From 499bba129c842c00c1a28d85bc044ab609aee44e Mon Sep 17 00:00:00 2001
From: Joe Mou <dev@mou.fo>
Date: Mon, 21 Sep 2026 17:55:06 -0400
Subject: Add discussions

Discussions are served from GitHub's older server-rendered HTML, with no
embeddedData JSON to read, so the scraper walks the DOM the way the pull
request and wiki code does. A discussion's timeline opens with its own
post and continues with its comments, each carrying its replies nested
inside it, which is where the recursion in _discussionComment.eta comes
from. Categories, upvotes, and the answer a Q&A discussion is marked with
all come along.

Only what GitHub renders up front is shown: neither the next page of
discussions nor the replies it hides behind a "Show N previous replies"
button are fetched, so a comment says how many replies it is missing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 src/app.test.ts     | 156 +++++++++++++++++++++++++++++++++++
 src/app.ts          |  26 ++++++
 src/scraper.test.ts | 131 +++++++++++++++++++++++++++++
 src/scraper.ts      | 232 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 545 insertions(+)

(limited to 'src')

diff --git a/src/app.test.ts b/src/app.test.ts
index 450c1cc..3fdacd5 100644
--- a/src/app.test.ts
+++ b/src/app.test.ts
@@ -358,6 +358,162 @@ describe("wiki", () => {
   });
 });
 
+describe("discussions", () => {
+  const repo = { owner: "jj-vcs", name: "jj" };
+  const categories = [
+    { slug: "general", name: "General", emoji: "\u{1F4AC}" },
+    { slug: "q-a", name: "Q&A", emoji: "\u{1F64F}" },
+  ];
+  const comment = {
+    anchor: "discussioncomment-2258263",
+    author: "martinvonz",
+    createdAt: "2022-02-26T21:56:47Z",
+    labels: ["Maintainer"],
+    bodyHtml: "<p>Good point.</p>",
+    hiddenReason: null,
+    isAnswer: false,
+    replies: [],
+    hiddenReplies: 0,
+  };
+  const discussion = {
+    repo,
+    number: 88,
+    titleHtml: "&quot;at least&quot; .DS_Store was added back",
+    author: "arxanas",
+    category: categories[1],
+    answerAnchor: null,
+    body: { ...comment, anchor: "discussion-3903561", author: "arxanas" },
+    comments: [comment],
+  };
+
+  it("should link every category beside the list", () => {
+    const html = eta.render("discussions.eta", {
+      repo,
+      categories,
+      category: categories[1],
+      discussions: [],
+      q: "hooks",
+    });
+
+    assert.match(html, /href="\/jj-vcs\/jj\/discussions">All<\/a>/);
+    assert.match(html, /href="\/jj-vcs\/jj\/discussions\/categories\/q-a">\u{1F64F} Q&amp;A<\/a>/u);
+    // The search box keeps the query the list was narrowed by.
+    assert.match(html, /<input id="search-input"[^>]*value="hooks">/);
+    assert.match(html, /<option value="discussions" selected>/);
+    assert.match(html, /No discussions found\./);
+  });
+
+  it("should render a row per discussion", () => {
+    const html = eta.render("discussions.eta", {
+      repo,
+      categories,
+      category: null,
+      discussions: [
+        {
+          number: 3549,
+          titleHtml: "Feedback for <code>advance-branches</code>",
+          author: "emesterhazy",
+          createdAt: "2024-04-20T14:32:15Z",
+          category: categories[0],
+          answered: true,
+        },
+      ],
+    });
+
+    assert.match(html, /href="\/jj-vcs\/jj\/discussions\/3549">Feedback for <code>/);
+    assert.match(html, /href="\/jj-vcs\/jj\/discussions\/categories\/general">General<\/a>/);
+    assert.match(html, /<span class="answered pill">Answered<\/span>/);
+    assert.match(html, /<time title="2024-04-20T14:32:15Z">2024-04-20<\/time>/);
+  });
+
+  it("should render the discussion above its comments", () => {
+    const html = eta.render("discussion.eta", discussion);
+
+    assert.match(html, /<title>jj-vcs\/jj - discussions\/88<\/title>/);
+    assert.match(html, /<h2>&quot;at least&quot; \.DS_Store was added back<\/h2>/);
+    assert.match(
+      html,
+      /#88\s+in <a href="\/jj-vcs\/jj\/discussions\/categories\/q-a">Q&amp;A<\/a>/,
+    );
+    // The author is named on the body comment, not in the header.
+    assert.match(html, /<a href="\/arxanas">arxanas<\/a>/);
+    assert.match(html, /<div class="box comment" id="discussion-3903561">/);
+    // The timestamp is the comment's permalink.
+    assert.match(
+      html,
+      /<a href="#discussioncomment-2258263"><time title="2022-02-26T21:56:47Z">2022-02-26<\/time><\/a>/,
+    );
+    assert.match(html, /<div class="box comment" id="discussioncomment-2258263">/);
+    assert.match(html, /<span class="pill">Maintainer<\/span>/);
+  });
+
+  // The answer is called out both in the header, which links down to it, and
+  // on the comment itself.
+  it("should mark the comment that answered the discussion", () => {
+    const html = eta.render("discussion.eta", {
+      ...discussion,
+      answerAnchor: "discussioncomment-2258263",
+      comments: [{ ...comment, isAnswer: true }],
+    });
+
+    assert.match(html, /<a class="answered pill" href="#discussioncomment-2258263">Answered<\/a>/);
+    assert.match(html, /<div class="box comment answer" id="discussioncomment-2258263">/);
+    assert.match(html, /<span class="answered pill">Answer<\/span>/);
+  });
+
+  it("should run replies on from the comment they answer", () => {
+    const html = eta.render("_discussionComment.eta", {
+      comment: {
+        ...comment,
+        hiddenReplies: 5,
+        replies: [{ ...comment, anchor: "discussioncomment-2258264", author: "arxanas" }],
+      },
+    });
+
+    assert.match(
+      html,
+      /<div class="box reply placeholder">\s+5 earlier\s+replies are only on GitHub\./,
+    );
+    assert.match(html, /<div class="box comment reply" id="discussioncomment-2258264">/);
+  });
+
+  // A comment GitHub collapsed has nothing to show but why it was collapsed.
+  it("should render a hidden comment as its reason", () => {
+    const html = eta.render("_discussionComment.eta", {
+      comment: {
+        ...comment,
+        author: null,
+        createdAt: null,
+        labels: [],
+        bodyHtml: "",
+        hiddenReason: "This comment has been hidden.",
+      },
+    });
+
+    assert.match(html, /<div class="box comment" id="discussioncomment-2258263">/);
+    assert.match(html, /<div class="placeholder">This comment has been hidden\.<\/div>/);
+    assert.doesNotMatch(html, /<header>/);
+    assert.doesNotMatch(html, /ghost/);
+  });
+
+  it("should send a discussions search to the discussion list", async () => {
+    const res = await app.request(
+      "http://cgithub.example/jj-vcs/jj/search?q=hooks&type=discussions",
+    );
+
+    assert.strictEqual(res.status, 302);
+    assert.strictEqual(res.headers.get("location"), "/jj-vcs/jj/discussions?discussions_q=hooks");
+  });
+
+  // GitHub's own actions live where a number goes, so they are not ours.
+  it("should only scrape a discussion path that names a number", async () => {
+    const res = await app.request("http://cgithub.example/jj-vcs/jj/discussions/new");
+
+    assert.strictEqual(res.status, 200);
+    assert.match(await res.text(), /url=https:\/\/github.com\/jj-vcs\/jj\/discussions\/new"/);
+  });
+});
+
 describe("global search", () => {
   it("should keep the rest of the query around the qualifier", async () => {
     const res = await app.request(
diff --git a/src/app.ts b/src/app.ts
index 0b9a7e6..ec3680b 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -5,6 +5,8 @@ import { buildCommit } from "./build.generated.ts";
 import {
   getGitHubBlob,
   getGitHubCommits,
+  getGitHubDiscussion,
+  getGitHubDiscussions,
   getGitHubIssues,
   getGitHubSidebar,
   getGitHubLatestCommit,
@@ -218,6 +220,28 @@ export function createApp(eta: Eta) {
     return c.render("pulls.eta", await getGitHubPulls(owner, repo, { q }));
   });
 
+  app.get("/:owner/:repo/discussions", async (c) => {
+    const { owner, repo } = c.req.param();
+    const q = c.req.query("discussions_q");
+    return c.render("discussions.eta", await getGitHubDiscussions(owner, repo, { q }));
+  });
+
+  app.get("/:owner/:repo/discussions/categories/:category", async (c) => {
+    const { owner, repo, category } = c.req.param();
+    const q = c.req.query("discussions_q");
+    return c.render("discussions.eta", await getGitHubDiscussions(owner, repo, { q, category }));
+  });
+
+  // GitHub puts its own actions (new, categories, ...) where a number goes, so
+  // anything that isn't one is not a discussion of ours to render.
+  app.get("/:owner/:repo/discussions/:number", async (c) => {
+    const { owner, repo, number } = c.req.param();
+    if (!/^\d+$/.test(number)) {
+      return redirectToGitHub(c);
+    }
+    return c.render("discussion.eta", await getGitHubDiscussion(owner, repo, Number(number)));
+  });
+
   app.get("/:owner/:repo/search", async (c) => {
     const { owner, repo } = c.req.param();
     const q = c.req.query("q") ?? "";
@@ -227,6 +251,8 @@ export function createApp(eta: Eta) {
       return c.redirect(`/${owner}/${repo}/issues?q=${encodeURIComponent(q)}`);
     } else if (type === "pullrequests") {
       return c.redirect(`/${owner}/${repo}/pulls?q=${encodeURIComponent(q)}`);
+    } else if (type === "discussions") {
+      return c.redirect(`/${owner}/${repo}/discussions?discussions_q=${encodeURIComponent(q)}`);
     }
 
     // Redirect unhandled search types (like code, which requires sign in anyway).
diff --git a/src/scraper.test.ts b/src/scraper.test.ts
index 8dcb0b8..37415b9 100644
--- a/src/scraper.test.ts
+++ b/src/scraper.test.ts
@@ -3,6 +3,8 @@ import { describe, it } from "node:test";
 import {
   getGitHubBlob,
   getGitHubCommits,
+  getGitHubDiscussion,
+  getGitHubDiscussions,
   getGitHubIssues,
   getGitHubSidebar,
   getGitHubLatestCommit,
@@ -498,6 +500,135 @@ describe("GitHub scraper", () => {
     });
   });
 
+  describe("discussions", () => {
+    it("should fetch the discussion list with its categories", async () => {
+      const data = await getGitHubDiscussions("jj-vcs", "jj");
+
+      assert.strictEqual(data.repo.owner, "jj-vcs");
+      assert.strictEqual(data.repo.name, "jj");
+      assert.strictEqual(data.q, undefined);
+      assert.strictEqual(data.category, null);
+
+      assert.ok(data.discussions.length > 0);
+      assert.ok(data.discussions.every((discussion) => discussion.number > 0));
+      assert.ok(data.discussions.every((discussion) => discussion.titleHtml !== ""));
+      assert.ok(data.discussions.every((discussion) => discussion.createdAt));
+
+      assert.deepStrictEqual(
+        data.categories.find((category) => category.slug === "q-a"),
+        { slug: "q-a", name: "Q&A", emoji: "\u{1F64F}" },
+      );
+    });
+
+    // The category link in a row carries the filter it would apply as a query,
+    // which is not part of the slug we route on.
+    it("should narrow the list to one category", async () => {
+      const data = await getGitHubDiscussions("jj-vcs", "jj", { category: "q-a" });
+
+      assert.deepStrictEqual(data.category, { slug: "q-a", name: "Q&A", emoji: "\u{1F64F}" });
+      assert.ok(data.discussions.length > 0);
+      assert.ok(data.discussions.every((discussion) => discussion.category?.slug === "q-a"));
+    });
+
+    it("should search the list with q", async () => {
+      const data = await getGitHubDiscussions("jj-vcs", "jj", { q: "advance-branches" });
+
+      assert.strictEqual(data.q, "advance-branches");
+      const feedback = data.discussions.find((discussion) => discussion.number === 3549);
+      assert.ok(feedback);
+      assert.strictEqual(feedback.author, "emesterhazy");
+      assert.strictEqual(feedback.category?.slug, "general");
+      assert.strictEqual(feedback.createdAt, "2024-04-20T14:32:15Z");
+      assert.strictEqual(feedback.answered, false);
+    });
+
+    it("should fetch a discussion with its comments and replies", async () => {
+      const data = await getGitHubDiscussion("jj-vcs", "jj", 3549);
+
+      assert.strictEqual(data.repo.owner, "jj-vcs");
+      assert.strictEqual(data.number, 3549);
+      // Titles are Markdown, so the code span survives into the HTML.
+      assert.strictEqual(
+        data.titleHtml,
+        "Feedback for the experimental <code>advance-branches</code> feature",
+      );
+      assert.strictEqual(data.author, "emesterhazy");
+      assert.deepStrictEqual(data.category, { slug: "general", name: "General", emoji: null });
+      assert.strictEqual(data.answerAnchor, null);
+
+      assert.strictEqual(data.body.anchor, "discussion-6532740");
+      assert.strictEqual(data.body.author, "emesterhazy");
+      assert.strictEqual(data.body.createdAt, "2024-04-20T14:32:15Z");
+      assert.match(data.body.bodyHtml, /Please leave any feedback/);
+
+      assert.ok(data.comments.length > 0);
+      assert.ok(data.comments.every((comment) => comment.anchor.startsWith("discussioncomment-")));
+      // Replies hang off the comment they answer.
+      const threaded = data.comments.filter((comment) => comment.replies.length > 0);
+      assert.ok(threaded.length > 0);
+      // GitHub collapses the older replies of the longest threads.
+      assert.ok(data.comments.some((comment) => comment.hiddenReplies > 0));
+    });
+
+    it("should mark the comment a discussion was answered by", async () => {
+      const data = await getGitHubDiscussion("mozilla", "pdf.js", 18821);
+
+      assert.strictEqual(data.repo.owner, "mozilla");
+      assert.strictEqual(data.repo.name, "pdf.js");
+      assert.strictEqual(data.number, 18821);
+      assert.strictEqual(
+        data.titleHtml,
+        "[Bug]: TypeError Promise.withResolvers is not a function",
+      );
+      assert.strictEqual(data.author, "techpranav");
+      assert.deepStrictEqual(data.category, { slug: "q-a", name: "Q&A", emoji: null });
+
+      assert.strictEqual(data.body.anchor, "discussion-7249716");
+      assert.strictEqual(data.body.createdAt, "2024-09-29T08:35:02Z");
+      assert.strictEqual(data.body.isAnswer, false);
+
+      assert.strictEqual(data.answerAnchor, "discussioncomment-10945480");
+
+      const answer = data.comments.find((comment) => comment.isAnswer);
+      assert.ok(answer);
+      assert.strictEqual(answer.anchor, data.answerAnchor);
+      assert.strictEqual(answer.author, "Snuffleupagus");
+      assert.deepStrictEqual(answer.labels, ["Collaborator"]);
+      assert.strictEqual(answer.replies.length, 1);
+      assert.strictEqual(answer.replies[0].isAnswer, false);
+    });
+
+    // A comment GitHub collapsed is served as its reason alone: signed out,
+    // there is no author, no timestamp, and no body to show.
+    it("should keep the reason a comment was hidden", async () => {
+      const data = await getGitHubDiscussion("mozilla", "pdf.js", 18821);
+
+      const replies = data.comments.flatMap((comment) => comment.replies);
+      const hidden = replies.find((reply) => reply.anchor === "discussioncomment-10945516");
+      assert.ok(hidden);
+      assert.strictEqual(hidden.hiddenReason, "This comment has been hidden.");
+      assert.strictEqual(hidden.author, null);
+      assert.strictEqual(hidden.createdAt, null);
+      assert.strictEqual(hidden.bodyHtml, "");
+
+      // The comment it is a reply to is shown as usual, hidden reply and all.
+      const parent = data.comments.find((comment) =>
+        comment.replies.some((reply) => reply === hidden),
+      );
+      assert.ok(parent);
+      assert.strictEqual(parent.hiddenReason, null);
+      assert.ok(parent.bodyHtml !== "");
+    });
+
+    it("should throw for a repository with discussions turned off", async () => {
+      await assert.rejects(getGitHubDiscussions("torvalds", "linux"), (err) => {
+        assert(err instanceof GitHubHTTPError, "error should be an HTTPError");
+        assert.strictEqual(err.status, 404);
+        return true;
+      });
+    });
+  });
+
   describe("owner pages", () => {
     it("should fetch user profile", async () => {
       const data = await getGitHubOwner("torvalds");
diff --git a/src/scraper.ts b/src/scraper.ts
index fb48700..d1a1763 100644
--- a/src/scraper.ts
+++ b/src/scraper.ts
@@ -284,6 +284,60 @@ export interface GitHubPulls extends GitHubCommon {
   q?: string;
 }
 
+interface DiscussionCategory {
+  slug: string;
+  name: string;
+  // Every category has an emoji, but GitHub only prints it in some places.
+  emoji: string | null;
+}
+
+interface DiscussionSummary {
+  number: number;
+  // Titles are Markdown, so they can carry code spans and emoji.
+  titleHtml: string;
+  author: string | null;
+  createdAt: string | null;
+  category: DiscussionCategory | null;
+  answered: boolean;
+}
+
+export interface DiscussionComment {
+  // What GitHub's permalinks point at, e.g. "discussioncomment-9174663".
+  anchor: string;
+  author: string | null;
+  createdAt: string | null;
+  // The badges beside the author: Author, Maintainer, Collaborator, ...
+  labels: string[];
+  bodyHtml: string;
+  // How GitHub words a comment it keeps collapsed, e.g. "This comment has been
+  // hidden." or "This comment was marked as off-topic."; null when the comment
+  // is shown as usual. A collapsed comment arrives with no author or body.
+  hiddenReason: string | null;
+  isAnswer: boolean;
+  replies: DiscussionComment[];
+  // Replies GitHub keeps collapsed behind a "show more" button of its own.
+  hiddenReplies: number;
+}
+
+export interface GitHubDiscussions extends GitHubCommon {
+  discussions: DiscussionSummary[];
+  categories: DiscussionCategory[];
+  // The category the list is narrowed to, if any.
+  category: DiscussionCategory | null;
+  q?: string;
+}
+
+export interface GitHubDiscussion extends GitHubCommon {
+  number: number;
+  titleHtml: string;
+  author: string | null;
+  category: DiscussionCategory | null;
+  // The comment a Q&A discussion is answered by, as an anchor on this page.
+  answerAnchor: string | null;
+  body: DiscussionComment;
+  comments: DiscussionComment[];
+}
+
 export interface GitHubCommits extends GitHubNav {
   commitGroups: CommitGroup[];
 }
@@ -664,6 +718,184 @@ export async function getGitHubPulls(
   return { repo: { owner, name: repo }, pulls, q };
 }
 
+// A category link names the category on its own in a discussion's header and
+// in a list row; in the sidebar it wraps an emoji and a label of its own.
+function parseDiscussionCategory(link: Element | null): DiscussionCategory | null {
+  const href = link ? getAttributeValue(link, "href") : undefined;
+  // A list row's category link carries the filter it would apply as a query.
+  const slug = href?.split("?")[0].split("/").pop();
+  if (!link || !slug) return null;
+
+  const label = cssSelect.selectOne(".ActionList-item-label", link) ?? link;
+  const emoji = cssSelect.selectOne("g-emoji", link);
+  return {
+    slug,
+    name: textContent(label).replace(/\s+/g, " ").trim(),
+    emoji: emoji ? textContent(emoji).trim() : null,
+  };
+}
+
+function parseDiscussionCategories(document: AnyNode): DiscussionCategory[] {
+  const categories: DiscussionCategory[] = [];
+  const links = cssSelect.selectAll(
+    'nav[aria-label="Categories"] a[href*="/discussions/categories/"]',
+    document,
+  ) as unknown as Element[];
+  for (const link of links) {
+    const category = parseDiscussionCategory(link);
+    if (category) categories.push(category);
+  }
+  return categories;
+}
+
+function parseDiscussionSummary(row: Element): DiscussionSummary | null {
+  const link = cssSelect.selectOne('a[data-hovercard-type="discussion"]', row);
+  const href = link ? getAttributeValue(link, "href") : undefined;
+  const number = parseInt(href?.split("/").pop() ?? "", 10);
+  if (!link || !number) return null;
+
+  const time = cssSelect.selectOne("relative-time", row);
+
+  return {
+    number,
+    titleHtml: getInnerHTML(link).trim(),
+    author: selectText('a[aria-label$="(author)"]', row),
+    createdAt: time ? (getAttributeValue(time, "datetime") ?? null) : null,
+    category: parseDiscussionCategory(cssSelect.selectOne('a[aria-label$="(category)"]', row)),
+    // An answered thread is called out in green beside its category.
+    answered: cssSelect.selectOne(".color-fg-success", row) !== null,
+  };
+}
+
+export async function getGitHubDiscussions(
+  owner: string,
+  repo: string,
+  { q, category }: { q?: string; category?: string } = {},
+): Promise<GitHubDiscussions> {
+  const base = category
+    ? `${owner}/${repo}/discussions/categories/${category}`
+    : `${owner}/${repo}/discussions`;
+  const suffix = q ? `?discussions_q=${encodeURIComponent(q)}` : "";
+  const html = await fetchGitHubPage(`${base}${suffix}`);
+  const document = parseDocument(html);
+
+  const discussions: DiscussionSummary[] = [];
+  for (const row of cssSelect.selectAll(
+    "li.js-navigation-item",
+    document,
+  ) as unknown as Element[]) {
+    const summary = parseDiscussionSummary(row);
+    if (summary) discussions.push(summary);
+  }
+
+  const categories = parseDiscussionCategories(document);
+
+  return {
+    repo: { owner, name: repo },
+    discussions,
+    categories,
+    category: categories.find((c) => c.slug === category) ?? null,
+    q,
+  };
+}
+
+// A comment and a reply to it are the same markup, with the replies nested
+// inside the comment they answer.
+function parseDiscussionComment(item: Element): DiscussionComment {
+  const target = cssSelect.selectOne(".discussions-timeline-scroll-target[id]", item);
+  const header = cssSelect.selectOne(".timeline-comment-header-text", item);
+  const time = header ? cssSelect.selectOne("relative-time", header) : null;
+  const body = cssSelect.selectOne(".js-comment-body", item);
+
+  // A comment GitHub collapsed has its reason where the header would be, and
+  // nothing else: no author, no time, no body. The header of a comment shown
+  // as usual comes first, so only a collapsed one owns the first match here;
+  // in the others it belongs to a nested reply.
+  const minimized = cssSelect.selectOne(".minimized-comment .timeline-comment-header-text", item);
+  const hiddenReason =
+    header !== null && header === minimized
+      ? textContent(header).replace(/\s+/g, " ").trim()
+      : null;
+
+  const labels: string[] = [];
+  if (header) {
+    for (const label of cssSelect.selectAll(".Label", header) as unknown as Element[]) {
+      labels.push(textContent(label).replace(/\s+/g, " ").trim());
+    }
+  }
+
+  const replies: DiscussionComment[] = [];
+  for (const reply of cssSelect.selectAll(
+    ".discussion-nested-comment-timeline-item",
+    item,
+  ) as unknown as Element[]) {
+    replies.push(parseDiscussionComment(reply));
+  }
+
+  // Long threads arrive with the older replies behind a "Show 5 previous
+  // replies" button, which needs GitHub's JavaScript to load them.
+  let hiddenReplies = 0;
+  for (const button of cssSelect.selectAll(
+    ".discussion-nested-comment-paging-form .Button-label",
+    item,
+  ) as unknown as Element[]) {
+    const count = /(\d+)/.exec(textContent(button));
+    if (count) hiddenReplies += parseInt(count[1], 10);
+  }
+
+  return {
+    anchor: target ? (getAttributeValue(target, "id") ?? "") : "",
+    author: header ? selectText('a[data-hovercard-type="user"]', header) : null,
+    createdAt: time ? (getAttributeValue(time, "datetime") ?? null) : null,
+    labels,
+    bodyHtml: hiddenReason ? "" : body ? getInnerHTML(body).trim() : "",
+    hiddenReason,
+    isAnswer: cssSelect.selectOne(".discussion-footer-answered-badge", item) !== null,
+    replies,
+    hiddenReplies,
+  };
+}
+
+export async function getGitHubDiscussion(
+  owner: string,
+  repo: string,
+  number: number,
+): Promise<GitHubDiscussion> {
+  const html = await fetchGitHubPage(`${owner}/${repo}/discussions/${number}`);
+  const document = parseDocument(html);
+
+  const header = cssSelect.selectOne("#partial-discussion-header", document) as Element | null;
+  if (!header) {
+    throw new Error("Could not find the discussion header");
+  }
+
+  // The discussion's own post opens the timeline; the rest are its comments.
+  const items = cssSelect.selectAll(".discussion-timeline-item", document) as unknown as Element[];
+  if (items.length === 0) {
+    throw new Error("Could not find the discussion body");
+  }
+  const [body, ...comments] = items.map(parseDiscussionComment);
+
+  const title = cssSelect.selectOne(".js-issue-title", header);
+  // Who opened the discussion, and where, sits under the title; an answer, when
+  // there is one, is in a state badge above it.
+  const meta = cssSelect.selectOne("div.color-fg-muted", header) as Element | null;
+  const answer = cssSelect.selectOne(".js-discussions-goto-answer-button", header);
+
+  return {
+    repo: { owner, name: repo },
+    number,
+    titleHtml: title ? getInnerHTML(title).trim() : "",
+    author: meta ? selectText("a[href]", meta) : null,
+    category: parseDiscussionCategory(
+      meta ? cssSelect.selectOne('a[href*="/discussions/categories/"]', meta) : null,
+    ),
+    answerAnchor: answer ? (getAttributeValue(answer, "href") ?? "").replace(/^#/, "") : null,
+    body,
+    comments,
+  };
+}
+
 export async function getGitHubCommits(
   owner: string,
   repo: string,
-- 
cgit v1.3.1