Troubleshooting Code: (KeyError) key :changeset not found

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I am following this tutorial . I have followed carefully correcting errors as I go. The app allows you to create a blog post and add comments if you so choose. When I click show Posts, this error I am getting:

[error] #PID<0.581.0> running BlogAppWeb.Endpoint (connection #PID<0.552.0>, stream id 6) terminated
Server: localhost:4000 (http)
Request: GET /posts/1
** (exit) an exception was raised:
    ** (KeyError) key :changeset not found in: %{conn: %Plug.Conn{adapter: {Plug.Cowboy.Conn, :...}, assigns: %{layout: {BlogAppWeb.LayoutView, "app.html"}, post: %BlogApp.Posts.Post{__meta__: #Ecto.Schema.Metadata<:loaded, "posts">, body: "This here is my duck named Mr.Lump My friend Anum is here.", comments: #Ecto.Association.NotLoaded<association :comments is not loaded>, id: 1, inserted_at: ~N[2022-03-17 17:38:18], title: "Look at my Duck, his name is Lump", updated_at: ~N[2022-03-18 17:45:40]}}, body_params: %{}, cookies: %{"_blog_app_key" => "SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYSjBybkJSX2U0ZHVyalNoLVkzeHhCdlRt.wbQhUfCTv_8d1yKDupYSNN_ewiSgDMVBypamZHRIP1o", "_live_view_todos_key" => "SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYWWJ1XzE5MnJSSkV6OVl3eVl0cUpvM2pN.NJYDbH-n7JlaQFMHL2_x-T2zhhvyYD6XBmo8GequxP8"}, halted: false, host: "localhost", method: "GET", owner: #PID<0.581.0>, params: %{"id" => "1"}, path_info: ["posts", "1"], path_params: %{"id" => "1"}, port: 4000, private: %{BlogAppWeb.Router => {[], %{Plug.Swoosh.MailboxPreview => ["mailbox"]}}, :before_send => [#Function<0.16477574/1 in Plug.CSRFProtection.call/2>, #Function<2.17183421/1 in Phoenix.Controller.fetch_flash/2>, #Function<0.77458138/1 in Plug.Session.before_send/2>, #Function<0.23023616/1 in Plug.Telemetry.call/2>, #Function<1.46227650/1 in Phoenix.LiveReloader.before_send_inject_reloader/3>], :phoenix_action => :show, :phoenix_controller => BlogAppWeb.PostController, :phoenix_endpoint => BlogAppWeb.Endpoint, :phoenix_flash => %{}, :phoenix_format => "html", :phoenix_layout => {BlogAppWeb.LayoutView, :app}, :phoenix_request_logger => {"request_logger", "request_logger"}, :phoenix_root_layout => {BlogAppWeb.LayoutView, :root}, :phoenix_router => BlogAppWeb.Router, :phoenix_template => "show.html", :phoenix_view => BlogAppWeb.PostView, :plug_session => %{"_csrf_token" => "J0rnBR_e4durjSh-Y3xxBvTm"}, :plug_session_fetch => :done}, query_params: %{}, query_string: "", remote_ip: {127, 0, 0, 1}, req_cookies: %{"_blog_app_key" => "SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYSjBybkJSX2U0ZHVyalNoLVkzeHhCdlRt.wbQhUfCTv_8d1yKDupYSNN_ewiSgDMVBypamZHRIP1o", "_live_view_todos_key" => "SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYWWJ1XzE5MnJSSkV6OVl3eVl0cUpvM2pN.NJYDbH-n7JlaQFMHL2_x-T2zhhvyYD6XBmo8GequxP8"}, req_headers: [{"accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9"}, {"accept-encoding", "gzip, deflate, br"}, {"accept-language", "en-US,en;q=0.9"}, {"connection", "keep-alive"}, {"cookie", "_live_view_todos_key=SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYWWJ1XzE5MnJSSkV6OVl3eVl0cUpvM2pN.NJYDbH-n7JlaQFMHL2_x-T2zhhvyYD6XBmo8GequxP8; _blog_app_key=SFMyNTY.g3QAAAABbQAAAAtfY3NyZl90b2tlbm0AAAAYSjBybkJSX2U0ZHVyalNoLVkzeHhCdlRt.wbQhUfCTv_8d1yKDupYSNN_ewiSgDMVBypamZHRIP1o"}, {"host", "localhost:4000"}, {"referer", "http://localhost:4000/posts"}, {"sec-ch-ua", "\" Not A;Brand\";v=\"99\", \"Chromium\";v=\"98\", \"Google Chrome\";v=\"98\""}, {"sec-ch-ua-mobile", "?0"}, {"sec-ch-ua-platform", "\"macOS\""}, {"sec-fetch-dest", "document"}, {"sec-fetch-mode", "navigate"}, {"sec-fetch-site", "same-origin"}, {"sec-fetch-user", "?1"}, {"upgrade-insecure-requests", "1"}, {"user-agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36"}], request_path: "/posts/1", resp_body: nil, resp_cookies: %{}, resp_headers: [{"cache-control", "max-age=0, private, must-revalidate"}, {"x-request-id", "Ft5qQ01M_yh3344AAAAE"}, {"x-frame-options", "SAMEORIGIN"}, {"x-xss-protection", "1; mode=block"}, {"x-content-type-options", "nosniff"}, {"x-download-options", "noopen"}, {"x-permitted-cross-domain-policies", "none"}, {"cross-origin-window-policy", "deny"}], scheme: :http, script_name: [], secret_key_base: :..., state: :unset, status: nil}, post: %BlogApp.Posts.Post{__meta__: #Ecto.Schema.Metadata<:loaded, "posts">, body: "This here is my duck named Mr.Lump My friend Anum is here.", comments: #Ecto.Association.NotLoaded<association :comments is not loaded>, id: 1, inserted_at: ~N[2022-03-17 17:38:18], title: "Look at my Duck, his name is Lump", updated_at: ~N[2022-03-18 17:45:40]}}
        (blog_app 0.1.0) lib/blog_app_web/templates/post/show.html.heex:19: anonymous fn/2 in BlogAppWeb.PostView."show.html"/1
        (phoenix_live_view 0.17.7) lib/phoenix_live_view/engine.ex:124: Phoenix.HTML.Safe.Phoenix.LiveView.Rendered.to_iodata/1
        (phoenix_live_view 0.17.7) lib/phoenix_live_view/engine.ex:140: Phoenix.HTML.Safe.Phoenix.LiveView.Rendered.to_iodata/3
        (phoenix 1.6.6) lib/phoenix/controller.ex:772: Phoenix.Controller.render_and_send/4
        (blog_app 0.1.0) lib/blog_app_web/controllers/post_controller.ex:1: BlogAppWeb.PostController.action/2
        (blog_app 0.1.0) lib/blog_app_web/controllers/post_controller.ex:1: BlogAppWeb.PostController.phoenix_controller_pipeline/2
        (phoenix 1.6.6) lib/phoenix/router.ex:355: Phoenix.Router.__call__/2
        (blog_app 0.1.0) lib/blog_app_web/endpoint.ex:1: BlogAppWeb.Endpoint.plug_builder_call/2
        (blog_app 0.1.0) lib/plug/debugger.ex:136: BlogAppWeb.Endpoint."call (overridable 3)"/2
        (blog_app 0.1.0) lib/blog_app_web/endpoint.ex:1: BlogAppWeb.Endpoint.call/2
        (phoenix 1.6.6) lib/phoenix/endpoint/cowboy2_handler.ex:54: Phoenix.Endpoint.Cowboy2Handler.init/4
        (cowboy 2.9.0) /Users/shansiddiqui/Desktop/blog_app/deps/cowboy/src/cowboy_handler.erl:37: :cowboy_handler.execute/2
        (cowboy 2.9.0) /Users/shansiddiqui/Desktop/blog_app/deps/cowboy/src/cowboy_stream_h.erl:306: :cowboy_stream_h.execute/3
        (cowboy 2.9.0) /Users/shansiddiqui/Desktop/blog_app/deps/cowboy/src/cowboy_stream_h.erl:295: :cowboy_stream_h.request_process/3
        (stdlib 3.17) proc_lib.erl:226: :proc_lib.init_p_do_apply/3

This error is coming when I Get Posts, also I cant show posts? Any Idea to go around this

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Since that’s an exercise I believe there’s no harm if you post it publicly on GitHub and link it here. Maybe the tutorial is stale, maybe it made a small error (or maybe you did).

In any case yeah, there’s no Ecto.Changeset in the object that’s being consulted nor there should be so there’s code that’s looking at the wrong place.

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4

I actually did find the answer I combed the code and found that there were two functions. I am running into a new error that is confusing me!

Now I have a new error compile error. The function does exist but, cannot be found.Do you think it was to do with the alias (referencing) the component?

Error:

== Compilation error in file lib/blog_app_web/views/post_view.ex ==
** (CompileError) lib/blog_app_web/views/post_view.ex:2: module BlogWeb is not loaded and could not be found
    (elixir 1.13.3) expanding macro: Kernel.use/2
    lib/blog_app_web/views/post_view.ex:2: BlogWeb.PostView (module)

Post_view.ex:

defmodule BlogWeb.PostView do
	use BlogWeb, :view
	alias BlogApp.Posts

	def get_comments_count(post_id) do
		Posts.get_number_of_comments(post_id)
	end
end
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5

Look for which module in your app defines a view function e.g.

defmodule YourModule do
  dev view do
    # ...
  end
end

In your case it should be BlogWeb but who knows, maybe it’s another one.

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