From deffa0dfd24f1fb90b03e10432ef575954c78615 Mon Sep 17 00:00:00 2001
From: jorg-vr <jorg.vr@live.be>
Date: Wed, 1 Feb 2023 11:01:27 +0100
Subject: [PATCH 1/3] Keep programming languages in memory

---
 app/models/exercise.rb             |  4 ++++
 app/models/programming_language.rb | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/app/models/exercise.rb b/app/models/exercise.rb
index e07d2cde8a..5bc993effe 100644
--- a/app/models/exercise.rb
+++ b/app/models/exercise.rb
@@ -43,6 +43,10 @@ class Exercise < Activity
   # Only used manually from the console
   scope :unstarted_by, ->(users) { where.not(id: Submission.where(user_id: users).select(:exercise_id)) }
 
+  def programming_language
+    ProgrammingLanguage.find(programming_language_id) || super
+  end
+
   def exercise?
     true
   end
diff --git a/app/models/programming_language.rb b/app/models/programming_language.rb
index 3057ee7c34..e42bedb125 100644
--- a/app/models/programming_language.rb
+++ b/app/models/programming_language.rb
@@ -16,9 +16,29 @@ class ProgrammingLanguage < ApplicationRecord
   DEFAULT_ICON = 'file-document-edit-outline'.freeze
 
   before_save :fill_fields
+  after_save :remove_from_cache
 
   has_many :exercises, dependent: :restrict_with_error
 
+  # There are only a few programming languages, so we can keep them in memory
+  @@in_memory_instances = {}
+
+  def self.find(*ids)
+    # We don't have cache keys for this stuff yet
+    return super unless ids.length == 1
+
+    id = ids.first
+    return nil if id.nil?
+
+    return super unless id.is_a?(Integer)
+
+    @@in_memory_instances[id] ||= super
+  end
+
+  def remove_from_cache
+    @@in_memory_instances.delete(id)
+  end
+
   def fill_fields
     self.editor_name ||= name
     self.renderer_name ||= name

From 459dd8f09222c14ef902bcaced3b6c4d05934c8d Mon Sep 17 00:00:00 2001
From: jorg-vr <jorg.vr@live.be>
Date: Wed, 1 Feb 2023 11:18:39 +0100
Subject: [PATCH 2/3] Ignore linting

---
 app/models/programming_language.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/models/programming_language.rb b/app/models/programming_language.rb
index e42bedb125..a457a2f557 100644
--- a/app/models/programming_language.rb
+++ b/app/models/programming_language.rb
@@ -21,7 +21,7 @@ class ProgrammingLanguage < ApplicationRecord
   has_many :exercises, dependent: :restrict_with_error
 
   # There are only a few programming languages, so we can keep them in memory
-  @@in_memory_instances = {}
+  @@in_memory_instances = {} # rubocop:disable Style/ClassVars
 
   def self.find(*ids)
     # We don't have cache keys for this stuff yet

From 22789b124e605c0030edf7587488466438539664 Mon Sep 17 00:00:00 2001
From: jorg-vr <jorg.vr@live.be>
Date: Wed, 1 Feb 2023 11:46:10 +0100
Subject: [PATCH 3/3] Don't overwrite find

---
 app/models/exercise.rb             |  2 +-
 app/models/programming_language.rb | 10 +++-------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/app/models/exercise.rb b/app/models/exercise.rb
index 5bc993effe..a5ad8acb1c 100644
--- a/app/models/exercise.rb
+++ b/app/models/exercise.rb
@@ -44,7 +44,7 @@ class Exercise < Activity
   scope :unstarted_by, ->(users) { where.not(id: Submission.where(user_id: users).select(:exercise_id)) }
 
   def programming_language
-    ProgrammingLanguage.find(programming_language_id) || super
+    ProgrammingLanguage.cached_find(programming_language_id) || super
   end
 
   def exercise?
diff --git a/app/models/programming_language.rb b/app/models/programming_language.rb
index a457a2f557..de8be4017c 100644
--- a/app/models/programming_language.rb
+++ b/app/models/programming_language.rb
@@ -23,16 +23,12 @@ class ProgrammingLanguage < ApplicationRecord
   # There are only a few programming languages, so we can keep them in memory
   @@in_memory_instances = {} # rubocop:disable Style/ClassVars
 
-  def self.find(*ids)
-    # We don't have cache keys for this stuff yet
-    return super unless ids.length == 1
-
-    id = ids.first
+  def self.cached_find(id)
     return nil if id.nil?
 
-    return super unless id.is_a?(Integer)
+    return nil unless id.is_a?(Integer)
 
-    @@in_memory_instances[id] ||= super
+    @@in_memory_instances[id] ||= find(id)
   end
 
   def remove_from_cache