Improve error message for project not found

changelogs/unreleased/326839-improve-message.yml

+---
+title: Improve message for :project_not_found error to indicate possible cause
+merge_request: 58945
+author: Ignacy Moryc @ignacy
+type: changed

ee/spec/requests/git_http_geo_spec.rb

@@ -534,7 +534,7 @@ RSpec.describe "Git HTTP requests (Geo)", :geo do
 
               it 'returns a 404' do
                 is_expected.to have_gitlab_http_status(:not_found)
-                expect(response.body).to eql('The project you were looking for could not be found.')
+                expect(response.body).to eql("The project you were looking for could not be found or you don't have permission to view it.")
               end
             end
 

lib/gitlab/git_access.rb

@@ -22,7 +22,7 @@ module Gitlab
       auth_download: 'You are not allowed to download code.',
       deploy_key_upload: 'This deploy key does not have write access to this project.',
       no_repo: 'A repository for this project does not exist yet.',
-      project_not_found: 'The project you were looking for could not be found.',
+      project_not_found: "The project you were looking for could not be found or you don't have permission to view it.",
       command_not_allowed: "The command you're trying to execute is not allowed.",
       upload_pack_disabled_over_http: 'Pulling over HTTP is not allowed.',
       receive_pack_disabled_over_http: 'Pushing over HTTP is not allowed.',

spec/lib/gitlab/git_access_spec.rb

@@ -554,19 +554,19 @@ RSpec.describe Gitlab::GitAccess do
             context 'when the repository is public' do
               let(:options) { %i[repository_enabled] }
 
-              it { expect { pull_access_check }.to raise_error('The project you were looking for could not be found.') }
+              it { expect { pull_access_check }.to raise_error("The project you were looking for could not be found or you don't have permission to view it.") }
             end
 
             context 'when the repository is private' do
               let(:options) { %i[repository_private] }
 
-              it { expect { pull_access_check }.to raise_error('The project you were looking for could not be found.') }
+              it { expect { pull_access_check }.to raise_error("The project you were looking for could not be found or you don't have permission to view it.") }
             end
 
             context 'when the repository is disabled' do
               let(:options) { %i[repository_disabled] }
 
-              it { expect { pull_access_check }.to raise_error('The project you were looking for could not be found.') }
+              it { expect { pull_access_check }.to raise_error("The project you were looking for could not be found or you don't have permission to view it.") }
             end
           end
         end
@@ -596,13 +596,13 @@ RSpec.describe Gitlab::GitAccess do
             context 'when the repository is private' do
               let(:options) { %i[repository_private] }
 
-              it { expect { pull_access_check }.to raise_error('The project you were looking for could not be found.') }
+              it { expect { pull_access_check }.to raise_error("The project you were looking for could not be found or you don't have permission to view it.") }
             end
 
             context 'when the repository is disabled' do
               let(:options) { %i[repository_disabled] }
 
-              it { expect { pull_access_check }.to raise_error('The project you were looking for could not be found.') }
+              it { expect { pull_access_check }.to raise_error("The project you were looking for could not be found or you don't have permission to view it.") }
             end
           end
         end