chore: lint and remove unused variables

src/invidious/routes/api/manifest.cr

@@ -81,7 +81,6 @@ module Invidious::Routes::API::Manifest
               xml.element("AdaptationSet", id: i, mimeType: mime_type, startWithSAP: 1, subsegmentAlignment: true, label: "#{displayname} [#{bitrate}k]", lang: lang) do
                 codecs = fmt["mimeType"].as_s.split("codecs=")[1].strip('"')
                 bandwidth = fmt["bitrate"].as_i
-                itag = fmt["itag"].as_i
                 url = fmt["url"].as_s
 
                 xml.element("Role", schemeIdUri: "urn:mpeg:dash:role:2011", value: is_default ? "main" : "alternate")

src/invidious/routes/api/v1/authenticated.cr

@@ -380,7 +380,6 @@ module Invidious::Routes::API::V1::Authenticated
   def self.get_tokens(env)
     env.response.content_type = "application/json"
     user = env.get("user").as(User)
-    scopes = env.get("scopes").as(Array(String))
 
     tokens = Invidious::Database::SessionIDs.select_all(user.email)
 
@@ -398,6 +397,8 @@ module Invidious::Routes::API::V1::Authenticated
 
   def self.register_token(env)
     user = env.get("user").as(User)
+    # Used by template bellow.
+    # ameba:disable Lint/UselessAssign
     locale = env.get("preferences").as(Preferences).locale
 
     case env.request.headers["Content-Type"]?
@@ -424,6 +425,8 @@ module Invidious::Routes::API::V1::Authenticated
     if sid = env.get?("sid").try &.as(String)
       env.response.content_type = "text/html"
 
+      # Used by template bellow.
+      # ameba:disable Lint/UselessAssign
       csrf_token = generate_response(sid, {":authorize_token"}, HMAC_KEY, use_nonce: true)
       return templated "user/authorize_token"
     else
@@ -462,7 +465,6 @@ module Invidious::Routes::API::V1::Authenticated
   def self.unregister_token(env)
     env.response.content_type = "application/json"
 
-    user = env.get("user").as(User)
     scopes = env.get("scopes").as(Array(String))
 
     session = env.params.json["session"]?.try &.as(String)
@@ -484,7 +486,7 @@ module Invidious::Routes::API::V1::Authenticated
     env.response.content_type = "text/event-stream"
 
     raw_topics = env.params.body["topics"]? || env.params.query["topics"]?
-    topics = raw_topics.try &.split(",").uniq.first(1000)
+    topics = raw_topics.try &.split(",").uniq!.first(1000)
     topics ||= [] of String
 
     Helpers.create_notification_stream(env, topics, CONNECTION_CHANNEL)

src/invidious/routes/api/v1/channels.cr

@@ -35,7 +35,6 @@ module Invidious::Routes::API::V1::Channels
         # playlist doesnt exist.
         videos = [] of PlaylistVideo
       end
-      next_continuation = nil
     else
       begin
         videos, _ = Channel::Tabs.get_videos(channel, sort_by: sort_by)

src/invidious/routes/api/v1/feeds.cr

@@ -8,7 +8,7 @@ module Invidious::Routes::API::V1::Feeds
     trending_type = env.params.query["type"]?
 
     begin
-      trending, plid = fetch_trending(trending_type, region, locale)
+      trending, _ = fetch_trending(trending_type, region, locale)
     rescue ex
       return error_json(500, ex)
     end

src/invidious/routes/api/v1/videos.cr

@@ -340,6 +340,9 @@ module Invidious::Routes::API::V1::Videos
     format ||= "json"
 
     action = env.params.query["action"]?
+    # 2026-09-14 TODO: Check if action is or can be used somewhere
+    # as is unused currently, but for some reason is it here.
+    # ameba:disable Lint/UselessAssign
     action ||= "action_get_comments"
 
     continuation = env.params.query["continuation"]?

src/invidious/yt_backend/youtube_api.cr

@@ -696,7 +696,7 @@ module YoutubeAPI
       # Multiple encodings can be combined, and are listed in the order
       # in which they were applied. E.g: "deflate, gzip" means that the
       # content must be first "gunzipped", then "defated".
-      encodings.split(',').reverse.each do |enc|
+      encodings.split(',').reverse!.each do |enc|
         case enc.strip(' ')
         when "gzip"
           body_io = Compress::Gzip::Reader.new(body_io, sync_close: true)