From c81452f2a4ee165442b6785c9b3a18d35d4a7386 Mon Sep 17 00:00:00 2001
From: EazyHood <209367218+EazyHood@users.noreply.github.com>
Date: Sun, 2 Aug 2026 13:10:56 -0500
Subject: [PATCH] channels: handle incomplete auto-generated payloads

---
 spec/invidious/channels/about_spec.cr        | 29 +++++++++++++++++---
 spec/invidious/yt_backend/extractors_spec.cr | 22 +++++++++++++++
 src/invidious/channels/about.cr              | 10 +++++--
 src/invidious/yt_backend/extractors.cr       |  3 +-
 4 files changed, 57 insertions(+), 7 deletions(-)
 create mode 100644 spec/invidious/yt_backend/extractors_spec.cr

diff --git a/spec/invidious/channels/about_spec.cr b/spec/invidious/channels/about_spec.cr
index 66f8e029..abf21809 100644
--- a/spec/invidious/channels/about_spec.cr
+++ b/spec/invidious/channels/about_spec.cr
@@ -69,7 +69,7 @@ Spectator.describe "extract_auto_generated_channel_header" do
     expect(header[:author_thumbnail]).to eq("//yt3.example/first")
   end
 
-  it "falls back to the ucid when the carousel carries no topic details" do
+  it "raises when the carousel carries no topic details" do
     initdata = JSON.parse(<<-JSON).as_h
       {
         "header": {
@@ -82,10 +82,31 @@ Spectator.describe "extract_auto_generated_channel_header" do
       }
       JSON
 
-    header = extract_auto_generated_channel_header(initdata, "UCEgdi0XIXXZ-qJOFPf4JSKw")
+    expect do
+      extract_auto_generated_channel_header(initdata, "UCEgdi0XIXXZ-qJOFPf4JSKw")
+    end.to raise_error(InfoException)
+  end
 
-    expect(header[:author]).to eq("UCEgdi0XIXXZ-qJOFPf4JSKw")
-    expect(header[:author_thumbnail]).to eq("")
+  it "raises when the carousel topic details have no title" do
+    initdata = JSON.parse(<<-JSON).as_h
+      {
+        "header": {
+          "carouselHeaderRenderer": {
+            "contents": [
+              {
+                "topicChannelDetailsRenderer": {
+                  "avatar": {"thumbnails": [{"url": "//yt3.example/avatar"}]}
+                }
+              }
+            ]
+          }
+        }
+      }
+      JSON
+
+    expect do
+      extract_auto_generated_channel_header(initdata, "UCEgdi0XIXXZ-qJOFPf4JSKw")
+    end.to raise_error(InfoException)
   end
 
   it "parses the current pageHeaderRenderer shape" do
diff --git a/spec/invidious/yt_backend/extractors_spec.cr b/spec/invidious/yt_backend/extractors_spec.cr
new file mode 100644
index 00000000..a4c2dc0a
--- /dev/null
+++ b/spec/invidious/yt_backend/extractors_spec.cr
@@ -0,0 +1,22 @@
+require "../../parsers_helper"
+
+Spectator.describe "YouTubeTabs" do
+  it "treats a selected tab without content as empty" do
+    initdata = JSON.parse(<<-JSON).as_h
+      {
+        "contents": {
+          "twoColumnBrowseResultsRenderer": {
+            "tabs": [
+              {"tabRenderer": {"selected": true}}
+            ]
+          }
+        }
+      }
+      JSON
+
+    items, continuation = extract_items(initdata)
+
+    expect(items).to be_empty
+    expect(continuation).to be_nil
+  end
+end
diff --git a/src/invidious/channels/about.cr b/src/invidious/channels/about.cr
index aec8d27d..2e027062 100644
--- a/src/invidious/channels/about.cr
+++ b/src/invidious/channels/about.cr
@@ -75,9 +75,15 @@ def extract_auto_generated_channel_header(initdata : Hash(String, JSON::Any), uc
     # This shape carries neither a banner nor a description.
     details = extract_topic_channel_details(initdata)
 
-    author = details.try &.dig?("title", "simpleText").try &.as_s || ucid
+    unless details
+      raise InfoException.new("Could not extract the carousel header of channel #{ucid}")
+    end
+
+    author = details.dig?("title", "simpleText").try &.as_s
+    author ||= raise InfoException.new("Could not extract the carousel title of channel #{ucid}")
     author_url = "https://www.youtube.com/channel/#{ucid}"
-    author_thumbnail = details.try &.dig?("avatar", "thumbnails", 0, "url").try &.as_s || ""
+    author_thumbnail = details.dig?("avatar", "thumbnails", 0, "url").try &.as_s
+    author_thumbnail ||= raise InfoException.new("Could not extract the carousel thumbnail of channel #{ucid}")
   else
     raise InfoException.new("Could not extract the header of channel #{ucid}")
   end
diff --git a/src/invidious/yt_backend/extractors.cr b/src/invidious/yt_backend/extractors.cr
index b2226e74..72c3e144 100644
--- a/src/invidious/yt_backend/extractors.cr
+++ b/src/invidious/yt_backend/extractors.cr
@@ -964,7 +964,8 @@ private module Extractors
 
     private def self.extract(target)
       raw_items = [] of JSON::Any
-      content = extract_selected_tab(target["tabs"])["content"]
+      content = extract_selected_tab(target["tabs"])["content"]?
+      return raw_items if content.nil?
 
       if section_list_contents = content.dig?("sectionListRenderer", "contents")
         raw_items = unpack_section_list(section_list_contents)