From d6ce1bc7628fac04ac0b0989a930cc471e45955b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marko=20Ga=C4=87e=C5=A1a?= <marko.gacesa@harness.io>
Date: Fri, 20 Jan 2023 17:06:35 +0100
Subject: [PATCH] Added gitrpc.UpdateRef (#236)

---
 gitrpc/common.go                              |   2 +
 gitrpc/enum/ref.go                            |  51 ++
 gitrpc/interface.go                           |   8 +-
 gitrpc/internal/gitea/ref.go                  |  65 ++-
 gitrpc/internal/service/interface.go          |   4 +-
 gitrpc/internal/service/ref.go                |  44 +-
 gitrpc/internal/types/types.go                |   7 -
 gitrpc/proto/ref.proto                        |  24 +-
 gitrpc/ref.go                                 |  64 +--
 gitrpc/rpc/ref.pb.go                          | 440 ++++++++++++------
 gitrpc/rpc/ref_grpc.pb.go                     |  36 ++
 internal/api/controller/pullreq/controller.go |  21 +-
 internal/api/controller/pullreq/pr_create.go  |  13 +-
 .../api/controller/pullreq/review_submit.go   |   7 +-
 14 files changed, 574 insertions(+), 212 deletions(-)
 create mode 100644 gitrpc/enum/ref.go

diff --git a/gitrpc/common.go b/gitrpc/common.go
index ab94a8dc2..058cdbbf4 100644
--- a/gitrpc/common.go
+++ b/gitrpc/common.go
@@ -6,6 +6,8 @@ package gitrpc
 
 import "github.com/harness/gitness/gitrpc/rpc"
 
+const NilSHA = "0000000000000000000000000000000000000000"
+
 // ReadParams contains the base parameters for read operations.
 type ReadParams struct {
 	RepoUID string
diff --git a/gitrpc/enum/ref.go b/gitrpc/enum/ref.go
new file mode 100644
index 000000000..94de6c332
--- /dev/null
+++ b/gitrpc/enum/ref.go
@@ -0,0 +1,51 @@
+// Copyright 2022 Harness Inc. All rights reserved.
+// Use of this source code is governed by the Polyform Free Trial License
+// that can be found in the LICENSE.md file for this repository.
+
+package enum
+
+import "github.com/harness/gitness/gitrpc/rpc"
+
+type RefType int
+
+const (
+	RefTypeRaw RefType = iota
+	RefTypeBranch
+	RefTypeTag
+	RefTypePullReqHead
+	RefTypePullReqMerge
+)
+
+func RefFromRPC(t rpc.RefType) (RefType, bool) {
+	switch t {
+	case rpc.RefType_RefRaw:
+		return RefTypeRaw, true
+	case rpc.RefType_RefBranch:
+		return RefTypeBranch, true
+	case rpc.RefType_RefTag:
+		return RefTypeTag, true
+	case rpc.RefType_RefPullReqHead:
+		return RefTypePullReqHead, true
+	case rpc.RefType_RefPullReqMerge:
+		return RefTypePullReqMerge, true
+	default:
+		return 0, false
+	}
+}
+
+func RefToRPC(t RefType) (rpc.RefType, bool) {
+	switch t {
+	case RefTypeRaw:
+		return rpc.RefType_RefRaw, true
+	case RefTypeBranch:
+		return rpc.RefType_RefBranch, true
+	case RefTypeTag:
+		return rpc.RefType_RefTag, true
+	case RefTypePullReqHead:
+		return rpc.RefType_RefPullReqHead, true
+	case RefTypePullReqMerge:
+		return rpc.RefType_RefPullReqMerge, true
+	default:
+		return 0, false
+	}
+}
diff --git a/gitrpc/interface.go b/gitrpc/interface.go
index eb3a469df..144806675 100644
--- a/gitrpc/interface.go
+++ b/gitrpc/interface.go
@@ -18,7 +18,13 @@ type Interface interface {
 	CreateBranch(ctx context.Context, params *CreateBranchParams) (*CreateBranchOutput, error)
 	DeleteBranch(ctx context.Context, params *DeleteBranchParams) error
 	ListBranches(ctx context.Context, params *ListBranchesParams) (*ListBranchesOutput, error)
-	GetRef(ctx context.Context, params *GetRefParams) (*GetRefResponse, error)
+
+	GetRef(ctx context.Context, params GetRefParams) (GetRefResponse, error)
+
+	// UpdateRef creates, updates or deletes a git ref. If the OldValue is defined it must match the reference value
+	// prior to the call. To remove a ref use the zero ref as the NewValue. To require the creation of a new one and
+	// not update of an exiting one, set the zero ref as the OldValue.
+	UpdateRef(ctx context.Context, params UpdateRefParams) error
 
 	/*
 	 * Commits service
diff --git a/gitrpc/internal/gitea/ref.go b/gitrpc/internal/gitea/ref.go
index 6be9ff4b4..a450b7620 100644
--- a/gitrpc/internal/gitea/ref.go
+++ b/gitrpc/internal/gitea/ref.go
@@ -11,6 +11,7 @@ import (
 	"math"
 	"strings"
 
+	"github.com/harness/gitness/gitrpc/enum"
 	"github.com/harness/gitness/gitrpc/internal/types"
 
 	gitea "code.gitea.io/gitea/modules/git"
@@ -126,14 +127,10 @@ func walkGiteaReferenceParser(parser *gitearef.Parser, handler types.WalkReferen
 	return nil
 }
 
-func (g Adapter) GetRef(ctx context.Context, repoPath, refName string, refType types.RefType) (string, error) {
-	switch refType {
-	case types.RefTypeBranch:
-		refName = gitea.BranchPrefix + refName
-	case types.RefTypeTag:
-		refName = gitea.TagPrefix + refName
-	default:
-		return "", types.ErrInvalidArgument
+func (g Adapter) GetRef(ctx context.Context, repoPath, refName string, refType enum.RefType) (string, error) {
+	refName, errRef := getRef(refName, refType)
+	if errRef != nil {
+		return "", errRef
 	}
 
 	cmd := gitea.NewCommand(ctx, "show-ref", "--verify", "-s", "--", refName)
@@ -149,3 +146,55 @@ func (g Adapter) GetRef(ctx context.Context, repoPath, refName string, refType t
 
 	return strings.TrimSpace(stdout), nil
 }
+
+func (g Adapter) UpdateRef(ctx context.Context,
+	repoPath, refName string, refType enum.RefType,
+	newValue, oldValue string,
+) error {
+	refName, errRef := getRef(refName, refType)
+	if errRef != nil {
+		return errRef
+	}
+
+	args := make([]string, 0, 4)
+	args = append(args, "update-ref", refName, newValue)
+	if oldValue != "" {
+		args = append(args, oldValue)
+	}
+
+	cmd := gitea.NewCommand(ctx, args...)
+	_, _, err := cmd.RunStdString(&gitea.RunOpts{
+		Dir: repoPath,
+	})
+	if err != nil {
+		if err.IsExitCode(128) {
+			return types.ErrNotFound
+		}
+		return err
+	}
+
+	return nil
+}
+
+func getRef(refName string, refType enum.RefType) (string, error) {
+	const (
+		refPullReqPrefix      = "refs/pullreq/"
+		refPullReqHeadSuffix  = "/head"
+		refPullReqMergeSuffix = "/merge"
+	)
+
+	switch refType {
+	case enum.RefTypeRaw:
+		return refName, nil
+	case enum.RefTypeBranch:
+		return gitea.BranchPrefix + refName, nil
+	case enum.RefTypeTag:
+		return gitea.TagPrefix + refName, nil
+	case enum.RefTypePullReqHead:
+		return refPullReqPrefix + refName + refPullReqHeadSuffix, nil
+	case enum.RefTypePullReqMerge:
+		return refPullReqPrefix + refName + refPullReqMergeSuffix, nil
+	default:
+		return "", types.ErrInvalidArgument
+	}
+}
diff --git a/gitrpc/internal/service/interface.go b/gitrpc/internal/service/interface.go
index fd93fa6d1..9c0b3e60c 100644
--- a/gitrpc/internal/service/interface.go
+++ b/gitrpc/internal/service/interface.go
@@ -8,6 +8,7 @@ import (
 	"context"
 	"io"
 
+	"github.com/harness/gitness/gitrpc/enum"
 	"github.com/harness/gitness/gitrpc/internal/types"
 )
 
@@ -39,7 +40,8 @@ type GitAdapter interface {
 	GetBranch(ctx context.Context, repoPath string, branchName string) (*types.Branch, error)
 	GetCommitDivergences(ctx context.Context, repoPath string,
 		requests []types.CommitDivergenceRequest, max int32) ([]types.CommitDivergence, error)
-	GetRef(ctx context.Context, repoPath string, name string, refType types.RefType) (string, error)
+	GetRef(ctx context.Context, repoPath string, name string, refType enum.RefType) (string, error)
+	UpdateRef(ctx context.Context, repoPath, refName string, refType enum.RefType, newValue, oldValue string) error
 	CreateTemporaryRepoForPR(ctx context.Context, reposTempPath string, pr *types.PullRequest) (string, error)
 	Merge(ctx context.Context, pr *types.PullRequest, mergeMethod string, trackingBranch string,
 		tmpBasePath string, mergeMsg string, env []string) error
diff --git a/gitrpc/internal/service/ref.go b/gitrpc/internal/service/ref.go
index c9949d433..b149942f9 100644
--- a/gitrpc/internal/service/ref.go
+++ b/gitrpc/internal/service/ref.go
@@ -10,6 +10,7 @@ import (
 	"math"
 	"strings"
 
+	"github.com/harness/gitness/gitrpc/enum"
 	"github.com/harness/gitness/gitrpc/internal/types"
 	"github.com/harness/gitness/gitrpc/rpc"
 
@@ -178,24 +179,19 @@ func wrapInstructorWithOptionalPagination(inner types.WalkReferencesInstructor,
 }
 
 func (s ReferenceService) GetRef(ctx context.Context,
-	request *rpc.GetRefRequest) (*rpc.GetRefResponse, error) {
-	base := request.GetBase()
-	if base == nil {
+	request *rpc.GetRefRequest,
+) (*rpc.GetRefResponse, error) {
+	if request.Base == nil {
 		return nil, types.ErrBaseCannotBeEmpty
 	}
 
-	repoPath := getFullPathForRepo(s.reposRoot, base.GetRepoUid())
-
-	var refType types.RefType
-	switch request.RefType {
-	case rpc.GetRefRequest_Branch:
-		refType = types.RefTypeBranch
-	case rpc.GetRefRequest_Tag:
-		refType = types.RefTypeTag
-	default:
-		return nil, status.Error(codes.InvalidArgument, "invalid value of refType argument")
+	refType, ok := enum.RefFromRPC(request.GetRefType())
+	if !ok {
+		return nil, status.Error(codes.InvalidArgument, "invalid value of RefType argument")
 	}
 
+	repoPath := getFullPathForRepo(s.reposRoot, request.Base.GetRepoUid())
+
 	sha, err := s.adapter.GetRef(ctx, repoPath, request.RefName, refType)
 	if err != nil {
 		return nil, err
@@ -203,3 +199,25 @@ func (s ReferenceService) GetRef(ctx context.Context,
 
 	return &rpc.GetRefResponse{Sha: sha}, nil
 }
+
+func (s ReferenceService) UpdateRef(ctx context.Context,
+	request *rpc.UpdateRefRequest,
+) (*rpc.UpdateRefResponse, error) {
+	if request.Base == nil {
+		return nil, types.ErrBaseCannotBeEmpty
+	}
+
+	refType, ok := enum.RefFromRPC(request.GetRefType())
+	if !ok {
+		return nil, status.Error(codes.InvalidArgument, "invalid value of RefType argument")
+	}
+
+	repoPath := getFullPathForRepo(s.reposRoot, request.Base.GetRepoUid())
+
+	err := s.adapter.UpdateRef(ctx, repoPath, request.RefName, refType, request.NewValue, request.OldValue)
+	if err != nil {
+		return nil, err
+	}
+
+	return &rpc.UpdateRefResponse{}, nil
+}
diff --git a/gitrpc/internal/types/types.go b/gitrpc/internal/types/types.go
index 692f6e13f..65b5b1913 100644
--- a/gitrpc/internal/types/types.go
+++ b/gitrpc/internal/types/types.go
@@ -80,13 +80,6 @@ func ParseGitReferenceField(f string) (GitReferenceField, error) {
 	}
 }
 
-type RefType int
-
-const (
-	RefTypeBranch RefType = iota
-	RefTypeTag
-)
-
 type WalkInstruction int
 
 const (
diff --git a/gitrpc/proto/ref.proto b/gitrpc/proto/ref.proto
index 3785b78c9..8ef1e5b4b 100644
--- a/gitrpc/proto/ref.proto
+++ b/gitrpc/proto/ref.proto
@@ -11,6 +11,7 @@ service ReferenceService {
   rpc ListBranches(ListBranchesRequest) returns (stream ListBranchesResponse);
   rpc ListCommitTags(ListCommitTagsRequest) returns (stream ListCommitTagsResponse);
   rpc GetRef(GetRefRequest) returns (GetRefResponse);
+  rpc UpdateRef(UpdateRefRequest) returns (UpdateRefResponse);
 }
 
 message CreateBranchRequest {
@@ -89,12 +90,15 @@ message CommitTag {
   Commit commit     = 7;
 }
 
+enum RefType {
+  RefRaw = 0;
+  RefBranch = 1;
+  RefTag = 2;
+  RefPullReqHead = 3;
+  RefPullReqMerge = 4;
+}
+
 message GetRefRequest {
-  enum RefType {
-    Branch = 0;
-    Tag = 1;
-  }
-  
   ReadRequest base = 1;
   string ref_name  = 2;
   RefType ref_type = 3;
@@ -103,3 +107,13 @@ message GetRefRequest {
 message GetRefResponse {
   string sha = 1;
 }
+
+message UpdateRefRequest {
+  WriteRequest base = 1;
+  string ref_name  = 2;
+  RefType ref_type = 3;
+  string new_value = 4;
+  string old_value = 5;
+}
+
+message UpdateRefResponse {}
diff --git a/gitrpc/ref.go b/gitrpc/ref.go
index 9454231b1..9e341d0c2 100644
--- a/gitrpc/ref.go
+++ b/gitrpc/ref.go
@@ -7,42 +7,27 @@ package gitrpc
 import (
 	"context"
 
+	"github.com/harness/gitness/gitrpc/enum"
 	"github.com/harness/gitness/gitrpc/rpc"
 
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )
 
-type RefType int
-
-const (
-	RefTypeBranch RefType = iota
-	RefTypeTag
-)
-
 type GetRefParams struct {
 	ReadParams
 	Name string
-	Type RefType
+	Type enum.RefType
 }
 
 type GetRefResponse struct {
 	SHA string
 }
 
-func (c *Client) GetRef(ctx context.Context, params *GetRefParams) (*GetRefResponse, error) {
-	if params == nil {
-		return nil, ErrNoParamsProvided
-	}
-
-	var refType rpc.GetRefRequest_RefType
-	switch params.Type {
-	case RefTypeBranch:
-		refType = rpc.GetRefRequest_Branch
-	case RefTypeTag:
-		refType = rpc.GetRefRequest_Tag
-	default:
-		return nil, ErrInvalidArgument
+func (c *Client) GetRef(ctx context.Context, params GetRefParams) (GetRefResponse, error) {
+	refType, isOk := enum.RefToRPC(params.Type)
+	if !isOk {
+		return GetRefResponse{}, ErrInvalidArgument
 	}
 
 	result, err := c.refService.GetRef(ctx, &rpc.GetRefRequest{
@@ -51,13 +36,36 @@ func (c *Client) GetRef(ctx context.Context, params *GetRefParams) (*GetRefRespo
 		RefType: refType,
 	})
 	if s, ok := status.FromError(err); err != nil && ok && s.Code() == codes.NotFound {
-		return nil, ErrNotFound
-	}
-	if err != nil {
-		return nil, err
+		return GetRefResponse{}, ErrNotFound
 	}
 
-	return &GetRefResponse{
-		SHA: result.Sha,
-	}, nil
+	return GetRefResponse{SHA: result.Sha}, nil
+}
+
+type UpdateRefParams struct {
+	WriteParams
+	Name     string
+	Type     enum.RefType
+	NewValue string
+	OldValue string
+}
+
+func (c *Client) UpdateRef(ctx context.Context, params UpdateRefParams) error {
+	refType, isOk := enum.RefToRPC(params.Type)
+	if !isOk {
+		return ErrInvalidArgument
+	}
+
+	_, err := c.refService.UpdateRef(ctx, &rpc.UpdateRefRequest{
+		Base:     mapToRPCWriteRequest(params.WriteParams),
+		RefName:  params.Name,
+		RefType:  refType,
+		NewValue: params.NewValue,
+		OldValue: params.OldValue,
+	})
+	if s, ok := status.FromError(err); err != nil && ok && s.Code() == codes.NotFound {
+		return ErrNotFound
+	}
+
+	return err
 }
diff --git a/gitrpc/rpc/ref.pb.go b/gitrpc/rpc/ref.pb.go
index 8cbfa3a7d..c0b4d7eac 100644
--- a/gitrpc/rpc/ref.pb.go
+++ b/gitrpc/rpc/ref.pb.go
@@ -20,6 +20,61 @@ const (
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
+type RefType int32
+
+const (
+	RefType_RefRaw          RefType = 0
+	RefType_RefBranch       RefType = 1
+	RefType_RefTag          RefType = 2
+	RefType_RefPullReqHead  RefType = 3
+	RefType_RefPullReqMerge RefType = 4
+)
+
+// Enum value maps for RefType.
+var (
+	RefType_name = map[int32]string{
+		0: "RefRaw",
+		1: "RefBranch",
+		2: "RefTag",
+		3: "RefPullReqHead",
+		4: "RefPullReqMerge",
+	}
+	RefType_value = map[string]int32{
+		"RefRaw":          0,
+		"RefBranch":       1,
+		"RefTag":          2,
+		"RefPullReqHead":  3,
+		"RefPullReqMerge": 4,
+	}
+)
+
+func (x RefType) Enum() *RefType {
+	p := new(RefType)
+	*p = x
+	return p
+}
+
+func (x RefType) String() string {
+	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
+}
+
+func (RefType) Descriptor() protoreflect.EnumDescriptor {
+	return file_ref_proto_enumTypes[0].Descriptor()
+}
+
+func (RefType) Type() protoreflect.EnumType {
+	return &file_ref_proto_enumTypes[0]
+}
+
+func (x RefType) Number() protoreflect.EnumNumber {
+	return protoreflect.EnumNumber(x)
+}
+
+// Deprecated: Use RefType.Descriptor instead.
+func (RefType) EnumDescriptor() ([]byte, []int) {
+	return file_ref_proto_rawDescGZIP(), []int{0}
+}
+
 type ListBranchesRequest_SortOption int32
 
 const (
@@ -53,11 +108,11 @@ func (x ListBranchesRequest_SortOption) String() string {
 }
 
 func (ListBranchesRequest_SortOption) Descriptor() protoreflect.EnumDescriptor {
-	return file_ref_proto_enumTypes[0].Descriptor()
+	return file_ref_proto_enumTypes[1].Descriptor()
 }
 
 func (ListBranchesRequest_SortOption) Type() protoreflect.EnumType {
-	return &file_ref_proto_enumTypes[0]
+	return &file_ref_proto_enumTypes[1]
 }
 
 func (x ListBranchesRequest_SortOption) Number() protoreflect.EnumNumber {
@@ -102,11 +157,11 @@ func (x ListCommitTagsRequest_SortOption) String() string {
 }
 
 func (ListCommitTagsRequest_SortOption) Descriptor() protoreflect.EnumDescriptor {
-	return file_ref_proto_enumTypes[1].Descriptor()
+	return file_ref_proto_enumTypes[2].Descriptor()
 }
 
 func (ListCommitTagsRequest_SortOption) Type() protoreflect.EnumType {
-	return &file_ref_proto_enumTypes[1]
+	return &file_ref_proto_enumTypes[2]
 }
 
 func (x ListCommitTagsRequest_SortOption) Number() protoreflect.EnumNumber {
@@ -118,52 +173,6 @@ func (ListCommitTagsRequest_SortOption) EnumDescriptor() ([]byte, []int) {
 	return file_ref_proto_rawDescGZIP(), []int{7, 0}
 }
 
-type GetRefRequest_RefType int32
-
-const (
-	GetRefRequest_Branch GetRefRequest_RefType = 0
-	GetRefRequest_Tag    GetRefRequest_RefType = 1
-)
-
-// Enum value maps for GetRefRequest_RefType.
-var (
-	GetRefRequest_RefType_name = map[int32]string{
-		0: "Branch",
-		1: "Tag",
-	}
-	GetRefRequest_RefType_value = map[string]int32{
-		"Branch": 0,
-		"Tag":    1,
-	}
-)
-
-func (x GetRefRequest_RefType) Enum() *GetRefRequest_RefType {
-	p := new(GetRefRequest_RefType)
-	*p = x
-	return p
-}
-
-func (x GetRefRequest_RefType) String() string {
-	return protoimpl.X.EnumStringOf(x.Descriptor(), protoreflect.EnumNumber(x))
-}
-
-func (GetRefRequest_RefType) Descriptor() protoreflect.EnumDescriptor {
-	return file_ref_proto_enumTypes[2].Descriptor()
-}
-
-func (GetRefRequest_RefType) Type() protoreflect.EnumType {
-	return &file_ref_proto_enumTypes[2]
-}
-
-func (x GetRefRequest_RefType) Number() protoreflect.EnumNumber {
-	return protoreflect.EnumNumber(x)
-}
-
-// Deprecated: Use GetRefRequest_RefType.Descriptor instead.
-func (GetRefRequest_RefType) EnumDescriptor() ([]byte, []int) {
-	return file_ref_proto_rawDescGZIP(), []int{10, 0}
-}
-
 type CreateBranchRequest struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -831,9 +840,9 @@ type GetRefRequest struct {
 	sizeCache     protoimpl.SizeCache
 	unknownFields protoimpl.UnknownFields
 
-	Base    *ReadRequest          `protobuf:"bytes,1,opt,name=base,proto3" json:"base,omitempty"`
-	RefName string                `protobuf:"bytes,2,opt,name=ref_name,json=refName,proto3" json:"ref_name,omitempty"`
-	RefType GetRefRequest_RefType `protobuf:"varint,3,opt,name=ref_type,json=refType,proto3,enum=rpc.GetRefRequest_RefType" json:"ref_type,omitempty"`
+	Base    *ReadRequest `protobuf:"bytes,1,opt,name=base,proto3" json:"base,omitempty"`
+	RefName string       `protobuf:"bytes,2,opt,name=ref_name,json=refName,proto3" json:"ref_name,omitempty"`
+	RefType RefType      `protobuf:"varint,3,opt,name=ref_type,json=refType,proto3,enum=rpc.RefType" json:"ref_type,omitempty"`
 }
 
 func (x *GetRefRequest) Reset() {
@@ -882,11 +891,11 @@ func (x *GetRefRequest) GetRefName() string {
 	return ""
 }
 
-func (x *GetRefRequest) GetRefType() GetRefRequest_RefType {
+func (x *GetRefRequest) GetRefType() RefType {
 	if x != nil {
 		return x.RefType
 	}
-	return GetRefRequest_Branch
+	return RefType_RefRaw
 }
 
 type GetRefResponse struct {
@@ -936,6 +945,123 @@ func (x *GetRefResponse) GetSha() string {
 	return ""
 }
 
+type UpdateRefRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	Base     *WriteRequest `protobuf:"bytes,1,opt,name=base,proto3" json:"base,omitempty"`
+	RefName  string        `protobuf:"bytes,2,opt,name=ref_name,json=refName,proto3" json:"ref_name,omitempty"`
+	RefType  RefType       `protobuf:"varint,3,opt,name=ref_type,json=refType,proto3,enum=rpc.RefType" json:"ref_type,omitempty"`
+	NewValue string        `protobuf:"bytes,4,opt,name=new_value,json=newValue,proto3" json:"new_value,omitempty"`
+	OldValue string        `protobuf:"bytes,5,opt,name=old_value,json=oldValue,proto3" json:"old_value,omitempty"`
+}
+
+func (x *UpdateRefRequest) Reset() {
+	*x = UpdateRefRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_ref_proto_msgTypes[12]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *UpdateRefRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*UpdateRefRequest) ProtoMessage() {}
+
+func (x *UpdateRefRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_ref_proto_msgTypes[12]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use UpdateRefRequest.ProtoReflect.Descriptor instead.
+func (*UpdateRefRequest) Descriptor() ([]byte, []int) {
+	return file_ref_proto_rawDescGZIP(), []int{12}
+}
+
+func (x *UpdateRefRequest) GetBase() *WriteRequest {
+	if x != nil {
+		return x.Base
+	}
+	return nil
+}
+
+func (x *UpdateRefRequest) GetRefName() string {
+	if x != nil {
+		return x.RefName
+	}
+	return ""
+}
+
+func (x *UpdateRefRequest) GetRefType() RefType {
+	if x != nil {
+		return x.RefType
+	}
+	return RefType_RefRaw
+}
+
+func (x *UpdateRefRequest) GetNewValue() string {
+	if x != nil {
+		return x.NewValue
+	}
+	return ""
+}
+
+func (x *UpdateRefRequest) GetOldValue() string {
+	if x != nil {
+		return x.OldValue
+	}
+	return ""
+}
+
+type UpdateRefResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+}
+
+func (x *UpdateRefResponse) Reset() {
+	*x = UpdateRefResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_ref_proto_msgTypes[13]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *UpdateRefResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*UpdateRefResponse) ProtoMessage() {}
+
+func (x *UpdateRefResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_ref_proto_msgTypes[13]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use UpdateRefResponse.ProtoReflect.Descriptor instead.
+func (*UpdateRefResponse) Descriptor() ([]byte, []int) {
+	return file_ref_proto_rawDescGZIP(), []int{13}
+}
+
 var File_ref_proto protoreflect.FileDescriptor
 
 var file_ref_proto_rawDesc = []byte{
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 var (
@@ -1081,11 +1227,11 @@ func file_ref_proto_rawDescGZIP() []byte {
 }
 
 var file_ref_proto_enumTypes = make([]protoimpl.EnumInfo, 3)
-var file_ref_proto_msgTypes = make([]protoimpl.MessageInfo, 12)
+var file_ref_proto_msgTypes = make([]protoimpl.MessageInfo, 14)
 var file_ref_proto_goTypes = []interface{}{
-	(ListBranchesRequest_SortOption)(0),   // 0: rpc.ListBranchesRequest.SortOption
-	(ListCommitTagsRequest_SortOption)(0), // 1: rpc.ListCommitTagsRequest.SortOption
-	(GetRefRequest_RefType)(0),            // 2: rpc.GetRefRequest.RefType
+	(RefType)(0),                          // 0: rpc.RefType
+	(ListBranchesRequest_SortOption)(0),   // 1: rpc.ListBranchesRequest.SortOption
+	(ListCommitTagsRequest_SortOption)(0), // 2: rpc.ListCommitTagsRequest.SortOption
 	(*CreateBranchRequest)(nil),           // 3: rpc.CreateBranchRequest
 	(*CreateBranchResponse)(nil),          // 4: rpc.CreateBranchResponse
 	(*DeleteBranchRequest)(nil),           // 5: rpc.DeleteBranchRequest
@@ -1098,44 +1244,50 @@ var file_ref_proto_goTypes = []interface{}{
 	(*CommitTag)(nil),                     // 12: rpc.CommitTag
 	(*GetRefRequest)(nil),                 // 13: rpc.GetRefRequest
 	(*GetRefResponse)(nil),                // 14: rpc.GetRefResponse
-	(*WriteRequest)(nil),                  // 15: rpc.WriteRequest
-	(*ReadRequest)(nil),                   // 16: rpc.ReadRequest
-	(SortOrder)(0),                        // 17: rpc.SortOrder
-	(*Commit)(nil),                        // 18: rpc.Commit
-	(*Signature)(nil),                     // 19: rpc.Signature
+	(*UpdateRefRequest)(nil),              // 15: rpc.UpdateRefRequest
+	(*UpdateRefResponse)(nil),             // 16: rpc.UpdateRefResponse
+	(*WriteRequest)(nil),                  // 17: rpc.WriteRequest
+	(*ReadRequest)(nil),                   // 18: rpc.ReadRequest
+	(SortOrder)(0),                        // 19: rpc.SortOrder
+	(*Commit)(nil),                        // 20: rpc.Commit
+	(*Signature)(nil),                     // 21: rpc.Signature
 }
 var file_ref_proto_depIdxs = []int32{
-	15, // 0: rpc.CreateBranchRequest.base:type_name -> rpc.WriteRequest
+	17, // 0: rpc.CreateBranchRequest.base:type_name -> rpc.WriteRequest
 	9,  // 1: rpc.CreateBranchResponse.branch:type_name -> rpc.Branch
-	15, // 2: rpc.DeleteBranchRequest.base:type_name -> rpc.WriteRequest
-	16, // 3: rpc.ListBranchesRequest.base:type_name -> rpc.ReadRequest
-	0,  // 4: rpc.ListBranchesRequest.sort:type_name -> rpc.ListBranchesRequest.SortOption
-	17, // 5: rpc.ListBranchesRequest.order:type_name -> rpc.SortOrder
+	17, // 2: rpc.DeleteBranchRequest.base:type_name -> rpc.WriteRequest
+	18, // 3: rpc.ListBranchesRequest.base:type_name -> rpc.ReadRequest
+	1,  // 4: rpc.ListBranchesRequest.sort:type_name -> rpc.ListBranchesRequest.SortOption
+	19, // 5: rpc.ListBranchesRequest.order:type_name -> rpc.SortOrder
 	9,  // 6: rpc.ListBranchesResponse.branch:type_name -> rpc.Branch
-	18, // 7: rpc.Branch.commit:type_name -> rpc.Commit
-	16, // 8: rpc.ListCommitTagsRequest.base:type_name -> rpc.ReadRequest
-	1,  // 9: rpc.ListCommitTagsRequest.sort:type_name -> rpc.ListCommitTagsRequest.SortOption
-	17, // 10: rpc.ListCommitTagsRequest.order:type_name -> rpc.SortOrder
+	20, // 7: rpc.Branch.commit:type_name -> rpc.Commit
+	18, // 8: rpc.ListCommitTagsRequest.base:type_name -> rpc.ReadRequest
+	2,  // 9: rpc.ListCommitTagsRequest.sort:type_name -> rpc.ListCommitTagsRequest.SortOption
+	19, // 10: rpc.ListCommitTagsRequest.order:type_name -> rpc.SortOrder
 	12, // 11: rpc.ListCommitTagsResponse.tag:type_name -> rpc.CommitTag
-	19, // 12: rpc.CommitTag.tagger:type_name -> rpc.Signature
-	18, // 13: rpc.CommitTag.commit:type_name -> rpc.Commit
-	16, // 14: rpc.GetRefRequest.base:type_name -> rpc.ReadRequest
-	2,  // 15: rpc.GetRefRequest.ref_type:type_name -> rpc.GetRefRequest.RefType
-	3,  // 16: rpc.ReferenceService.CreateBranch:input_type -> rpc.CreateBranchRequest
-	5,  // 17: rpc.ReferenceService.DeleteBranch:input_type -> rpc.DeleteBranchRequest
-	7,  // 18: rpc.ReferenceService.ListBranches:input_type -> rpc.ListBranchesRequest
-	10, // 19: rpc.ReferenceService.ListCommitTags:input_type -> rpc.ListCommitTagsRequest
-	13, // 20: rpc.ReferenceService.GetRef:input_type -> rpc.GetRefRequest
-	4,  // 21: rpc.ReferenceService.CreateBranch:output_type -> rpc.CreateBranchResponse
-	6,  // 22: rpc.ReferenceService.DeleteBranch:output_type -> rpc.DeleteBranchResponse
-	8,  // 23: rpc.ReferenceService.ListBranches:output_type -> rpc.ListBranchesResponse
-	11, // 24: rpc.ReferenceService.ListCommitTags:output_type -> rpc.ListCommitTagsResponse
-	14, // 25: rpc.ReferenceService.GetRef:output_type -> rpc.GetRefResponse
-	21, // [21:26] is the sub-list for method output_type
-	16, // [16:21] is the sub-list for method input_type
-	16, // [16:16] is the sub-list for extension type_name
-	16, // [16:16] is the sub-list for extension extendee
-	0,  // [0:16] is the sub-list for field type_name
+	21, // 12: rpc.CommitTag.tagger:type_name -> rpc.Signature
+	20, // 13: rpc.CommitTag.commit:type_name -> rpc.Commit
+	18, // 14: rpc.GetRefRequest.base:type_name -> rpc.ReadRequest
+	0,  // 15: rpc.GetRefRequest.ref_type:type_name -> rpc.RefType
+	17, // 16: rpc.UpdateRefRequest.base:type_name -> rpc.WriteRequest
+	0,  // 17: rpc.UpdateRefRequest.ref_type:type_name -> rpc.RefType
+	3,  // 18: rpc.ReferenceService.CreateBranch:input_type -> rpc.CreateBranchRequest
+	5,  // 19: rpc.ReferenceService.DeleteBranch:input_type -> rpc.DeleteBranchRequest
+	7,  // 20: rpc.ReferenceService.ListBranches:input_type -> rpc.ListBranchesRequest
+	10, // 21: rpc.ReferenceService.ListCommitTags:input_type -> rpc.ListCommitTagsRequest
+	13, // 22: rpc.ReferenceService.GetRef:input_type -> rpc.GetRefRequest
+	15, // 23: rpc.ReferenceService.UpdateRef:input_type -> rpc.UpdateRefRequest
+	4,  // 24: rpc.ReferenceService.CreateBranch:output_type -> rpc.CreateBranchResponse
+	6,  // 25: rpc.ReferenceService.DeleteBranch:output_type -> rpc.DeleteBranchResponse
+	8,  // 26: rpc.ReferenceService.ListBranches:output_type -> rpc.ListBranchesResponse
+	11, // 27: rpc.ReferenceService.ListCommitTags:output_type -> rpc.ListCommitTagsResponse
+	14, // 28: rpc.ReferenceService.GetRef:output_type -> rpc.GetRefResponse
+	16, // 29: rpc.ReferenceService.UpdateRef:output_type -> rpc.UpdateRefResponse
+	24, // [24:30] is the sub-list for method output_type
+	18, // [18:24] is the sub-list for method input_type
+	18, // [18:18] is the sub-list for extension type_name
+	18, // [18:18] is the sub-list for extension extendee
+	0,  // [0:18] is the sub-list for field type_name
 }
 
 func init() { file_ref_proto_init() }
@@ -1289,6 +1441,30 @@ func file_ref_proto_init() {
 				return nil
 			}
 		}
+		file_ref_proto_msgTypes[12].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*UpdateRefRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_ref_proto_msgTypes[13].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*UpdateRefResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
 	}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
@@ -1296,7 +1472,7 @@ func file_ref_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_ref_proto_rawDesc,
 			NumEnums:      3,
-			NumMessages:   12,
+			NumMessages:   14,
 			NumExtensions: 0,
 			NumServices:   1,
 		},
diff --git a/gitrpc/rpc/ref_grpc.pb.go b/gitrpc/rpc/ref_grpc.pb.go
index 56daa5da8..dc2b491be 100644
--- a/gitrpc/rpc/ref_grpc.pb.go
+++ b/gitrpc/rpc/ref_grpc.pb.go
@@ -27,6 +27,7 @@ type ReferenceServiceClient interface {
 	ListBranches(ctx context.Context, in *ListBranchesRequest, opts ...grpc.CallOption) (ReferenceService_ListBranchesClient, error)
 	ListCommitTags(ctx context.Context, in *ListCommitTagsRequest, opts ...grpc.CallOption) (ReferenceService_ListCommitTagsClient, error)
 	GetRef(ctx context.Context, in *GetRefRequest, opts ...grpc.CallOption) (*GetRefResponse, error)
+	UpdateRef(ctx context.Context, in *UpdateRefRequest, opts ...grpc.CallOption) (*UpdateRefResponse, error)
 }
 
 type referenceServiceClient struct {
@@ -128,6 +129,15 @@ func (c *referenceServiceClient) GetRef(ctx context.Context, in *GetRefRequest,
 	return out, nil
 }
 
+func (c *referenceServiceClient) UpdateRef(ctx context.Context, in *UpdateRefRequest, opts ...grpc.CallOption) (*UpdateRefResponse, error) {
+	out := new(UpdateRefResponse)
+	err := c.cc.Invoke(ctx, "/rpc.ReferenceService/UpdateRef", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 // ReferenceServiceServer is the server API for ReferenceService service.
 // All implementations must embed UnimplementedReferenceServiceServer
 // for forward compatibility
@@ -137,6 +147,7 @@ type ReferenceServiceServer interface {
 	ListBranches(*ListBranchesRequest, ReferenceService_ListBranchesServer) error
 	ListCommitTags(*ListCommitTagsRequest, ReferenceService_ListCommitTagsServer) error
 	GetRef(context.Context, *GetRefRequest) (*GetRefResponse, error)
+	UpdateRef(context.Context, *UpdateRefRequest) (*UpdateRefResponse, error)
 	mustEmbedUnimplementedReferenceServiceServer()
 }
 
@@ -159,6 +170,9 @@ func (UnimplementedReferenceServiceServer) ListCommitTags(*ListCommitTagsRequest
 func (UnimplementedReferenceServiceServer) GetRef(context.Context, *GetRefRequest) (*GetRefResponse, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method GetRef not implemented")
 }
+func (UnimplementedReferenceServiceServer) UpdateRef(context.Context, *UpdateRefRequest) (*UpdateRefResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method UpdateRef not implemented")
+}
 func (UnimplementedReferenceServiceServer) mustEmbedUnimplementedReferenceServiceServer() {}
 
 // UnsafeReferenceServiceServer may be embedded to opt out of forward compatibility for this service.
@@ -268,6 +282,24 @@ func _ReferenceService_GetRef_Handler(srv interface{}, ctx context.Context, dec
 	return interceptor(ctx, in, info, handler)
 }
 
+func _ReferenceService_UpdateRef_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(UpdateRefRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ReferenceServiceServer).UpdateRef(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/rpc.ReferenceService/UpdateRef",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ReferenceServiceServer).UpdateRef(ctx, req.(*UpdateRefRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 // ReferenceService_ServiceDesc is the grpc.ServiceDesc for ReferenceService service.
 // It's only intended for direct use with grpc.RegisterService,
 // and not to be introspected or modified (even as a copy)
@@ -287,6 +319,10 @@ var ReferenceService_ServiceDesc = grpc.ServiceDesc{
 			MethodName: "GetRef",
 			Handler:    _ReferenceService_GetRef_Handler,
 		},
+		{
+			MethodName: "UpdateRef",
+			Handler:    _ReferenceService_UpdateRef_Handler,
+		},
 	},
 	Streams: []grpc.StreamDesc{
 		{
diff --git a/internal/api/controller/pullreq/controller.go b/internal/api/controller/pullreq/controller.go
index 4b61a7ffe..b7bf55dfd 100644
--- a/internal/api/controller/pullreq/controller.go
+++ b/internal/api/controller/pullreq/controller.go
@@ -10,8 +10,8 @@ import (
 	"fmt"
 
 	"github.com/harness/gitness/gitrpc"
+	gitrpcenum "github.com/harness/gitness/gitrpc/enum"
 	apiauth "github.com/harness/gitness/internal/api/auth"
-	repoctrl "github.com/harness/gitness/internal/api/controller/repo"
 	"github.com/harness/gitness/internal/api/usererror"
 	"github.com/harness/gitness/internal/auth"
 	"github.com/harness/gitness/internal/auth/authz"
@@ -64,27 +64,28 @@ func NewController(
 
 func (c *Controller) verifyBranchExistence(ctx context.Context,
 	repo *types.Repository, branch string,
-) error {
+) (string, error) {
 	if branch == "" {
-		return usererror.BadRequest("branch name can't be empty")
+		return "", usererror.BadRequest("branch name can't be empty")
 	}
 
-	_, err := c.gitRPCClient.GetRef(ctx,
-		&gitrpc.GetRefParams{
-			ReadParams: repoctrl.CreateRPCReadParams(repo),
+	ref, err := c.gitRPCClient.GetRef(ctx,
+		gitrpc.GetRefParams{
+			ReadParams: gitrpc.ReadParams{RepoUID: repo.GitUID},
 			Name:       branch,
-			Type:       gitrpc.RefTypeBranch})
+			Type:       gitrpcenum.RefTypeBranch,
+		})
 	if errors.Is(err, gitrpc.ErrNotFound) {
-		return usererror.BadRequest(
+		return "", usererror.BadRequest(
 			fmt.Sprintf("branch %s does not exist in the repository %s", branch, repo.UID))
 	}
 	if err != nil {
-		return fmt.Errorf(
+		return "", fmt.Errorf(
 			"failed to check existence of the branch %s in the repository %s: %w",
 			branch, repo.UID, err)
 	}
 
-	return nil
+	return ref.SHA, nil
 }
 
 func (c *Controller) getRepoCheckAccess(ctx context.Context,
diff --git a/internal/api/controller/pullreq/pr_create.go b/internal/api/controller/pullreq/pr_create.go
index 87f9dcc07..80a6b1817 100644
--- a/internal/api/controller/pullreq/pr_create.go
+++ b/internal/api/controller/pullreq/pr_create.go
@@ -54,11 +54,14 @@ func (c *Controller) Create(
 		return nil, usererror.BadRequest("target and source branch can't be the same")
 	}
 
-	if errBranch := c.verifyBranchExistence(ctx, sourceRepo, in.SourceBranch); errBranch != nil {
-		return nil, errBranch
+	var sourceSHA string
+
+	if sourceSHA, err = c.verifyBranchExistence(ctx, sourceRepo, in.SourceBranch); err != nil {
+		return nil, err
 	}
-	if errBranch := c.verifyBranchExistence(ctx, targetRepo, in.TargetBranch); errBranch != nil {
-		return nil, errBranch
+
+	if _, err = c.verifyBranchExistence(ctx, targetRepo, in.TargetBranch); err != nil {
+		return nil, err
 	}
 
 	if err = c.checkIfAlreadyExists(ctx, targetRepo.ID, sourceRepo.ID, in.SourceBranch, in.TargetBranch); err != nil {
@@ -73,6 +76,8 @@ func (c *Controller) Create(
 		return nil, fmt.Errorf("failed to aquire PullReqSeq number: %w", err)
 	}
 
+	_ = fmt.Sprintf("TODO: %s", sourceSHA) // TODO: Use sourceSHA to create git PR head ref
+
 	pr := newPullReq(session, targetRepo.PullReqSeq, sourceRepo, targetRepo, in)
 
 	err = c.pullreqStore.Create(ctx, pr)
diff --git a/internal/api/controller/pullreq/review_submit.go b/internal/api/controller/pullreq/review_submit.go
index a59676b0d..e38f88421 100644
--- a/internal/api/controller/pullreq/review_submit.go
+++ b/internal/api/controller/pullreq/review_submit.go
@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/harness/gitness/gitrpc"
+	gitrpcenum "github.com/harness/gitness/gitrpc/enum"
 	"github.com/harness/gitness/internal/api/usererror"
 	"github.com/harness/gitness/internal/auth"
 	"github.com/harness/gitness/internal/store"
@@ -69,16 +70,16 @@ func (c *Controller) ReviewSubmit(
 		return nil, usererror.BadRequest("Can't submit review to own pull requests.")
 	}
 
-	ref, err := c.gitRPCClient.GetRef(ctx, &gitrpc.GetRefParams{
+	ref, err := c.gitRPCClient.GetRef(ctx, gitrpc.GetRefParams{
 		ReadParams: gitrpc.ReadParams{RepoUID: repo.GitUID},
 		Name:       pr.TargetBranch,
-		Type:       gitrpc.RefTypeBranch,
+		Type:       gitrpcenum.RefTypeBranch,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("failed to get git branch sha: %w", err)
 	}
 
-	if ref == nil || ref.SHA == "" {
+	if ref.SHA == "" {
 		return nil, usererror.BadRequest("Failed to get branch SHA. Does the branch still exist?")
 	}