Reset templates cache key

Change method name for fetching issue and merge request templates
which also resets the caching key. Also do not cache empty hash
on fallback but rather default to nil, which would make another
gitally request and cache a success value or be nil in case of failure

app/models/repository.rb

@@ -43,7 +43,7 @@ class Repository
                       changelog license_blob license_key gitignore
                       gitlab_ci_yml branch_names tag_names branch_count
                       tag_count avatar exists? root_ref merged_branch_names
-                      has_visible_content? issue_template_names_by_category merge_request_template_names_by_category
+                      has_visible_content? issue_template_names_hash merge_request_template_names_hash
                       user_defined_metrics_dashboard_paths xcode_project? has_ambiguous_refs?).freeze
 
   # Methods that use cache_method but only memoize the value
@@ -60,8 +60,8 @@ class Repository
     gitignore: :gitignore,
     gitlab_ci: :gitlab_ci_yml,
     avatar: :avatar,
-    issue_template: :issue_template_names_by_category,
-    merge_request_template: :merge_request_template_names_by_category,
+    issue_template: :issue_template_names_hash,
+    merge_request_template: :merge_request_template_names_hash,
     metrics_dashboard: :user_defined_metrics_dashboard_paths,
     xcode_config: :xcode_project?
   }.freeze
@@ -573,15 +573,15 @@ class Repository
   cache_method :avatar
 
   # store issue_template_names as hash
-  def issue_template_names_by_category
+  def issue_template_names_hash
     Gitlab::Template::IssueTemplate.repository_template_names(project)
   end
-  cache_method :issue_template_names_by_category, fallback: {}
+  cache_method :issue_template_names_hash, fallback: {}
 
-  def merge_request_template_names_by_category
+  def merge_request_template_names_hash
     Gitlab::Template::MergeRequestTemplate.repository_template_names(project)
   end
-  cache_method :merge_request_template_names_by_category, fallback: {}
+  cache_method :merge_request_template_names_hash, fallback: {}
 
   def user_defined_metrics_dashboard_paths
     Gitlab::Metrics::Dashboard::RepoDashboardFinder.list_dashboards(project)

changelogs/unreleased/reset_template_cache_key.yml

+---
+title: Reset description template names cache key to reload an updated templates structure
+merge_request: 54614
+author:
+type: fixed

lib/gitlab/template/base_template.rb

@@ -108,7 +108,7 @@ module Gitlab
         # Gitaly the actual template names within a given project's repository for all file templates
         # other than `issue` and `merge request` description templates, which would instead
         # overwrite the `template_names` method to return a redis cached version, by reading cached values
-        # from `repository.issue_template_names_by_category` and `repository.merge_request_template_names_by_category`
+        # from `repository.issue_template_names_hash` and `repository.merge_request_template_names_hash`
         # methods.
         def repository_template_names(project)
           template_names_by_category(self.all(project))

lib/gitlab/template/issue_template.rb

@@ -23,7 +23,7 @@ module Gitlab
           # own caching mechanism to avoid the back and forth call jumps between finder and model.
           #
           # follow-up issue: https://gitlab.com/gitlab-org/gitlab/-/issues/300279
-          project.repository.issue_template_names_by_category
+          project.repository.issue_template_names_hash
         end
 
         def by_category(category, project = nil, empty_category_title: nil)

lib/gitlab/template/merge_request_template.rb

@@ -23,7 +23,7 @@ module Gitlab
           # own caching mechanism to avoid the back and forth call jumps between finder and model.
           #
           # follow-up issue: https://gitlab.com/gitlab-org/gitlab/-/issues/300279
-          project.repository.merge_request_template_names_by_category
+          project.repository.merge_request_template_names_hash
         end
 
         def by_category(category, project = nil, empty_category_title: nil)

spec/models/repository_spec.rb

@@ -1949,8 +1949,8 @@ RSpec.describe Repository do
         :root_ref,
         :merged_branch_names,
         :has_visible_content?,
-        :issue_template_names_by_category,
-        :merge_request_template_names_by_category,
+        :issue_template_names_hash,
+        :merge_request_template_names_hash,
         :user_defined_metrics_dashboard_paths,
         :xcode_project?,
         :has_ambiguous_refs?