Decouple partial clone config

Previously partial clone configs is coupled with receive_max_input_size
check. This make sense when you think of partial clone as a replacement
for Git LFS but in truth, the 2 features are separated and should not be
 decoupled.

In self-managing instances, `receive_max_input_size` could be set to 0
while users could still wish to have partial clone feature enabled.

References:
- [Original discussion](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/16850#note_313323533)
- [Tracking issue](https://gitlab.com/gitlab-org/gitlab/-/issues/212926)

changelogs/unreleased/sluongngoc-decouple-partial-clone.yml

+---
+title: Decouple partial clone config from max input size
+merge_request: 30354
+author: Son Luong Ngoc
+type: changed

lib/api/internal/base.rb

@@ -69,13 +69,14 @@ module API
             }
 
             # Custom option for git-receive-pack command
+            if Feature.enabled?(:gitaly_upload_pack_filter, project, default_enabled: true)
+              payload[:git_config_options] << "uploadpack.allowFilter=true" << "uploadpack.allowAnySHA1InWant=true"
+            end
+
             receive_max_input_size = Gitlab::CurrentSettings.receive_max_input_size.to_i
+
             if receive_max_input_size > 0
               payload[:git_config_options] << "receive.maxInputSize=#{receive_max_input_size.megabytes}"
-
-              if Feature.enabled?(:gitaly_upload_pack_filter, project, default_enabled: true)
-                payload[:git_config_options] << "uploadpack.allowFilter=true" << "uploadpack.allowAnySHA1InWant=true"
-              end
             end
 
             response_with_status(**payload)

spec/requests/api/internal/base_spec.rb

@@ -441,10 +441,11 @@ describe API::Internal::Base do
             allow(Gitlab::CurrentSettings).to receive(:receive_max_input_size) { 1 }
           end
 
-          it 'returns custom git config' do
+          it 'returns maxInputSize and partial clone git config' do
             push(key, project)
 
             expect(json_response["git_config_options"]).to be_present
+            expect(json_response["git_config_options"]).to include("receive.maxInputSize=1048576")
             expect(json_response["git_config_options"]).to include("uploadpack.allowFilter=true")
             expect(json_response["git_config_options"]).to include("uploadpack.allowAnySHA1InWant=true")
           end
@@ -454,10 +455,11 @@ describe API::Internal::Base do
               stub_feature_flags(gitaly_upload_pack_filter: { enabled: false, thing: project })
             end
 
-            it 'does not include allowFilter and allowAnySha1InWant in the git config options' do
+            it 'returns only maxInputSize and not partial clone git config' do
               push(key, project)
 
               expect(json_response["git_config_options"]).to be_present
+              expect(json_response["git_config_options"]).to include("receive.maxInputSize=1048576")
               expect(json_response["git_config_options"]).not_to include("uploadpack.allowFilter=true")
               expect(json_response["git_config_options"]).not_to include("uploadpack.allowAnySHA1InWant=true")
             end
@@ -465,12 +467,28 @@ describe API::Internal::Base do
         end
 
         context 'when receive_max_input_size is empty' do
-          it 'returns an empty git config' do
+          before do
             allow(Gitlab::CurrentSettings).to receive(:receive_max_input_size) { nil }
+          end
 
+          it 'returns partial clone git config' do
             push(key, project)
 
-            expect(json_response["git_config_options"]).to be_empty
+            expect(json_response["git_config_options"]).to be_present
+            expect(json_response["git_config_options"]).to include("uploadpack.allowFilter=true")
+            expect(json_response["git_config_options"]).to include("uploadpack.allowAnySHA1InWant=true")
+          end
+
+          context 'when gitaly_upload_pack_filter feature flag is disabled' do
+            before do
+              stub_feature_flags(gitaly_upload_pack_filter: { enabled: false, thing: project })
+            end
+
+            it 'returns an empty git config' do
+              push(key, project)
+
+              expect(json_response["git_config_options"]).to be_empty
+            end
           end
         end
       end