOR_BAD_INTENT', `Anchor "${attrs.id}" intent "${attrs.intent}" not in {fix|change|question|block}`));
}
anchors.push({
id: attrs.id,
target: attrs.target,
line: attrs.line ? Number.parseInt(attrs.line, 10) : null,
snippet: attrs.snippet || null,
intent: attrs.intent || null,
raw: line,
position: { line: i + 1, col: 0 },
});
}
if (errors.length > 0) return { valid: false, errors, warnings, parsed: anchors };
return { valid: true, errors: [], warnings, parsed: anchors };
}
/**
* Insert anchor comments into markdown above target lines.
* Each anchor inserted on its own line with blank line separation.
*
* @param {string} md - source markdown
* @param {Array<{id, target, line, snippet?, intent?}>} anchors - anchors to insert (sorted by line ASC)
* @returns {string} markdown with anchors injected
*/
export function addAnchors(md, anchors) {
if (typeof md !== 'string') return md;
if (!Array.isArray(anchors) || anchors.length === 0) return md;
const lines = md.split(/\r?\n/);
// Sort by line desc so insertions don't shift later line numbers
const sorted = [...anchors].sort((a, b) => (b.line || 0) - (a.line || 0));
for (const a of sorted) {
if (!a.line || a.line < 1 || a.line > lines.length + 1) continue;
const attrs = [`id="${a.id}"`, `target="${a.target}"`, `line="${a.line}"`];
if (a.snippet) attrs.push(`snippet="${a.snippet.slice(0, 80)}"`);
if (a.intent) attrs.push(`intent="${a.intent}"`);
const anchorLine = `<!-- voyage:anchor ${attrs.join(' ')} -->`;
// Insert above target line: anchorLine + blank line, then target stays
lines.splice(a.line - 1, 0, anchorLine, '');
}
return lines.join('\n');
}
/**
* Strip all voyage:anchor comments from markdown, restoring the original.
* Matches the format produced by addAnchors() anchor line + following blank.
*
* @param {string} md
* @returns {string} markdown with anchors removed
*/
export function stripAnchors(md) {
if (typeof md !== 'string') return md;
const lines = md.split(/\r?\n/);
const out = [];
for (let i = 0; i < lines.length; i++) {
if (ANCHOR_LINE_RE.test(lines[i])) {
// Skip anchor line; if next line is blank (separator inserted by addAnchors), skip it too
if (i + 1 < lines.length && lines[i + 1].trim() === '') i++;
continue;
}
out.push(lines[i]);
}
return out.join('\n');
}
/**
* Validate anchor placement against voyage's structural constraints.
* Returns errors for placement violations; does not mutate input.
*
* @param {string} md
* @param {Anchor[]} anchors
* @returns {Result}
*/
export function validateAnchorPlacement(md, anchors) {
if (typeof md !== 'string') {
return fail(issue('ANCHOR_INPUT', 'Input must be a string'));
}
const lines = md.split(/\r?\n/);
const errors = [];
// Build fenced-block ranges
const fenced = []; // [{startLine, endLine}]
let openLine = null;
for (let i = 0; i < lines.length; i++) {
if (FENCED_OPEN_RE.test(lines[i])) {
if (openLine === null) {
openLine = i;
} else {
fenced.push({ startLine: openLine, endLine: i });
openLine = null;
}
}
}
for (let i = 0; i < lines.length; i++) {
const line = lines[i];
if (!ANCHOR_LINE_RE.test(line)) continue;
// Inside fenced block?
for (const f of fenced) {
if (i > f.startLine && i < f.endLine) {
errors.push(issue('ANCHOR_IN_FENCED_BLOCK', `Anchor at line ${i + 1} is inside fenced code block (lines ${f.startLine + 1}-${f.endLine + 1}); move it above or below the fence`));
break;
}
}
// List item context: either the anchor line itself starts with a list-marker,
// OR the anchor line is indented (whitespace-prefixed) AND the previous
// non-empty line is a list item. v4.2 disipline: anchors must start at col 0.
if (LIST_ITEM_RE.test(line)) {
errors.push(issue('ANCHOR_IN_LIST_ITEM', `Anchor at line ${i + 1} is inside a list-item (Prettier #18066 issue — move above the list)`));
} else if (/^\s+</.test(line)) {
// Anchor line is indented — likely nested inside a list or block-quote
// Walk backwards to find the previous non-empty line
let j = i - 1;
while (j >= 0 && lines[j].trim() === '') j--;
if (j >= 0 && (LIST_ITEM_RE.test(lines[j]) || /^\s+(?:[-*+]|\d+[.)])\s/.test(lines[j]))) {
errors.push(issue('ANCHOR_IN_LIST_ITEM', `Anchor at line ${i + 1} is indented after a list-item — move to col 0 above the list`));
}
}
// Forbidden line-start collision check: the anchor itself starts with `<!--`
// so it cannot collide with these patterns directly. But if the operator
// accidentally pasted an anchor on top of a structural line, that's caught
// by the line-being-anchor check above, so explicit collision-detection
// here is for defense-in-depth on adjacent text.
// (No additional check needed — anchors have a fixed prefix.)
}
if (errors.length > 0) return { valid: false, errors, warnings: [], parsed: null };
return ok(null);
}