feat(github): pull request tool window, timeline and review flow (#477)

Replaces the Pull Requests tool window with a full review workflow on top of gh's authentication.

- List with search, quick filters and paging; a tab per pull request and a New Pull Request tab.
- Details: commit picker, changes tree with viewed state, CI and reviewer status, merge, close and reopen.
- Timeline editor: comments, review threads, reactions and suggested changes.
- Review in the diff viewer and, for the checked-out branch, in the editor (review mode).
- New generic vcs extension points: registerDiffViewerProvider, lineInlays, reviewGutter, branch widget extensions; new vcs_merge_base and gh_api commands.
- CSP: img-src allows https://avatars.githubusercontent.com for avatars.

Fixed while testing against a real repository: remotes behind an SSH host alias, mergeability stuck on UNKNOWN, Apply Locally staying disabled after a checkout, relative links navigating the app's page, and review inlays wider than the pane.

Co-authored-by: imacross <[email protected]>

src/features/github/data/list.ts

@@ -0,0 +1,159 @@
+/**
+ * The pull request list (IntelliJ's `GHPRListLoader` over `issueSearch`): pages of 50,
+ * cursor-paged, for the current search value. `loadMore()` fetches the next page (the
+ * list calls it while scrolling past 70%); `reloadList()` starts over, keeping the rows
+ * visible until the first page arrives. Rows are refreshed in place when a pull request's
+ * details load (`updateListItem`).
+ */
+import { create } from "zustand";
+import { errorMessage } from "../api/client";
+import * as api from "../api/requests";
+import type { GHPullRequest, GHPullRequestShort } from "../api/types";
+import { listSearchQuery, sameSearch, type PrSearchValue } from "./model";
+import { useGhRepository } from "./repository";
+
+interface ListState {
+  search: PrSearchValue;
+  items: GHPullRequestShort[];
+  cursor: string | null;
+  hasMore: boolean;
+  loading: boolean;
+  error: string | null;
+  /** The first page of the current search arrived (`items` are for `search`). */
+  loaded: boolean;
+}
+
+export const useGhPrList = create<ListState>(() => ({
+  search: {},
+  items: [],
+  cursor: null,
+  hasMore: true,
+  loading: false,
+  error: null,
+  loaded: false,
+}));
+
+let seq = 0;
+
+async function fetchPage(reset: boolean): Promise<void> {
+  const repo = useGhRepository.getState().connection?.coordinates;
+  if (!repo) return;
+  const my = ++seq;
+  const s = useGhPrList.getState();
+  useGhPrList.setState({ loading: true, error: null });
+  try {
+    const page = await api.searchPullRequests(listSearchQuery(repo, s.search), reset ? null : s.cursor);
+    if (my !== seq) return;
+    useGhPrList.setState((cur) => {
+      const items = reset
+        ? page.nodes
+        : [...cur.items, ...page.nodes.filter((n) => !cur.items.some((i) => i.id === n.id))];
+      return {
+        items,
+        cursor: page.pageInfo.endCursor,
+        hasMore: page.pageInfo.hasNextPage,
+        loading: false,
+        loaded: true,
+      };
+    });
+  } catch (e) {
+    if (my !== seq) return;
+    useGhPrList.setState({
+      loading: false,
+      error: errorMessage(e),
+      hasMore: false,
+      loaded: true,
+      ...(reset ? { items: [] } : {}),
+    });
+  }
+}
+
+/** Shows the pull requests matching `search` (from the first page). */
+export function setListSearch(search: PrSearchValue): Promise<void> {
+  const same = sameSearch(useGhPrList.getState().search, search);
+  useGhPrList.setState({ search, ...(same ? {} : { items: [], loaded: false }), cursor: null, hasMore: true });
+  return fetchPage(true);
+}
+
+/** Loads the next page, if there is one and none is loading. */
+export function loadMore(): Promise<void> {
+  const s = useGhPrList.getState();
+  if (s.loading || !s.hasMore || !s.loaded) return Promise.resolve();
+  return fetchPage(false);
+}
+
+/** "Refresh List": the current search from the first page. */
+export function reloadList(): Promise<void> {
+  useGhPrList.setState({ cursor: null, hasMore: true });
+  return fetchPage(true);
+}
+
+/** Replaces the row of `pr` with fresher data (details loaded, a mutation's result). */
+export function updateListItem(pr: GHPullRequestShort | GHPullRequest) {
+  useGhPrList.setState((s) => {
+    const i = s.items.findIndex((x) => x.id === pr.id);
+    if (i < 0) return s;
+    const items = [...s.items];
+    items[i] = { ...items[i]!, ...pickShort(pr) };
+    return { items };
+  });
+}
+
+function pickShort(pr: GHPullRequestShort): GHPullRequestShort {
+  const {
+    id,
+    url,
+    number,
+    title,
+    state,
+    isDraft,
+    author,
+    createdAt,
+    updatedAt,
+    isReadByViewer,
+    assignees,
+    labels,
+    reviewRequests,
+    reviewThreads,
+    reviews,
+    reactions,
+    mergeable,
+    viewerCanUpdate,
+    viewerCanReact,
+    viewerDidAuthor,
+  } = pr;
+  return {
+    id,
+    url,
+    number,
+    title,
+    state,
+    isDraft,
+    author,
+    createdAt,
+    updatedAt,
+    isReadByViewer,
+    assignees,
+    labels,
+    reviewRequests,
+    reviewThreads,
+    reviews,
+    reactions,
+    mergeable,
+    viewerCanUpdate,
+    viewerCanReact,
+    viewerDidAuthor,
+  };
+}
+
+/** Forgets the rows (disconnect, another repository). */
+export function clearList() {
+  seq++;
+  useGhPrList.setState({ items: [], cursor: null, hasMore: true, loading: false, error: null, loaded: false });
+}
+
+useGhRepository.subscribe((s, prev) => {
+  const a = s.connection?.coordinates;
+  const b = prev.connection?.coordinates;
+  if (a?.owner !== b?.owner || a?.name !== b?.name) clearList();
+});