Allow the indexed pack icon in packwiz channel publication

scripts/publish_pack.py

@@ -115,12 +115,21 @@ def remote_tag_commit(tag):
     return found.get('refs/tags/' + tag + '^{}') or found.get('refs/tags/' + tag)
 
 
+def channel_file(relative):
+    """The indexed pack icon is the only non-TOML file allowed on the channel."""
+    path = Path(relative)
+    return path.suffix == '.toml' or path.as_posix() == 'icon.png'
+
+
 def publish_channel(origin, version, source_head):
     staged = ROOT / 'build/packwiz-release'
     pack.check_index(staged)
     files = [path for path in staged.rglob('*') if path.is_file()]
-    pack.require(all(path.suffix == '.toml' for path in files),
-                 'Distribution branch must contain only generated TOML metadata')
+    pack.require(all(channel_file(path.relative_to(staged)) for path in files),
+                 'Distribution branch must contain only generated TOML metadata and the pack icon')
+    if (staged / 'icon.png').exists():
+        pack.require((staged / 'icon.png').read_bytes() == (ROOT / 'packwiz/icon.png').read_bytes(),
+                     'Distribution icon differs from the verified source icon')
     remote = git('ls-remote', '--heads', 'origin', 'refs/heads/' + CHANNEL)
     with tempfile.TemporaryDirectory(prefix='sanctuary-pack-channel-') as temp:
         directory = Path(temp)
@@ -134,7 +143,7 @@ def publish_channel(origin, version, source_head):
             git('fetch', '--quiet', 'origin', CHANNEL, cwd=directory)
             git('checkout', '--quiet', '-b', CHANNEL, 'FETCH_HEAD', cwd=directory)
             tracked = git('ls-files', cwd=directory).splitlines()
-            pack.require(all(name.endswith('.toml') for name in tracked),
+            pack.require(all(channel_file(name) for name in tracked),
                          'Existing distribution branch contains unexpected files')
             for name in tracked:
                 (directory / name).unlink()