Fix provider server URL used when listing repos to import

Also use Gitlab::Auth::OAuth::Provider.config_for to access OmniAuth config

app/helpers/import_helper.rb

 module ImportHelper
+  include ::Gitlab::Utils::StrongMemoize
+
   def has_ci_cd_only_params?
     false
   end
@@ -75,17 +77,18 @@ module ImportHelper
   private
 
   def github_project_url(full_path)
-    "#{github_root_url}/#{full_path}"
+    URI.join(github_root_url, full_path).to_s
   end
 
   def github_root_url
-    return @github_url if defined?(@github_url)
+    strong_memoize(:github_url) do
+      provider = Gitlab::Auth::OAuth::Provider.config_for('github')
 
-    provider = Gitlab.config.omniauth.providers.find { |p| p.name == 'github' }
-    @github_url = provider.fetch('url', 'https://github.com') if provider
+      provider&.dig('url').presence || 'https://github.com'
+    end
   end
 
   def gitea_project_url(full_path)
-    "#{@gitea_host_url.sub(%r{/+\z}, '')}/#{full_path}"
+    URI.join(@gitea_host_url, full_path).to_s
   end
 end

changelogs/unreleased/34604-fix-generated-url-for-external-repository.yml

+---
+title: Fix generated URL when listing repoitories for import
+merge_request: 17692
+author:
+type: fixed

lib/gitlab/auth/saml/config.rb

@@ -4,7 +4,7 @@ module Gitlab
       class Config
         class << self
           def options
-            Gitlab.config.omniauth.providers.find { |provider| provider.name == 'saml' }
+            Gitlab::Auth::OAuth::Provider.config_for('saml')
           end
 
           def groups

lib/gitlab/github_import/client.rb

@@ -197,10 +197,7 @@ module Gitlab
       end
 
       def github_omniauth_provider
-        @github_omniauth_provider ||=
-          Gitlab.config.omniauth.providers
-                .find { |provider| provider.name == 'github' }
-                .to_h
+        @github_omniauth_provider ||= Gitlab::Auth::OAuth::Provider.config_for('github').to_h
       end
 
       def rate_limit_counter

lib/gitlab/gitlab_import/client.rb

@@ -72,7 +72,7 @@ module Gitlab
       end
 
       def config
-        Gitlab.config.omniauth.providers.find {|provider| provider.name == "gitlab"}
+        Gitlab::Auth::OAuth::Provider.config_for('gitlab')
       end
 
       def gitlab_options

lib/gitlab/legacy_github_import/client.rb

@@ -83,7 +83,7 @@ module Gitlab
       end
 
       def config
-        Gitlab.config.omniauth.providers.find { |provider| provider.name == "github" }
+        Gitlab::Auth::OAuth::Provider.config_for('github')
       end
 
       def github_options

lib/google_api/auth.rb

@@ -32,7 +32,7 @@ module GoogleApi
     private
 
     def config
-      Gitlab.config.omniauth.providers.find { |provider| provider.name == "google_oauth2" }
+      Gitlab::Auth::OAuth::Provider.config_for('google_oauth2')
     end
 
     def client

spec/helpers/import_helper_spec.rb

@@ -27,25 +27,48 @@ describe ImportHelper do
 
   describe '#provider_project_link' do
     context 'when provider is "github"' do
+      let(:github_server_url) { nil }
+
+      before do
+        setting = Settingslogic.new('name' => 'github')
+        setting['url'] = github_server_url if github_server_url
+
+        allow(Gitlab.config.omniauth).to receive(:providers).and_return([setting])
+      end
+
       context 'when provider does not specify a custom URL' do
         it 'uses default GitHub URL' do
-          allow(Gitlab.config.omniauth).to receive(:providers)
-          .and_return([Settingslogic.new('name' => 'github')])
-
           expect(helper.provider_project_link('github', 'octocat/Hello-World'))
           .to include('href="https://github.com/octocat/Hello-World"')
         end
       end
 
       context 'when provider specify a custom URL' do
+        let(:github_server_url) { 'https://github.company.com' }
+
         it 'uses custom URL' do
-          allow(Gitlab.config.omniauth).to receive(:providers)
-          .and_return([Settingslogic.new('name' => 'github', 'url' => 'https://github.company.com')])
+          expect(helper.provider_project_link('github', 'octocat/Hello-World'))
+          .to include('href="https://github.company.com/octocat/Hello-World"')
+        end
+      end
+
+      context "when custom URL contains a '/' char at the end" do
+        let(:github_server_url) { 'https://github.company.com/' }
 
+        it "doesn't render double slash" do
           expect(helper.provider_project_link('github', 'octocat/Hello-World'))
           .to include('href="https://github.company.com/octocat/Hello-World"')
         end
       end
+
+      context 'when provider is missing' do
+        it 'uses the default URL' do
+          allow(Gitlab.config.omniauth).to receive(:providers).and_return([])
+
+          expect(helper.provider_project_link('github', 'octocat/Hello-World'))
+          .to include('href="https://github.com/octocat/Hello-World"')
+        end
+      end
     end
 
     context 'when provider is "gitea"' do