Revert "Merge branch 'sh-fix-cpp-templates-404' into 'master'"

This reverts commit 4b282e9c, reversing
changes made to b6f37434.

changelogs/unreleased/sh-fix-cpp-templates-404.yml

----
-title: Fix 404s when C++ .gitignore template selected
-merge_request: 25416
-author:
-type: fixed

lib/api/project_templates.rb

@@ -36,10 +36,7 @@ module API
         optional :project, type: String, desc: 'The project name to use when expanding placeholders in the template. Only affects licenses'
         optional :fullname, type: String, desc: 'The full name of the copyright holder to use when expanding placeholders in the template. Only affects licenses'
       end
-      # The regex is needed to ensure a period (e.g. agpl-3.0)
-      # isn't confused with a format type. We also need to allow encoded
-      # values (e.g. C%2B%2B for C++), so allow % and + as well.
-      get ':id/templates/:type/:name', requirements: { name: /[\w%.+-]+/ } do
+      get ':id/templates/:type/:name', requirements: { name: /[\w\.-]+/ } do
         template = TemplateFinder
           .build(params[:type], user_project, name: params[:name])
           .execute

spec/requests/api/project_templates_spec.rb

@@ -92,22 +92,6 @@ describe API::ProjectTemplates do
       expect(json_response['name']).to eq('Actionscript')
     end
 
-    it 'returns C++ gitignore' do
-      get api("/projects/#{public_project.id}/templates/gitignores/C++")
-
-      expect(response).to have_gitlab_http_status(200)
-      expect(response).to match_response_schema('public_api/v4/template')
-      expect(json_response['name']).to eq('C++')
-    end
-
-    it 'returns C++ gitignore for URL-encoded names' do
-      get api("/projects/#{public_project.id}/templates/gitignores/C%2B%2B")
-
-      expect(response).to have_gitlab_http_status(200)
-      expect(response).to match_response_schema('public_api/v4/template')
-      expect(json_response['name']).to eq('C++')
-    end
-
     it 'returns a specific gitlab_ci_yml' do
       get api("/projects/#{public_project.id}/templates/gitlab_ci_ymls/Android")
 
@@ -141,18 +125,6 @@ describe API::ProjectTemplates do
       expect(response).to have_gitlab_http_status(200)
       expect(response).to match_response_schema('public_api/v4/license')
     end
-
-    shared_examples 'path traversal attempt' do |template_type|
-      it 'rejects invalid filenames' do
-        get api("/projects/#{public_project.id}/templates/#{template_type}/%2e%2e%2fPython%2ea")
-
-        expect(response).to have_gitlab_http_status(500)
-      end
-    end
-
-    TemplateFinder::VENDORED_TEMPLATES.each do |template_type, _|
-      it_behaves_like 'path traversal attempt', template_type
-    end
   end
 
   describe 'GET /projects/:id/templates/licenses/:key' do