hook: Introduce `ProcReceiveHandler` and `ProcReceiveRegistry`

Introduce the `ProcReceiveHandler` which provides the mechanism for RPCs
which invoked git-receive-pack(1) to interact with the proc-receive
hook. It provides access to a list of references that a transaction is
attempting to update, and functions to accept or reject individual
updates.

Also, introduce `ProcReceiveRegistry`, a registry which provides the
proc-receive handlers against a provided transaction ID. The registry
allows RPCs which perform commands that execute git-receive-pack(1) to
hook into the proc-receive handler. The RPC must register itself with
the registry by calling RegisterWaiter(), this provides a channel where
the handler will be provided along with a registry cleanup function.

1 files changed, 12 insertions, 3 deletions

diff --git a/internal/gitaly/hook/prereceive_test.go b/internal/gitaly/hook/prereceive_test.go
index 77f6bb4a1..1bfab9447 100644
--- a/internal/gitaly/hook/prereceive_test.go
+++ b/internal/gitaly/hook/prereceive_test.go
@@ -43,7 +43,7 @@ func TestPrereceive_customHooks(t *testing.T) {
 	txManager := transaction.NewTrackingManager()
 	hookManager := NewManager(cfg, locator, testhelper.SharedLogger(t), gitCmdFactory, txManager, gitlab.NewMockClient(
 		t, gitlab.MockAllowed, gitlab.MockPreReceive, gitlab.MockPostReceive,
-	), NewTransactionRegistry(storagemgr.NewTransactionRegistry()))
+	), NewTransactionRegistry(storagemgr.NewTransactionRegistry()), NewProcReceiveRegistry())
 
 	receiveHooksPayload := &git.UserDetails{
 		UserID:   "1234",
@@ -228,7 +228,7 @@ func TestPrereceive_quarantine(t *testing.T) {
 
 	hookManager := NewManager(cfg, config.NewLocator(cfg), testhelper.SharedLogger(t), gittest.NewCommandFactory(t, cfg), nil, gitlab.NewMockClient(
 		t, gitlab.MockAllowed, gitlab.MockPreReceive, gitlab.MockPostReceive,
-	), NewTransactionRegistry(storagemgr.NewTransactionRegistry()))
+	), NewTransactionRegistry(storagemgr.NewTransactionRegistry()), NewProcReceiveRegistry())
 
 	//nolint:gitaly-linters
 	gittest.WriteCustomHook(t, repoPath, "pre-receive", []byte(fmt.Sprintf(
@@ -419,7 +419,16 @@ func TestPrereceive_gitlab(t *testing.T) {
 				},
 			}
 
-			hookManager := NewManager(cfg, config.NewLocator(cfg), testhelper.SharedLogger(t), gittest.NewCommandFactory(t, cfg), transaction.NewManager(cfg, testhelper.SharedLogger(t), backchannel.NewRegistry()), &gitlabAPI, NewTransactionRegistry(storagemgr.NewTransactionRegistry()))
+			hookManager := NewManager(
+				cfg,
+				config.NewLocator(cfg),
+				testhelper.SharedLogger(t),
+				gittest.NewCommandFactory(t, cfg),
+				transaction.NewManager(cfg, testhelper.SharedLogger(t), backchannel.NewRegistry()),
+				&gitlabAPI,
+				NewTransactionRegistry(storagemgr.NewTransactionRegistry()),
+				NewProcReceiveRegistry(),
+			)
 
 			gittest.WriteCustomHook(t, repoPath, "pre-receive", []byte("#!/bin/sh\necho called\n"))