Find namespace by env name instead of slug

The problem with using slugs is that we already have persisted
environments matching generic branch names but different slugs.
Environments are uniquely identified by by `(project_id, name)`, so this
should be just as safe.

See https://gitlab.com/gitlab-org/gitlab/issues/32341

app/finders/clusters/kubernetes_namespace_finder.rb

@@ -2,12 +2,12 @@
 
 module Clusters
   class KubernetesNamespaceFinder
-    attr_reader :cluster, :project, :environment_slug
+    attr_reader :cluster, :project, :environment_name
 
-    def initialize(cluster, project:, environment_slug:, allow_blank_token: false)
+    def initialize(cluster, project:, environment_name:, allow_blank_token: false)
       @cluster = cluster
       @project = project
-      @environment_slug = environment_slug
+      @environment_name = environment_name
       @allow_blank_token = allow_blank_token
     end
 
@@ -20,7 +20,11 @@ module Clusters
     attr_reader :allow_blank_token
 
     def find_namespace(with_environment:)
-      relation = with_environment ? namespaces.with_environment_slug(environment_slug) : namespaces
+      relation = if with_environment
+                   namespaces.with_environment_name(environment_name)
+                 else
+                   namespaces
+                 end
 
       relation.find_by_project_id(project.id)
     end

app/models/clusters/cluster.rb

@@ -172,7 +172,7 @@ module Clusters
       persisted_namespace = Clusters::KubernetesNamespaceFinder.new(
         self,
         project: project,
-        environment_slug: environment.slug
+        environment_name: environment.name
       ).execute
 
       persisted_namespace&.namespace || Gitlab::Kubernetes::DefaultNamespace.new(self, project: project).from_environment_slug(environment.slug)

app/models/clusters/kubernetes_namespace.rb

@@ -27,7 +27,7 @@ module Clusters
         algorithm: 'aes-256-cbc'
 
     scope :has_service_account_token, -> { where.not(encrypted_service_account_token: nil) }
-    scope :with_environment_slug, -> (slug) { joins(:environment).where(environments: { slug: slug }) }
+    scope :with_environment_name, -> (name) { joins(:environment).where(environments: { name: name }) }
 
     def token_name
       "#{namespace}-token"

app/models/clusters/platforms/kubernetes.rb

@@ -105,19 +105,11 @@ module Clusters
 
       private
 
-      ##
-      # Environment slug can be predicted given an environment
-      # name, so even if the environment isn't persisted yet we
-      # still know what to look for.
-      def environment_slug(name)
-        Gitlab::Slug::Environment.new(name).generate
-      end
-
       def find_persisted_namespace(project, environment_name:)
         Clusters::KubernetesNamespaceFinder.new(
           cluster,
           project: project,
-          environment_slug: environment_slug(environment_name)
+          environment_name: environment_name
         ).execute
       end
 

lib/gitlab/ci/build/prerequisite/kubernetes_namespace.rb

@@ -36,7 +36,7 @@ module Gitlab
               Clusters::KubernetesNamespaceFinder.new(
                 deployment_cluster,
                 project: environment.project,
-                environment_slug: environment.slug,
+                environment_name: environment.name,
                 allow_blank_token: true
               ).execute
             end

spec/finders/clusters/kubernetes_namespace_finder_spec.rb

@@ -7,7 +7,7 @@ RSpec.describe Clusters::KubernetesNamespaceFinder do
     described_class.new(
       cluster,
       project: project,
-      environment_slug: 'production',
+      environment_name: 'production',
       allow_blank_token: allow_blank_token
     )
   end
@@ -22,8 +22,8 @@ RSpec.describe Clusters::KubernetesNamespaceFinder do
   end
 
   describe '#execute' do
-    let(:production) { create(:environment, project: project, slug: 'production') }
-    let(:staging) { create(:environment, project: project, slug: 'staging') }
+    let(:production) { create(:environment, project: project, name: 'production') }
+    let(:staging) { create(:environment, project: project, name: 'staging') }
 
     let(:cluster) { create(:cluster, :group, :provided_by_user) }
     let(:project) { create(:project) }

spec/models/clusters/cluster_spec.rb

@@ -546,7 +546,7 @@ describe Clusters::Cluster, :use_clean_rails_memory_store_caching do
 
     before do
       expect(Clusters::KubernetesNamespaceFinder).to receive(:new)
-        .with(cluster, project: environment.project, environment_slug: environment.slug)
+        .with(cluster, project: environment.project, environment_name: environment.name)
         .and_return(double(execute: persisted_namespace))
     end
 

spec/models/clusters/kubernetes_namespace_spec.rb

@@ -24,13 +24,13 @@ RSpec.describe Clusters::KubernetesNamespace, type: :model do
     end
   end
 
-  describe '.with_environment_slug' do
+  describe '.with_environment_name' do
     let(:cluster) { create(:cluster, :group) }
-    let(:environment) { create(:environment, slug: slug) }
+    let(:environment) { create(:environment, name: name) }
 
-    let(:slug) { 'production' }
+    let(:name) { 'production' }
 
-    subject { described_class.with_environment_slug(slug) }
+    subject { described_class.with_environment_name(name) }
 
     context 'there is no associated environment' do
       let!(:namespace) { create(:cluster_kubernetes_namespace, cluster: cluster, project: environment.project) }
@@ -48,12 +48,12 @@ RSpec.describe Clusters::KubernetesNamespace, type: :model do
         )
       end
 
-      context 'with a matching slug' do
+      context 'with a matching name' do
         it { is_expected.to eq [namespace] }
       end
 
-      context 'without a matching slug' do
-        let(:environment) { create(:environment, slug: 'staging') }
+      context 'without a matching name' do
+        let(:environment) { create(:environment, name: 'staging') }
 
         it { is_expected.to be_empty }
       end

spec/models/clusters/platforms/kubernetes_spec.rb

@@ -218,7 +218,7 @@ describe Clusters::Platforms::Kubernetes do
 
     before do
       allow(Clusters::KubernetesNamespaceFinder).to receive(:new)
-        .with(cluster, project: project, environment_slug: environment_slug)
+        .with(cluster, project: project, environment_name: environment_name)
         .and_return(double(execute: persisted_namespace))
     end