Ci/discord release announce

.github/workflows/release.yml

@@ -365,6 +365,7 @@ jobs:
           cat NOTES.md
 
       - name: Publish
+        id: publish
         env:
           GH_TOKEN: ${{ github.token }}
         run: |
@@ -386,3 +387,38 @@ jobs:
             --notes-file NOTES.md \
             --prerelease="${{ needs.version.outputs.prerelease }}" \
             artifacts/*
+          echo "tag=$tag" >> "$GITHUB_OUTPUT"
+
+      # Here rather than in a workflow of its own listening on `release`.
+      # GitHub refuses to start a workflow run from an event its own
+      # GITHUB_TOKEN caused, and the release above is created with exactly that
+      # token — an `on: release: [published]` workflow would sit silent forever
+      # and look like a Discord problem.
+      #
+      # `published` would also have been the only safe type to listen for:
+      # publishing a pre-release fires `published` *and* `prereleased`, so
+      # asking for both announces every snapshot twice.
+      - name: Announce on Discord
+        if: always() && steps.publish.outputs.tag != ''
+        env:
+          DISCORD_WEBHOOK: ${{ secrets.DISCORD_WEBHOOK }}
+          # Not secrets: a custom emoji's id is visible to everyone who can see
+          # the server, and it is useless without the webhook that is. Here
+          # rather than as defaults in the script, so a fork announcing to its
+          # own server falls back to the unicode pair instead of referencing
+          # emoji it does not have.
+          DPIP_EMOJI_ANDROID: "<:android:1539201870935892028>"
+          DPIP_EMOJI_IOS: "<:ios:1539201897766981692>"
+          # Without it the release lookup runs unauthenticated, at 60 requests
+          # an hour shared across everything on this runner's IP.
+          GITHUB_TOKEN: ${{ github.token }}
+        run: |
+          if [ -z "${DISCORD_WEBHOOK:-}" ]; then
+            echo "::notice::DISCORD_WEBHOOK is not set — nothing announced"
+            exit 0
+          fi
+          # A warning, not a failure. The build is published and the artifacts
+          # are downloadable by the time this runs; turning the job red over an
+          # announcement would say the release did not happen.
+          python3 tool/release/discord.py "${{ steps.publish.outputs.tag }}" ||
+            echo "::warning::Discord announcement failed — the release itself is fine"

test/tool/discord_payload_test.dart

@@ -0,0 +1,107 @@
+/// `tool/release/discord.py` — the release announcement, inside Discord's
+/// limits.
+///
+/// The truncation path only runs on a release big enough to overflow, which is
+/// exactly the release nobody wants to discover it on. These force the overflow
+/// with a smaller budget so the behaviour is exercised on every run, and read a
+/// committed fixture rather than the API so they are neither flaky nor
+/// rate-limited.
+library;
+
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+
+const _android = '<:android:1539201870935892028>';
+const _ios = '<:ios:1539201897766981692>';
+
+Map<String, Object?> payload({int? limit, bool short = false}) {
+  final root = Directory.current.path;
+  final result = Process.runSync(
+    'python3',
+    ['$root/tool/release/discord.py', '26w34c', '--dry-run'],
+    environment: {
+      'DPIP_RELEASE_JSON': '$root/test/tool/fixtures/release_26w34c.json',
+      'DPIP_EMOJI_ANDROID': short ? '<:a:1>' : _android,
+      'DPIP_EMOJI_IOS': short ? '<:i:2>' : _ios,
+      if (limit != null) 'DPIP_DISCORD_LIMIT': '$limit',
+    },
+  );
+  expect(result.exitCode, 0, reason: result.stderr.toString());
+  return jsonDecode(result.stdout as String) as Map<String, Object?>;
+}
+
+List<Object?> embeds(Map<String, Object?> p) => p['embeds']! as List<Object?>;
+String description(Map<String, Object?> p) =>
+    (embeds(p).single as Map<String, Object?>)['description']! as String;
+
+/// `… (15/22)` → 15.
+int shown(String text) =>
+    RegExp(r'… \((\d+)/\d+\)')
+        .allMatches(text)
+        .map((m) => int.parse(m.group(1)!))
+        .fold(0, (a, b) => a + b);
+
+void main() {
+  test('one embed, always inside the description limit', () {
+    for (final limit in [4096, 3000, 2000, 1200]) {
+      final p = payload(limit: limit);
+      expect(embeds(p), hasLength(1), reason: 'limit $limit');
+      expect(
+        description(p).length,
+        lessThanOrEqualTo(limit),
+        reason: 'limit $limit',
+      );
+    }
+  });
+
+  test('the whole note when it fits, nothing marked missing', () {
+    // Short ids stand in for a guild whose emoji names are brief; the note then
+    // fits and no category should claim to be cut. Shortening only one of the
+    // two still overflows — 55 entries pay for both on almost every line.
+    final text = description(payload(short: true));
+
+    expect(text, isNot(contains('… (')));
+    expect(text, contains('修正換行的更新日誌條目在發布時被從中間截斷'));
+  });
+
+  test('hashes are dropped before any entry is', () {
+    // The order matters: a hash costs a click on the link at the bottom, a
+    // dropped entry means a change shipped and nobody was told.
+    final full = description(payload(short: true));
+    final tight = description(payload());
+
+    expect(full, contains('`c5fdbd31`'));
+    expect(tight, isNot(contains('`c5fdbd31`')));
+  });
+
+  test('a cut is split evenly between the categories', () {
+    // Filling from the top until the budget runs out would spend it all on
+    // 新功能 and post 錯誤修正 as an empty heading — a release where the fixes
+    // are the point would read as a release with no fixes.
+    final text = description(payload(limit: 1500));
+    final counts = RegExp(r'… \((\d+)/(\d+)\)')
+        .allMatches(text)
+        .map((m) => int.parse(m.group(1)!))
+        .toList();
+
+    expect(counts, hasLength(greaterThanOrEqualTo(2)));
+    expect(counts.toSet(), hasLength(1), reason: 'categories got $counts');
+  });
+
+  test('a smaller budget never shows more', () {
+    expect(
+      shown(description(payload(limit: 1200))),
+      lessThanOrEqualTo(shown(description(payload(limit: 2000)))),
+    );
+  });
+
+  test('the heading, the subtext and the link all survive a cut', () {
+    final text = description(payload(limit: 1200));
+
+    expect(text, startsWith('# 26w34c'));
+    expect(text, contains('-# 快照，取自 main 的'));
+    expect(text, contains('releases/tag/26w34c'));
+  });
+}