From d471755f689ecad1180c463cf56ac45c62b3362f Mon Sep 17 00:00:00 2001
From: bujjibabukatta <bujjibabukatta6@gmail.com>
Date: Mon, 15 Jun 2026 16:31:39 +0530
Subject: [PATCH] fix(gitlab): use diff_stats instead of changes_count for
 correct MR size (fixes #8888)

---
 .../add_additions_deletions_to_mr.go          | 32 +++++++++++++++++++
 .../models/migrationscripts/register.go       |  1 +
 backend/plugins/gitlab/models/mr.go           |  2 ++
 .../gitlab/tasks/mr_detail_collector.go       |  1 +
 backend/plugins/gitlab/tasks/mr_extractor.go  |  9 ++++++
 5 files changed, 45 insertions(+)
 create mode 100644 backend/plugins/gitlab/models/migrationscripts/add_additions_deletions_to_mr.go

diff --git a/backend/plugins/gitlab/models/migrationscripts/add_additions_deletions_to_mr.go b/backend/plugins/gitlab/models/migrationscripts/add_additions_deletions_to_mr.go
new file mode 100644
index 00000000000..e4691a5dab8
--- /dev/null
+++ b/backend/plugins/gitlab/models/migrationscripts/add_additions_deletions_to_mr.go
@@ -0,0 +1,32 @@
+package migrationscripts
+
+import (
+	"github.com/apache/incubator-devlake/core/context"
+	"github.com/apache/incubator-devlake/core/errors"
+	"github.com/apache/incubator-devlake/core/plugin"
+)
+
+var _ plugin.MigrationScript = (*addAdditionsDeletionsToMr)(nil)
+
+type mrAdditionsDeletions struct {
+	Additions int
+	Deletions int
+}
+
+func (mrAdditionsDeletions) TableName() string {
+	return "_tool_gitlab_merge_requests"
+}
+
+type addAdditionsDeletionsToMr struct{}
+
+func (*addAdditionsDeletionsToMr) Up(basicRes context.BasicRes) errors.Error {
+	return errors.Convert(basicRes.GetDal().AutoMigrate(&mrAdditionsDeletions{}))
+}
+
+func (*addAdditionsDeletionsToMr) Version() uint64 {
+	return 20260615000001
+}
+
+func (*addAdditionsDeletionsToMr) Name() string {
+	return "gitlab: add additions and deletions to merge requests"
+}
\ No newline at end of file
diff --git a/backend/plugins/gitlab/models/migrationscripts/register.go b/backend/plugins/gitlab/models/migrationscripts/register.go
index 30a76f63ed9..e684c953064 100644
--- a/backend/plugins/gitlab/models/migrationscripts/register.go
+++ b/backend/plugins/gitlab/models/migrationscripts/register.go
@@ -53,5 +53,6 @@ func All() []plugin.MigrationScript {
 		new(changeIssueComponentType),
 		new(addIsChildToPipelines240906),
 		new(addPrSizeExcludedFileExtensions),
+		new(addAdditionsDeletionsToMr),
 	}
 }
diff --git a/backend/plugins/gitlab/models/mr.go b/backend/plugins/gitlab/models/mr.go
index c25df4ba07f..57bf22a9c52 100644
--- a/backend/plugins/gitlab/models/mr.go
+++ b/backend/plugins/gitlab/models/mr.go
@@ -51,6 +51,8 @@ type GitlabMergeRequest struct {
 	AuthorUsername   string `gorm:"type:varchar(255)"`
 	AuthorUserId     int
 	Component        string `gorm:"type:varchar(255)"`
+	Additions         int        `gorm:"comment:Lines added in this MR diff only"`
+	Deletions         int        `gorm:"comment:Lines deleted in this MR diff only"`
 	common.NoPKModel
 }
 
diff --git a/backend/plugins/gitlab/tasks/mr_detail_collector.go b/backend/plugins/gitlab/tasks/mr_detail_collector.go
index bfb64f031b5..d20e96a1ec9 100644
--- a/backend/plugins/gitlab/tasks/mr_detail_collector.go
+++ b/backend/plugins/gitlab/tasks/mr_detail_collector.go
@@ -62,6 +62,7 @@ func CollectApiMergeRequestDetails(taskCtx plugin.SubTaskContext) errors.Error {
 		Query: func(reqData *helper.RequestData) (url.Values, errors.Error) {
 			query := url.Values{}
 			query.Set("with_stats", "true")
+			query.Set("include_diff_stats", "true")
 			return query, nil
 		},
 		ResponseParser: GetOneRawMessageFromResponse,
diff --git a/backend/plugins/gitlab/tasks/mr_extractor.go b/backend/plugins/gitlab/tasks/mr_extractor.go
index 3a8457b0cf0..6f559909eed 100644
--- a/backend/plugins/gitlab/tasks/mr_extractor.go
+++ b/backend/plugins/gitlab/tasks/mr_extractor.go
@@ -65,6 +65,13 @@ type MergeRequestRes struct {
 	Assignees        []Assignee
 	FirstCommentTime common.Iso8601Time
 	Labels           []string `json:"labels"`
+	DiffStats        struct {
+
+		Additions int `json:"additions"`
+
+		Deletions int `json:"deletions"`
+
+	} `json:"diff_stats"`
 }
 
 type Reviewer struct {
@@ -245,6 +252,8 @@ func convertMergeRequest(mr *MergeRequestRes) (*models.GitlabMergeRequest, error
 		MergedByUsername: mr.MergedBy.Username,
 		AuthorUsername:   mr.Author.Username,
 		AuthorUserId:     mr.Author.Id,
+		Additions:        mr.DiffStats.Additions,
+		Deletions:        mr.DiffStats.Deletions,
 	}
 	return gitlabMergeRequest, nil
 }