Merge branch 'fix/federation-context-issues' into 'develop'

Fix reply context fixing (Pleroma replies to Misskey threads) and removal of context objects

See merge request pleroma/pleroma!3717

33 files changed, 586 insertions, 121 deletions

diff --git a/config/config.exs b/config/config.exs
index 1653358a0..aa53b7653 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -673,6 +673,8 @@ config :pleroma, :features, improved_hashtag_timeline: :auto
 
 config :pleroma, :populate_hashtags_table, fault_rate_allowance: 0.01
 
+config :pleroma, :delete_context_objects, fault_rate_allowance: 0.01
+
 config :pleroma, :env, Mix.env()
 
 config :http_signatures,
diff --git a/config/description.exs b/config/description.exs
index c6c6b1b5d..c28447b37 100644
--- a/config/description.exs
+++ b/config/description.exs
@@ -497,6 +497,27 @@ config :pleroma, :config_description, [
   },
   %{
     group: :pleroma,
+    key: :delete_context_objects,
+    type: :group,
+    description: "`delete_context_objects` background migration settings",
+    children: [
+      %{
+        key: :fault_rate_allowance,
+        type: :float,
+        description:
+          "Max accepted rate of objects that failed in the migration. Any value from 0.0 which tolerates no errors to 1.0 which will enable the feature even if context object deletion failed for all records.",
+        suggestions: [0.01]
+      },
+      %{
+        key: :sleep_interval_ms,
+        type: :integer,
+        description:
+          "Sleep interval between each chunk of processed records in order to decrease the load on the system (defaults to 0 and should be keep default on most instances)."
+      }
+    ]
+  },
+  %{
+    group: :pleroma,
     key: :instance,
     type: :group,
     description: "Instance-related settings",
diff --git a/lib/pleroma/application.ex b/lib/pleroma/application.ex
index b977afea1..bf5c57840 100644
--- a/lib/pleroma/application.ex
+++ b/lib/pleroma/application.ex
@@ -249,7 +249,8 @@ defmodule Pleroma.Application do
 
   defp background_migrators do
     [
-      Pleroma.Migrators.HashtagsTableMigrator
+      Pleroma.Migrators.HashtagsTableMigrator,
+      Pleroma.Migrators.ContextObjectsDeletionMigrator
     ]
   end
 
diff --git a/lib/pleroma/data_migration.ex b/lib/pleroma/data_migration.ex
index 59d891d8d..8451678fc 100644
--- a/lib/pleroma/data_migration.ex
+++ b/lib/pleroma/data_migration.ex
@@ -42,4 +42,5 @@ defmodule Pleroma.DataMigration do
   end
 
   def populate_hashtags_table, do: get_by_name("populate_hashtags_table")
+  def delete_context_objects, do: get_by_name("delete_context_objects")
 end
diff --git a/lib/pleroma/migrators/context_objects_deletion_migrator.ex b/lib/pleroma/migrators/context_objects_deletion_migrator.ex
new file mode 100644
index 000000000..fb224795a
--- /dev/null
+++ b/lib/pleroma/migrators/context_objects_deletion_migrator.ex
@@ -0,0 +1,139 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Migrators.ContextObjectsDeletionMigrator do
+  defmodule State do
+    use Pleroma.Migrators.Support.BaseMigratorState
+
+    @impl Pleroma.Migrators.Support.BaseMigratorState
+    defdelegate data_migration(), to: Pleroma.DataMigration, as: :delete_context_objects
+  end
+
+  use Pleroma.Migrators.Support.BaseMigrator
+
+  alias Pleroma.Migrators.Support.BaseMigrator
+  alias Pleroma.Object
+
+  @doc "This migration removes objects created exclusively for contexts, containing only an `id` field."
+
+  @impl BaseMigrator
+  def feature_config_path, do: [:features, :delete_context_objects]
+
+  @impl BaseMigrator
+  def fault_rate_allowance, do: Config.get([:delete_context_objects, :fault_rate_allowance], 0)
+
+  @impl BaseMigrator
+  def perform do
+    data_migration_id = data_migration_id()
+    max_processed_id = get_stat(:max_processed_id, 0)
+
+    Logger.info("Deleting context objects from `objects` (from oid: #{max_processed_id})...")
+
+    query()
+    |> where([object], object.id > ^max_processed_id)
+    |> Repo.chunk_stream(100, :batches, timeout: :infinity)
+    |> Stream.each(fn objects ->
+      object_ids = Enum.map(objects, & &1.id)
+
+      results = Enum.map(object_ids, &delete_context_object(&1))
+
+      failed_ids =
+        results
+        |> Enum.filter(&(elem(&1, 0) == :error))
+        |> Enum.map(&elem(&1, 1))
+
+      chunk_affected_count =
+        results
+        |> Enum.filter(&(elem(&1, 0) == :ok))
+        |> length()
+
+      for failed_id <- failed_ids do
+        _ =
+          Repo.query(
+            "INSERT INTO data_migration_failed_ids(data_migration_id, record_id) " <>
+              "VALUES ($1, $2) ON CONFLICT DO NOTHING;",
+            [data_migration_id, failed_id]
+          )
+      end
+
+      _ =
+        Repo.query(
+          "DELETE FROM data_migration_failed_ids " <>
+            "WHERE data_migration_id = $1 AND record_id = ANY($2)",
+          [data_migration_id, object_ids -- failed_ids]
+        )
+
+      max_object_id = Enum.at(object_ids, -1)
+
+      put_stat(:max_processed_id, max_object_id)
+      increment_stat(:iteration_processed_count, length(object_ids))
+      increment_stat(:processed_count, length(object_ids))
+      increment_stat(:failed_count, length(failed_ids))
+      increment_stat(:affected_count, chunk_affected_count)
+      put_stat(:records_per_second, records_per_second())
+      persist_state()
+
+      # A quick and dirty approach to controlling the load this background migration imposes
+      sleep_interval = Config.get([:delete_context_objects, :sleep_interval_ms], 0)
+      Process.sleep(sleep_interval)
+    end)
+    |> Stream.run()
+  end
+
+  @impl BaseMigrator
+  def query do
+    # Context objects have no activity type, and only one field, `id`.
+    # Only those context objects are without types.
+    from(
+      object in Object,
+      where: fragment("(?)->'type' IS NULL", object.data),
+      select: %{
+        id: object.id
+      }
+    )
+  end
+
+  @spec delete_context_object(integer()) :: {:ok | :error, integer()}
+  defp delete_context_object(id) do
+    result =
+      %Object{id: id}
+      |> Repo.delete()
+      |> elem(0)
+
+    {result, id}
+  end
+
+  @impl BaseMigrator
+  def retry_failed do
+    data_migration_id = data_migration_id()
+
+    failed_objects_query()
+    |> Repo.chunk_stream(100, :one)
+    |> Stream.each(fn object ->
+      with {res, _} when res != :error <- delete_context_object(object.id) do
+        _ =
+          Repo.query(
+            "DELETE FROM data_migration_failed_ids " <>
+              "WHERE data_migration_id = $1 AND record_id = $2",
+            [data_migration_id, object.id]
+          )
+      end
+    end)
+    |> Stream.run()
+
+    put_stat(:failed_count, failures_count())
+    persist_state()
+
+    force_continue()
+  end
+
+  defp failed_objects_query do
+    from(o in Object)
+    |> join(:inner, [o], dmf in fragment("SELECT * FROM data_migration_failed_ids"),
+      on: dmf.record_id == o.id
+    )
+    |> where([_o, dmf], dmf.data_migration_id == ^data_migration_id())
+    |> order_by([o], asc: o.id)
+  end
+end
diff --git a/lib/pleroma/object.ex b/lib/pleroma/object.ex
index e7d0d52b0..fee3f1842 100644
--- a/lib/pleroma/object.ex
+++ b/lib/pleroma/object.ex
@@ -207,10 +207,6 @@ defmodule Pleroma.Object do
     end
   end
 
-  def context_mapping(context) do
-    Object.change(%Object{}, %{data: %{"id" => context}})
-  end
-
   def make_tombstone(%Object{data: %{"id" => id, "type" => type}}, deleted \\ DateTime.utc_now()) do
     %ObjectTombstone{
       id: id,
diff --git a/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex b/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex
index 027979a32..5647156f5 100644
--- a/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex
@@ -97,7 +97,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidator do
   defp validate_data(data_cng) do
     data_cng
     |> validate_inclusion(:type, ["Article", "Note", "Page"])
-    |> validate_required([:id, :actor, :attributedTo, :type, :context, :context_id])
+    |> validate_required([:id, :actor, :attributedTo, :type, :context])
     |> CommonValidations.validate_any_presence([:cc, :to])
     |> CommonValidations.validate_fields_match([:actor, :attributedTo])
     |> CommonValidations.validate_actor_presence()
diff --git a/lib/pleroma/web/activity_pub/object_validators/common_fields.ex b/lib/pleroma/web/activity_pub/object_validators/common_fields.ex
index a59a6e545..7b60c139a 100644
--- a/lib/pleroma/web/activity_pub/object_validators/common_fields.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/common_fields.ex
@@ -52,8 +52,6 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFields do
       field(:summary, :string)
 
       field(:context, :string)
-      # short identifier for PleromaFE to group statuses by context
-      field(:context_id, :integer)
 
       field(:sensitive, :boolean, default: false)
       field(:replies_count, :integer, default: 0)
diff --git a/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex b/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex
index 4f8c083eb..add46d561 100644
--- a/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex
@@ -22,14 +22,15 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
   end
 
   def fix_object_defaults(data) do
-    %{data: %{"id" => context}, id: context_id} =
-      Utils.create_context(data["context"] || data["conversation"])
+    context =
+      Utils.maybe_create_context(
+        data["context"] || data["conversation"] || data["inReplyTo"] || data["id"]
+      )
 
     %User{follower_address: follower_collection} = User.get_cached_by_ap_id(data["attributedTo"])
 
     data
     |> Map.put("context", context)
-    |> Map.put("context_id", context_id)
     |> cast_and_filter_recipients("to", follower_collection)
     |> cast_and_filter_recipients("cc", follower_collection)
     |> cast_and_filter_recipients("bto", follower_collection)
diff --git a/lib/pleroma/web/activity_pub/object_validators/create_generic_validator.ex b/lib/pleroma/web/activity_pub/object_validators/create_generic_validator.ex
index c9a621cb1..2395abfd4 100644
--- a/lib/pleroma/web/activity_pub/object_validators/create_generic_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/create_generic_validator.ex
@@ -75,7 +75,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CreateGenericValidator do
 
     data
     |> CommonFixes.fix_actor()
-    |> Map.put_new("context", object["context"])
+    |> Map.put("context", object["context"])
     |> fix_addressing(object)
   end
 
diff --git a/lib/pleroma/web/activity_pub/object_validators/event_validator.ex b/lib/pleroma/web/activity_pub/object_validators/event_validator.ex
index 0e99f2037..ab204f69a 100644
--- a/lib/pleroma/web/activity_pub/object_validators/event_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/event_validator.ex
@@ -62,7 +62,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.EventValidator do
   defp validate_data(data_cng) do
     data_cng
     |> validate_inclusion(:type, ["Event"])
-    |> validate_required([:id, :actor, :attributedTo, :type, :context, :context_id])
+    |> validate_required([:id, :actor, :attributedTo, :type, :context])
     |> CommonValidations.validate_any_presence([:cc, :to])
     |> CommonValidations.validate_fields_match([:actor, :attributedTo])
     |> CommonValidations.validate_actor_presence()
diff --git a/lib/pleroma/web/activity_pub/object_validators/question_validator.ex b/lib/pleroma/web/activity_pub/object_validators/question_validator.ex
index 9412be4bc..ce3305142 100644
--- a/lib/pleroma/web/activity_pub/object_validators/question_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/question_validator.ex
@@ -80,7 +80,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.QuestionValidator do
   defp validate_data(data_cng) do
     data_cng
     |> validate_inclusion(:type, ["Question"])
-    |> validate_required([:id, :actor, :attributedTo, :type, :context, :context_id])
+    |> validate_required([:id, :actor, :attributedTo, :type, :context])
     |> CommonValidations.validate_any_presence([:cc, :to])
     |> CommonValidations.validate_fields_match([:actor, :attributedTo])
     |> CommonValidations.validate_actor_presence()
diff --git a/lib/pleroma/web/activity_pub/utils.ex b/lib/pleroma/web/activity_pub/utils.ex
index 9cde7805c..d3b7d804f 100644
--- a/lib/pleroma/web/activity_pub/utils.ex
+++ b/lib/pleroma/web/activity_pub/utils.ex
@@ -154,22 +154,7 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     Notification.get_notified_from_activity(%Activity{data: object}, false)
   end
 
-  def create_context(context) do
-    context = context || generate_id("contexts")
-
-    # Ecto has problems accessing the constraint inside the jsonb,
-    # so we explicitly check for the existed object before insert
-    object = Object.get_cached_by_ap_id(context)
-
-    with true <- is_nil(object),
-         changeset <- Object.context_mapping(context),
-         {:ok, inserted_object} <- Repo.insert(changeset) do
-      inserted_object
-    else
-      _ ->
-        object
-    end
-  end
+  def maybe_create_context(context), do: context || generate_id("contexts")
 
   @doc """
   Enqueues an activity for federation if it's local
@@ -201,18 +186,16 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     |> Map.put_new("id", "pleroma:fakeid")
     |> Map.put_new_lazy("published", &make_date/0)
     |> Map.put_new("context", "pleroma:fakecontext")
-    |> Map.put_new("context_id", -1)
     |> lazy_put_object_defaults(true)
   end
 
   def lazy_put_activity_defaults(map, _fake?) do
-    %{data: %{"id" => context}, id: context_id} = create_context(map["context"])
+    context = maybe_create_context(map["context"])
 
     map
     |> Map.put_new_lazy("id", &generate_activity_id/0)
     |> Map.put_new_lazy("published", &make_date/0)
     |> Map.put_new("context", context)
-    |> Map.put_new("context_id", context_id)
     |> lazy_put_object_defaults(false)
   end
 
@@ -226,7 +209,6 @@ defmodule Pleroma.Web.ActivityPub.Utils do
       |> Map.put_new("id", "pleroma:fake_object_id")
       |> Map.put_new_lazy("published", &make_date/0)
       |> Map.put_new("context", activity["context"])
-      |> Map.put_new("context_id", activity["context_id"])
       |> Map.put_new("fake", true)
 
     %{activity | "object" => object}
@@ -239,7 +221,6 @@ defmodule Pleroma.Web.ActivityPub.Utils do
       |> Map.put_new_lazy("id", &generate_object_id/0)
       |> Map.put_new_lazy("published", &make_date/0)
       |> Map.put_new("context", activity["context"])
-      |> Map.put_new("context_id", activity["context_id"])
 
     %{activity | "object" => object}
   end
diff --git a/lib/pleroma/web/api_spec/schemas/status.ex b/lib/pleroma/web/api_spec/schemas/status.ex
index f803caec2..698f11794 100644
--- a/lib/pleroma/web/api_spec/schemas/status.ex
+++ b/lib/pleroma/web/api_spec/schemas/status.ex
@@ -148,9 +148,15 @@ defmodule Pleroma.Web.ApiSpec.Schemas.Status do
             description:
               "A map consisting of alternate representations of the `content` property with the key being it's mimetype. Currently the only alternate representation supported is `text/plain`"
           },
+          context: %Schema{
+            type: :string,
+            description: "The thread identifier the status is associated with"
+          },
           conversation_id: %Schema{
             type: :integer,
-            description: "The ID of the AP context the status is associated with (if any)"
+            deprecated: true,
+            description:
+              "The ID of the AP context the status is associated with (if any); deprecated, please use `context` instead"
           },
           direct_conversation_id: %Schema{
             type: :integer,
@@ -325,6 +331,7 @@ defmodule Pleroma.Web.ApiSpec.Schemas.Status do
       "pinned" => false,
       "pleroma" => %{
         "content" => %{"text/plain" => "foobar"},
+        "context" => "http://localhost:4001/objects/8b4c0c80-6a37-4d2a-b1b9-05a19e3875aa",
         "conversation_id" => 345_972,
         "direct_conversation_id" => nil,
         "emoji_reactions" => [],
diff --git a/lib/pleroma/web/common_api/utils.ex b/lib/pleroma/web/common_api/utils.ex
index 5fc8c3220..ff0814329 100644
--- a/lib/pleroma/web/common_api/utils.ex
+++ b/lib/pleroma/web/common_api/utils.ex
@@ -453,35 +453,6 @@ defmodule Pleroma.Web.CommonAPI.Utils do
 
   def get_report_statuses(_, _), do: {:ok, nil}
 
-  # DEPRECATED mostly, context objects are now created at insertion time.
-  def context_to_conversation_id(context) do
-    with %Object{id: id} <- Object.get_cached_by_ap_id(context) do
-      id
-    else
-      _e ->
-        changeset = Object.context_mapping(context)
-
-        case Repo.insert(changeset) do
-          {:ok, %{id: id}} ->
-            id
-
-          # This should be solved by an upsert, but it seems ecto
-          # has problems accessing the constraint inside the jsonb.
-          {:error, _} ->
-            Object.get_cached_by_ap_id(context).id
-        end
-    end
-  end
-
-  def conversation_id_to_context(id) do
-    with %Object{data: %{"id" => context}} <- Repo.get(Object, id) do
-      context
-    else
-      _e ->
-        {:error, dgettext("errors", "No such conversation")}
-    end
-  end
-
   def validate_character_limit("" = _full_payload, [] = _attachments) do
     {:error, dgettext("errors", "Cannot post an empty status without attachments")}
   end
diff --git a/lib/pleroma/web/mastodon_api/views/status_view.ex b/lib/pleroma/web/mastodon_api/views/status_view.ex
index 54e025aae..b949d8f9a 100644
--- a/lib/pleroma/web/mastodon_api/views/status_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/status_view.ex
@@ -57,11 +57,19 @@ defmodule Pleroma.Web.MastodonAPI.StatusView do
     end)
   end
 
-  defp get_context_id(%{data: %{"context_id" => context_id}}) when not is_nil(context_id),
-    do: context_id
-
-  defp get_context_id(%{data: %{"context" => context}}) when is_binary(context),
-    do: Utils.context_to_conversation_id(context)
+  # DEPRECATED This field seems to be a left-over from the StatusNet era.
+  # If your application uses `pleroma.conversation_id`: this field is deprecated.
+  # It is currently stubbed instead by doing a CRC32 of the context, and
+  # clearing the MSB to avoid overflow exceptions with signed integers on the
+  # different clients using this field (Java/Kotlin code, mostly; see Husky.)
+  # This should be removed in a future version of Pleroma. Pleroma-FE currently
+  # depends on this field, as well.
+  defp get_context_id(%{data: %{"context" => context}}) when is_binary(context) do
+    use Bitwise
+
+    :erlang.crc32(context)
+    |> band(bnot(0x8000_0000))
+  end
 
   defp get_context_id(_), do: nil
 
@@ -388,6 +396,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusView do
       pleroma: %{
         local: activity.local,
         conversation_id: get_context_id(activity),
+        context: object.data["context"],
         in_reply_to_account_acct: reply_to_user && reply_to_user.nickname,
         content: %{"text/plain" => content_plaintext},
         spoiler_text: %{"text/plain" => summary},
diff --git a/priv/repo/migrations/20220807125023_data_migration_delete_context_objects.exs b/priv/repo/migrations/20220807125023_data_migration_delete_context_objects.exs
new file mode 100644
index 000000000..84365dbe3
--- /dev/null
+++ b/priv/repo/migrations/20220807125023_data_migration_delete_context_objects.exs
@@ -0,0 +1,18 @@
+defmodule Pleroma.Repo.Migrations.DataMigrationDeleteContextObjects do
+  use Ecto.Migration
+
+  require Logger
+
+  def up do
+    dt = NaiveDateTime.utc_now()
+
+    execute(
+      "INSERT INTO data_migrations(name, inserted_at, updated_at) " <>
+        "VALUES ('delete_context_objects', '#{dt}', '#{dt}') ON CONFLICT DO NOTHING;"
+    )
+  end
+
+  def down do
+    execute("DELETE FROM data_migrations WHERE name = 'delete_context_objects';")
+  end
+end
diff --git a/test/fixtures/create-pleroma-reply-to-misskey-thread.json b/test/fixtures/create-pleroma-reply-to-misskey-thread.json
new file mode 100644
index 000000000..0c31efa76
--- /dev/null
+++ b/test/fixtures/create-pleroma-reply-to-misskey-thread.json
@@ -0,0 +1,61 @@
+{
+    "@context": [
+        "https://www.w3.org/ns/activitystreams",
+        "https://p.helene.moe/schemas/litepub-0.1.jsonld",
+        {
+            "@language": "und"
+        }
+    ],
+    "actor": "https://p.helene.moe/users/helene",
+    "attachment": [],
+    "attributedTo": "https://p.helene.moe/users/helene",
+    "cc": [
+        "https://p.helene.moe/users/helene/followers"
+    ],
+    "context": "https://p.helene.moe/contexts/cc324643-5583-4c3f-91d2-c6ed37db159d",
+    "conversation": "https://p.helene.moe/contexts/cc324643-5583-4c3f-91d2-c6ed37db159d",
+    "directMessage": false,
+    "id": "https://p.helene.moe/activities/5f80db86-a9bb-4883-9845-fbdbd1478f3a",
+    "object": {
+        "actor": "https://p.helene.moe/users/helene",
+        "attachment": [],
+        "attributedTo": "https://p.helene.moe/users/helene",
+        "cc": [
+            "https://p.helene.moe/users/helene/followers"
+        ],
+        "content": "<span class=\"h-card\"><a class=\"u-url mention\" data-user=\"AHntpQ4T3J4OSnpgMC\" href=\"https://mk.absturztau.be/@mametsuko\" rel=\"ugc\">@<span>mametsuko</span></a></span> meow",
+        "context": "https://p.helene.moe/contexts/cc324643-5583-4c3f-91d2-c6ed37db159d",
+        "conversation": "https://p.helene.moe/contexts/cc324643-5583-4c3f-91d2-c6ed37db159d",
+        "id": "https://p.helene.moe/objects/fd5910ac-d9dc-412e-8d1d-914b203296c4",
+        "inReplyTo": "https://mk.absturztau.be/notes/93e7nm8wqg",
+        "published": "2022-08-02T13:46:58.403996Z",
+        "sensitive": null,
+        "source": "@mametsuko@mk.absturztau.be meow",
+        "summary": "",
+        "tag": [
+            {
+                "href": "https://mk.absturztau.be/users/8ozbzjs3o8",
+                "name": "@mametsuko@mk.absturztau.be",
+                "type": "Mention"
+            }
+        ],
+        "to": [
+            "https://mk.absturztau.be/users/8ozbzjs3o8",
+            "https://www.w3.org/ns/activitystreams#Public"
+        ],
+        "type": "Note"
+    },
+    "published": "2022-08-02T13:46:58.403883Z",
+    "tag": [
+        {
+            "href": "https://mk.absturztau.be/users/8ozbzjs3o8",
+            "name": "@mametsuko@mk.absturztau.be",
+            "type": "Mention"
+        }
+    ],
+    "to": [
+        "https://mk.absturztau.be/users/8ozbzjs3o8",
+        "https://www.w3.org/ns/activitystreams#Public"
+    ],
+    "type": "Create"
+}
\ No newline at end of file
diff --git a/test/fixtures/tesla_mock/helene@p.helene.moe.json b/test/fixtures/tesla_mock/helene@p.helene.moe.json
new file mode 100644
index 000000000..d7444817f
--- /dev/null
+++ b/test/fixtures/tesla_mock/helene@p.helene.moe.json
@@ -0,0 +1,50 @@
+{
+    "@context": [
+        "https://www.w3.org/ns/activitystreams",
+        "https://p.helene.moe/schemas/litepub-0.1.jsonld",
+        {
+            "@language": "und"
+        }
+    ],
+    "alsoKnownAs": [],
+    "attachment": [
+        {
+            "name": "Timezone",
+            "type": "PropertyValue",
+            "value": "UTC+2 (Paris/Berlin)"
+        }
+    ],
+    "capabilities": {
+        "acceptsChatMessages": true
+    },
+    "discoverable": true,
+    "endpoints": {
+        "oauthAuthorizationEndpoint": "https://p.helene.moe/oauth/authorize",
+        "oauthRegistrationEndpoint": "https://p.helene.moe/api/v1/apps",
+        "oauthTokenEndpoint": "https://p.helene.moe/oauth/token",
+        "sharedInbox": "https://p.helene.moe/inbox",
+        "uploadMedia": "https://p.helene.moe/api/ap/upload_media"
+    },
+    "featured": "https://p.helene.moe/users/helene/collections/featured",
+    "followers": "https://p.helene.moe/users/helene/followers",
+    "following": "https://p.helene.moe/users/helene/following",
+    "icon": {
+        "type": "Image",
+        "url": "https://p.helene.moe/media/9a39209daa5a66b7ebb0547b08bf8360aa9d8d65a4ffba2603c6ffbe6aecb432.jpg"
+    },
+    "id": "https://p.helene.moe/users/helene",
+    "inbox": "https://p.helene.moe/users/helene/inbox",
+    "manuallyApprovesFollowers": false,
+    "name": "Hélène",
+    "outbox": "https://p.helene.moe/users/helene/outbox",
+    "preferredUsername": "helene",
+    "publicKey": {
+        "id": "https://p.helene.moe/users/helene#main-key",
+        "owner": "https://p.helene.moe/users/helene",
+        "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtoSBPU/VS2Kx3f6ap3zv\nZVacJsgUfaoFb3c2ii/FRh9RmRVlarq8sJXcjsQt1e0oxWaWJaIDDwyKZPt6hXae\nrY/AiGGeNu+NA+BtY7l7+9Yu67HUyT62+1qAwYHKBXX3fLOPs/YmQI0Tt0c4wKAG\nKEkiYsRizghgpzUC6jqdKV71DJkUZ8yhckCGb2fLko1ajbWEssdaP51aLsyRMyC2\nuzeWrxtD4O/HG0ea4S6y5X6hnsAHIK4Y3nnyIQ6pn4tOsl3HgqkjXE9MmZSvMCFx\nBq89TfZrVXNa2gSZdZLdbbJstzEScQWNt1p6tA6rM+e4JXYGr+rMdF3G+jV7afI2\nFQIDAQAB\n-----END PUBLIC KEY-----\n\n"
+    },
+    "summary": "I can speak: Français, English, Deutsch (nicht sehr gut), 日本語 (not very well)",
+    "tag": [],
+    "type": "Person",
+    "url": "https://p.helene.moe/users/helene"
+}
\ No newline at end of file
diff --git a/test/fixtures/tesla_mock/mametsuko@mk.absturztau.be.json b/test/fixtures/tesla_mock/mametsuko@mk.absturztau.be.json
new file mode 100644
index 000000000..d8c13f775
--- /dev/null
+++ b/test/fixtures/tesla_mock/mametsuko@mk.absturztau.be.json
@@ -0,0 +1,65 @@
+{
+    "@context": [
+        "https://www.w3.org/ns/activitystreams",
+        "https://w3id.org/security/v1",
+        {
+            "manuallyApprovesFollowers": "as:manuallyApprovesFollowers",
+            "sensitive": "as:sensitive",
+            "Hashtag": "as:Hashtag",
+            "quoteUrl": "as:quoteUrl",
+            "toot": "http://joinmastodon.org/ns#",
+            "Emoji": "toot:Emoji",
+            "featured": "toot:featured",
+            "discoverable": "toot:discoverable",
+            "schema": "http://schema.org#",
+            "PropertyValue": "schema:PropertyValue",
+            "value": "schema:value",
+            "misskey": "https://misskey-hub.net/ns#",
+            "_misskey_content": "misskey:_misskey_content",
+            "_misskey_quote": "misskey:_misskey_quote",
+            "_misskey_reaction": "misskey:_misskey_reaction",
+            "_misskey_votes": "misskey:_misskey_votes",
+            "_misskey_talk": "misskey:_misskey_talk",
+            "isCat": "misskey:isCat",
+            "vcard": "http://www.w3.org/2006/vcard/ns#"
+        }
+    ],
+    "type": "Person",
+    "id": "https://mk.absturztau.be/users/8ozbzjs3o8",
+    "inbox": "https://mk.absturztau.be/users/8ozbzjs3o8/inbox",
+    "outbox": "https://mk.absturztau.be/users/8ozbzjs3o8/outbox",
+    "followers": "https://mk.absturztau.be/users/8ozbzjs3o8/followers",
+    "following": "https://mk.absturztau.be/users/8ozbzjs3o8/following",
+    "featured": "https://mk.absturztau.be/users/8ozbzjs3o8/collections/featured",
+    "sharedInbox": "https://mk.absturztau.be/inbox",
+    "endpoints": {
+        "sharedInbox": "https://mk.absturztau.be/inbox"
+    },
+    "url": "https://mk.absturztau.be/@mametsuko",
+    "preferredUsername": "mametsuko",
+    "name": "mametschko",
+    "summary": "<p><span>nya, ich bin eine Brotperson</span></p>",
+    "icon": {
+        "type": "Image",
+        "url": "https://mk.absturztau.be/files/webpublic-3b5594f4-fa52-4548-b4e3-c379ae2143ed",
+        "sensitive": false,
+        "name": null
+    },
+    "image": {
+        "type": "Image",
+        "url": "https://mk.absturztau.be/files/webpublic-0d03b03d-b14b-4916-ac3d-8a137118ec84",
+        "sensitive": false,
+        "name": null
+    },
+    "tag": [],
+    "manuallyApprovesFollowers": true,
+    "discoverable": false,
+    "publicKey": {
+        "id": "https://mk.absturztau.be/users/8ozbzjs3o8#main-key",
+        "type": "Key",
+        "owner": "https://mk.absturztau.be/users/8ozbzjs3o8",
+        "publicKeyPem": "-----BEGIN PUBLIC KEY-----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\nZK1YlAERG2XFO6br8omhcmECAwEAAQ==\n-----END PUBLIC KEY-----\n"
+    },
+    "isCat": true,
+    "vcard:Address": "Vienna, Austria"
+}
\ No newline at end of file
diff --git a/test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg-activity.json b/test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg-activity.json
new file mode 100644
index 000000000..b45ab78e4
--- /dev/null
+++ b/test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg-activity.json
@@ -0,0 +1 @@
+{"@context":["https://www.w3.org/ns/activitystreams","https://w3id.org/security/v1",{"manuallyApprovesFollowers":"as:manuallyApprovesFollowers","sensitive":"as:sensitive","Hashtag":"as:Hashtag","quoteUrl":"as:quoteUrl","toot":"http://joinmastodon.org/ns#","Emoji":"toot:Emoji","featured":"toot:featured","discoverable":"toot:discoverable","schema":"http://schema.org#","PropertyValue":"schema:PropertyValue","value":"schema:value","misskey":"https://misskey-hub.net/ns#","_misskey_content":"misskey:_misskey_content","_misskey_quote":"misskey:_misskey_quote","_misskey_reaction":"misskey:_misskey_reaction","_misskey_votes":"misskey:_misskey_votes","_misskey_talk":"misskey:_misskey_talk","isCat":"misskey:isCat","vcard":"http://www.w3.org/2006/vcard/ns#"}],"id":"https://mk.absturztau.be/notes/93e7nm8wqg/activity","actor":"https://mk.absturztau.be/users/8ozbzjs3o8","type":"Create","published":"2022-08-01T11:06:49.568Z","object":{"id":"https://mk.absturztau.be/notes/93e7nm8wqg","type":"Note","attributedTo":"https://mk.absturztau.be/users/8ozbzjs3o8","summary":null,"content":"<p><span>meow</span></p>","_misskey_content":"meow","published":"2022-08-01T11:06:49.568Z","to":["https://www.w3.org/ns/activitystreams#Public"],"cc":["https://mk.absturztau.be/users/8ozbzjs3o8/followers"],"inReplyTo":null,"attachment":[],"sensitive":false,"tag":[]},"to":["https://www.w3.org/ns/activitystreams#Public"],"cc":["https://mk.absturztau.be/users/8ozbzjs3o8/followers"]}
\ No newline at end of file
diff --git a/test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg.json b/test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg.json
new file mode 100644
index 000000000..1b931a9a4
--- /dev/null
+++ b/test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg.json
@@ -0,0 +1,44 @@
+{
+    "@context": [
+        "https://www.w3.org/ns/activitystreams",
+        "https://w3id.org/security/v1",
+        {
+            "manuallyApprovesFollowers": "as:manuallyApprovesFollowers",
+            "sensitive": "as:sensitive",
+            "Hashtag": "as:Hashtag",
+            "quoteUrl": "as:quoteUrl",
+            "toot": "http://joinmastodon.org/ns#",
+            "Emoji": "toot:Emoji",
+            "featured": "toot:featured",
+            "discoverable": "toot:discoverable",
+            "schema": "http://schema.org#",
+            "PropertyValue": "schema:PropertyValue",
+            "value": "schema:value",
+            "misskey": "https://misskey-hub.net/ns#",
+            "_misskey_content": "misskey:_misskey_content",
+            "_misskey_quote": "misskey:_misskey_quote",
+            "_misskey_reaction": "misskey:_misskey_reaction",
+            "_misskey_votes": "misskey:_misskey_votes",
+            "_misskey_talk": "misskey:_misskey_talk",
+            "isCat": "misskey:isCat",
+            "vcard": "http://www.w3.org/2006/vcard/ns#"
+        }
+    ],
+    "id": "https://mk.absturztau.be/notes/93e7nm8wqg",
+    "type": "Note",
+    "attributedTo": "https://mk.absturztau.be/users/8ozbzjs3o8",
+    "summary": null,
+    "content": "<p><span>meow</span></p>",
+    "_misskey_content": "meow",
+    "published": "2022-08-01T11:06:49.568Z",
+    "to": [
+        "https://www.w3.org/ns/activitystreams#Public"
+    ],
+    "cc": [
+        "https://mk.absturztau.be/users/8ozbzjs3o8/followers"
+    ],
+    "inReplyTo": null,
+    "attachment": [],
+    "sensitive": false,
+    "tag": []
+}
\ No newline at end of file
diff --git a/test/fixtures/tesla_mock/p.helene.moe-AM7S6vZQmL6pI9TgPY.json b/test/fixtures/tesla_mock/p.helene.moe-AM7S6vZQmL6pI9TgPY.json
new file mode 100644
index 000000000..a1ef5e20b
--- /dev/null
+++ b/test/fixtures/tesla_mock/p.helene.moe-AM7S6vZQmL6pI9TgPY.json
@@ -0,0 +1,36 @@
+{
+    "@context": [
+        "https://www.w3.org/ns/activitystreams",
+        "https://p.helene.moe/schemas/litepub-0.1.jsonld",
+        {
+            "@language": "und"
+        }
+    ],
+    "actor": "https://p.helene.moe/users/helene",
+    "attachment": [],
+    "attributedTo": "https://p.helene.moe/users/helene",
+    "cc": [
+        "https://p.helene.moe/users/helene/followers"
+    ],
+    "content": "<span class=\"h-card\"><a class=\"u-url mention\" data-user=\"AHntpQ4T3J4OSnpgMC\" href=\"https://mk.absturztau.be/@mametsuko\" rel=\"ugc\">@<span>mametsuko</span></a></span> meow",
+    "context": "https://p.helene.moe/contexts/cc324643-5583-4c3f-91d2-c6ed37db159d",
+    "conversation": "https://p.helene.moe/contexts/cc324643-5583-4c3f-91d2-c6ed37db159d",
+    "id": "https://p.helene.moe/objects/fd5910ac-d9dc-412e-8d1d-914b203296c4",
+    "inReplyTo": "https://mk.absturztau.be/notes/93e7nm8wqg",
+    "published": "2022-08-02T13:46:58.403996Z",
+    "sensitive": null,
+    "source": "@mametsuko@mk.absturztau.be meow",
+    "summary": "",
+    "tag": [
+        {
+            "href": "https://mk.absturztau.be/users/8ozbzjs3o8",
+            "name": "@mametsuko@mk.absturztau.be",
+            "type": "Mention"
+        }
+    ],
+    "to": [
+        "https://mk.absturztau.be/users/8ozbzjs3o8",
+        "https://www.w3.org/ns/activitystreams#Public"
+    ],
+    "type": "Note"
+}
\ No newline at end of file
diff --git a/test/pleroma/web/activity_pub/activity_pub_test.exs b/test/pleroma/web/activity_pub/activity_pub_test.exs
index 4d7e76266..b8d73ea10 100644
--- a/test/pleroma/web/activity_pub/activity_pub_test.exs
+++ b/test/pleroma/web/activity_pub/activity_pub_test.exs
@@ -554,7 +554,6 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
       assert activity.data["ok"] == data["ok"]
       assert activity.data["id"] == given_id
       assert activity.data["context"] == "blabla"
-      assert activity.data["context_id"]
     end
 
     test "adds a context when none is there" do
@@ -576,8 +575,6 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
 
       assert is_binary(activity.data["context"])
       assert is_binary(object.data["context"])
-      assert activity.data["context_id"]
-      assert object.data["context_id"]
     end
 
     test "adds an id to a given object if it lacks one and is a note and inserts it to the object database" do
@@ -1612,7 +1609,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubTest do
                })
 
       assert Repo.aggregate(Activity, :count, :id) == 1
-      assert Repo.aggregate(Object, :count, :id) == 2
+      assert Repo.aggregate(Object, :count, :id) == 1
       assert Repo.aggregate(Notification, :count, :id) == 0
     end
   end
diff --git a/test/pleroma/web/activity_pub/object_validators/create_generic_validator_test.exs b/test/pleroma/web/activity_pub/object_validators/create_generic_validator_test.exs
index 0a5b44beb..e771260c9 100644
--- a/test/pleroma/web/activity_pub/object_validators/create_generic_validator_test.exs
+++ b/test/pleroma/web/activity_pub/object_validators/create_generic_validator_test.exs
@@ -23,10 +23,10 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CreateGenericValidatorTest do
     {:ok, object_data} = ObjectValidator.cast_and_apply(note_activity["object"])
     meta = [object_data: ObjectValidator.stringify_keys(object_data)]
 
-    %{valid?: true} = CreateGenericValidator.cast_and_validate(note_activity, meta)
+    assert %{valid?: true} = CreateGenericValidator.cast_and_validate(note_activity, meta)
   end
 
-  test "a Create/Note with mismatched context is invalid" do
+  test "a Create/Note with mismatched context uses the Note's context" do
     user = insert(:user)
 
     note = %{
@@ -54,6 +54,9 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CreateGenericValidatorTest do
     {:ok, object_data} = ObjectValidator.cast_and_apply(note_activity["object"])
     meta = [object_data: ObjectValidator.stringify_keys(object_data)]
 
-    %{valid?: false} = CreateGenericValidator.cast_and_validate(note_activity, meta)
+    validated = CreateGenericValidator.cast_and_validate(note_activity, meta)
+
+    assert validated.valid?
+    assert {:context, note["context"]} in validated.changes
   end
 end
diff --git a/test/pleroma/web/activity_pub/transmogrifier/note_handling_test.exs b/test/pleroma/web/activity_pub/transmogrifier/note_handling_test.exs
index b00fd919b..7c406fbd0 100644
--- a/test/pleroma/web/activity_pub/transmogrifier/note_handling_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier/note_handling_test.exs
@@ -707,4 +707,42 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier.NoteHandlingTest do
              }
            ]
   end
+
+  test "the standalone note uses its own ID when context is missing" do
+    insert(:user, ap_id: "https://mk.absturztau.be/users/8ozbzjs3o8")
+
+    activity =
+      "test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg-activity.json"
+      |> File.read!()
+      |> Jason.decode!()
+
+    {:ok, %Activity{} = modified} = Transmogrifier.handle_incoming(activity)
+    object = Object.normalize(modified, fetch: false)
+
+    assert object.data["context"] == object.data["id"]
+    assert modified.data["context"] == object.data["id"]
+  end
+
+  test "the reply note uses its parent's ID when context is missing and reply is unreachable" do
+    insert(:user, ap_id: "https://mk.absturztau.be/users/8ozbzjs3o8")
+
+    activity =
+      "test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg-activity.json"
+      |> File.read!()
+      |> Jason.decode!()
+
+    object =
+      activity["object"]
+      |> Map.put("inReplyTo", "https://404.site/object/went-to-buy-milk")
+
+    activity =
+      activity
+      |> Map.put("object", object)
+
+    {:ok, %Activity{} = modified} = Transmogrifier.handle_incoming(activity)
+    object = Object.normalize(modified, fetch: false)
+
+    assert object.data["context"] == object.data["inReplyTo"]
+    assert modified.data["context"] == object.data["inReplyTo"]
+  end
 end
diff --git a/test/pleroma/web/activity_pub/transmogrifier/question_handling_test.exs b/test/pleroma/web/activity_pub/transmogrifier/question_handling_test.exs
index d22ec400d..d31070546 100644
--- a/test/pleroma/web/activity_pub/transmogrifier/question_handling_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier/question_handling_test.exs
@@ -33,8 +33,6 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier.QuestionHandlingTest do
     assert object.data["context"] ==
              "tag:mastodon.sdf.org,2019-05-10:objectId=15095122:objectType=Conversation"
 
-    assert object.data["context_id"]
-
     assert object.data["anyOf"] == []
 
     assert Enum.sort(object.data["oneOf"]) ==
@@ -68,7 +66,6 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier.QuestionHandlingTest do
     reply_object = Object.normalize(reply_activity, fetch: false)
 
     assert reply_object.data["context"] == object.data["context"]
-    assert reply_object.data["context_id"] == object.data["context_id"]
   end
 
   test "Mastodon Question activity with HTML tags in plaintext" do
diff --git a/test/pleroma/web/activity_pub/transmogrifier_test.exs b/test/pleroma/web/activity_pub/transmogrifier_test.exs
index 6520eabc9..273f2611d 100644
--- a/test/pleroma/web/activity_pub/transmogrifier_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier_test.exs
@@ -108,15 +108,20 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert activity.data["type"] == "Move"
     end
 
-    test "a reply with mismatched context is rejected" do
-      insert(:user, ap_id: "https://macgirvin.com/channel/mike")
+    test "it fixes both the Create and object contexts in a reply" do
+      insert(:user, ap_id: "https://mk.absturztau.be/users/8ozbzjs3o8")
+      insert(:user, ap_id: "https://p.helene.moe/users/helene")
 
-      note_activity =
-        "test/fixtures/roadhouse-create-activity.json"
+      create_activity =
+        "test/fixtures/create-pleroma-reply-to-misskey-thread.json"
         |> File.read!()
         |> Jason.decode!()
 
-      assert {:error, _} = Transmogrifier.handle_incoming(note_activity)
+      assert {:ok, %Activity{} = activity} = Transmogrifier.handle_incoming(create_activity)
+
+      object = Object.normalize(activity, fetch: false)
+
+      assert activity.data["context"] == object.data["context"]
     end
   end
 
@@ -227,7 +232,6 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert is_nil(modified["object"]["like_count"])
       assert is_nil(modified["object"]["announcements"])
       assert is_nil(modified["object"]["announcement_count"])
-      assert is_nil(modified["object"]["context_id"])
       assert is_nil(modified["object"]["generator"])
     end
 
@@ -242,7 +246,6 @@ defmodule Pleroma.Web.ActivityPub.TransmogrifierTest do
       assert is_nil(modified["object"]["like_count"])
       assert is_nil(modified["object"]["announcements"])
       assert is_nil(modified["object"]["announcement_count"])
-      assert is_nil(modified["object"]["context_id"])
       assert is_nil(modified["object"]["likes"])
     end
 
diff --git a/test/pleroma/web/activity_pub/utils_test.exs b/test/pleroma/web/activity_pub/utils_test.exs
index 447621718..e42893849 100644
--- a/test/pleroma/web/activity_pub/utils_test.exs
+++ b/test/pleroma/web/activity_pub/utils_test.exs
@@ -429,7 +429,6 @@ defmodule Pleroma.Web.ActivityPub.UtilsTest do
       object = Object.normalize(note_activity, fetch: false)
       res = Utils.lazy_put_activity_defaults(%{"context" => object.data["id"]})
       assert res["context"] == object.data["id"]
-      assert res["context_id"] == object.id
       assert res["id"]
       assert res["published"]
     end
@@ -437,7 +436,6 @@ defmodule Pleroma.Web.ActivityPub.UtilsTest do
     test "returns map with fake id and published data" do
       assert %{
                "context" => "pleroma:fakecontext",
-               "context_id" => -1,
                "id" => "pleroma:fakeid",
                "published" => _
              } = Utils.lazy_put_activity_defaults(%{}, true)
@@ -454,13 +452,11 @@ defmodule Pleroma.Web.ActivityPub.UtilsTest do
         })
 
       assert res["context"] == object.data["id"]
-      assert res["context_id"] == object.id
       assert res["id"]
       assert res["published"]
       assert res["object"]["id"]
       assert res["object"]["published"]
       assert res["object"]["context"] == object.data["id"]
-      assert res["object"]["context_id"] == object.id
     end
   end
 
diff --git a/test/pleroma/web/common_api/utils_test.exs b/test/pleroma/web/common_api/utils_test.exs
index 5b2019969..b538c5979 100644
--- a/test/pleroma/web/common_api/utils_test.exs
+++ b/test/pleroma/web/common_api/utils_test.exs
@@ -4,7 +4,6 @@
 
 defmodule Pleroma.Web.CommonAPI.UtilsTest do
   alias Pleroma.Builders.UserBuilder
-  alias Pleroma.Object
   alias Pleroma.Web.CommonAPI
   alias Pleroma.Web.CommonAPI.ActivityDraft
   alias Pleroma.Web.CommonAPI.Utils
@@ -273,22 +272,6 @@ defmodule Pleroma.Web.CommonAPI.UtilsTest do
     end
   end
 
-  describe "context_to_conversation_id" do
-    test "creates a mapping object" do
-      conversation_id = Utils.context_to_conversation_id("random context")
-      object = Object.get_by_ap_id("random context")
-
-      assert conversation_id == object.id
-    end
-
-    test "returns an existing mapping for an existing object" do
-      {:ok, object} = Object.context_mapping("random context") |> Repo.insert()
-      conversation_id = Utils.context_to_conversation_id("random context")
-
-      assert conversation_id == object.id
-    end
-  end
-
   describe "formats date to asctime" do
     test "when date is in ISO 8601 format" do
       date = DateTime.utc_now() |> DateTime.to_iso8601()
@@ -517,17 +500,6 @@ defmodule Pleroma.Web.CommonAPI.UtilsTest do
     end
   end
 
-  describe "conversation_id_to_context/1" do
-    test "returns id" do
-      object = insert(:note)
-      assert Utils.conversation_id_to_context(object.id) == object.data["id"]
-    end
-
-    test "returns error if object not found" do
-      assert Utils.conversation_id_to_context("123") == {:error, "No such conversation"}
-    end
-  end
-
   describe "maybe_notify_mentioned_recipients/2" do
     test "returns recipients when activity is not `Create`" do
       activity = insert(:like_activity)
diff --git a/test/pleroma/web/mastodon_api/controllers/status_controller_test.exs b/test/pleroma/web/mastodon_api/controllers/status_controller_test.exs
index 0c9a47208..e23bddbff 100644
--- a/test/pleroma/web/mastodon_api/controllers/status_controller_test.exs
+++ b/test/pleroma/web/mastodon_api/controllers/status_controller_test.exs
@@ -262,6 +262,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusControllerTest do
         |> Map.put("url", nil)
         |> Map.put("uri", nil)
         |> Map.put("created_at", nil)
+        |> Kernel.put_in(["pleroma", "context"], nil)
         |> Kernel.put_in(["pleroma", "conversation_id"], nil)
 
       fake_conn =
@@ -285,6 +286,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusControllerTest do
         |> Map.put("url", nil)
         |> Map.put("uri", nil)
         |> Map.put("created_at", nil)
+        |> Kernel.put_in(["pleroma", "context"], nil)
         |> Kernel.put_in(["pleroma", "conversation_id"], nil)
 
       assert real_status == fake_status
diff --git a/test/pleroma/web/mastodon_api/views/status_view_test.exs b/test/pleroma/web/mastodon_api/views/status_view_test.exs
index 297889449..f76b115b7 100644
--- a/test/pleroma/web/mastodon_api/views/status_view_test.exs
+++ b/test/pleroma/web/mastodon_api/views/status_view_test.exs
@@ -14,10 +14,11 @@ defmodule Pleroma.Web.MastodonAPI.StatusViewTest do
   alias Pleroma.User
   alias Pleroma.UserRelationship
   alias Pleroma.Web.CommonAPI
-  alias Pleroma.Web.CommonAPI.Utils
   alias Pleroma.Web.MastodonAPI.AccountView
   alias Pleroma.Web.MastodonAPI.StatusView
 
+  require Bitwise
+
   import Pleroma.Factory
   import Tesla.Mock
   import OpenApiSpex.TestAssertions
@@ -226,7 +227,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusViewTest do
     object_data = Object.normalize(note, fetch: false).data
     user = User.get_cached_by_ap_id(note.data["actor"])
 
-    convo_id = Utils.context_to_conversation_id(object_data["context"])
+    convo_id = :erlang.crc32(object_data["context"]) |> Bitwise.band(Bitwise.bnot(0x8000_0000))
 
     status = StatusView.render("show.json", %{activity: note})
 
@@ -280,6 +281,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusViewTest do
       pleroma: %{
         local: true,
         conversation_id: convo_id,
+        context: object_data["context"],
         in_reply_to_account_acct: nil,
         content: %{"text/plain" => HTML.strip_tags(object_data["content"])},
         spoiler_text: %{"text/plain" => HTML.strip_tags(object_data["summary"])},
diff --git a/test/support/http_request_mock.ex b/test/support/http_request_mock.ex
index eb844e469..7f6065579 100644
--- a/test/support/http_request_mock.ex
+++ b/test/support/http_request_mock.ex
@@ -1084,6 +1084,14 @@ defmodule HttpRequestMock do
      }}
   end
 
+  def get("https://404.site" <> _, _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 404,
+       body: ""
+     }}
+  end
+
   def get(
         "https://zetsubou.xn--q9jyb4c/.well-known/webfinger?resource=acct:lain@zetsubou.xn--q9jyb4c",
         _,
@@ -1401,6 +1409,51 @@ defmodule HttpRequestMock do
      }}
   end
 
+  def get("https://mk.absturztau.be/users/8ozbzjs3o8", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/mametsuko@mk.absturztau.be.json"),
+       headers: activitypub_object_headers()
+     }}
+  end
+
+  def get("https://p.helene.moe/users/helene", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/helene@p.helene.moe.json"),
+       headers: activitypub_object_headers()
+     }}
+  end
+
+  def get("https://mk.absturztau.be/notes/93e7nm8wqg", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg.json"),
+       headers: activitypub_object_headers()
+     }}
+  end
+
+  def get("https://mk.absturztau.be/notes/93e7nm8wqg/activity", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/mk.absturztau.be-93e7nm8wqg-activity.json"),
+       headers: activitypub_object_headers()
+     }}
+  end
+
+  def get("https://p.helene.moe/objects/fd5910ac-d9dc-412e-8d1d-914b203296c4", _, _, _) do
+    {:ok,
+     %Tesla.Env{
+       status: 200,
+       body: File.read!("test/fixtures/tesla_mock/p.helene.moe-AM7S6vZQmL6pI9TgPY.json"),
+       headers: activitypub_object_headers()
+     }}
+  end
+
   def get(url, query, body, headers) do
     {:error,
      "Mock response not implemented for GET #{inspect(url)}, #{query}, #{inspect(body)}, #{inspect(headers)}"}