Add git.DIFF_RENAME_THRESHOLD option

Author: silverwind

custom/conf/app.example.ini

@@ -733,6 +733,8 @@ LEVEL = Info
 ;DISABLE_CORE_PROTECT_NTFS=false
 ;; Disable the usage of using partial clones for git.
 ;DISABLE_PARTIAL_CLONE = false
+;; Set the similarity threshold passed to git rename detection via `--find-renames=<threshold>`
+;DIFF_RENAME_THRESHOLD = 50%
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Git Operation timeout in seconds

modules/setting/git.go

@@ -30,6 +30,7 @@ var Git = struct {
 	LargeObjectThreshold      int64
 	DisableCoreProtectNTFS    bool
 	DisablePartialClone       bool
+	DiffRenameThreshold       string
 	Timeout                   struct {
 		Default int
 		Migrate int
@@ -52,6 +53,7 @@ var Git = struct {
 	PullRequestPushMessage:    true,
 	LargeObjectThreshold:      1024 * 1024,
 	DisablePartialClone:       false,
+	DiffRenameThreshold:       "50%",
 	Timeout: struct {
 		Default int
 		Migrate int

services/gitdiff/git_diff_tree.go

@@ -15,6 +15,7 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/git/gitcmd"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
 )
 
 type DiffTree struct {
@@ -56,7 +57,8 @@ func runGitDiffTree(ctx context.Context, gitRepo *git.Repository, useMergeBase b
 		return nil, err
 	}
 
-	cmd := gitcmd.NewCommand("diff-tree", "--raw", "-r", "--find-renames", "--root")
+	cmd := gitcmd.NewCommand("diff-tree", "--raw", "-r", "--root")
+	cmd.AddOptionFormat("--find-renames=%s", setting.Git.DiffRenameThreshold)
 	if useMergeBase {
 		cmd.AddArguments("--merge-base")
 	}

services/gitdiff/gitdiff.go

@@ -1225,7 +1225,7 @@ func getDiffBasic(ctx context.Context, gitRepo *git.Repository, opts *DiffOption
 	}
 
 	cmdDiff := gitcmd.NewCommand().
-		AddArguments("diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M").
+		AddArguments("diff", "--src-prefix=\\a/", "--dst-prefix=\\b/").
 		AddArguments(opts.WhitespaceBehavior...)
 
 	// In git 2.31, git diff learned --skip-to which we can use to shortcut skip to file
@@ -1237,6 +1237,8 @@ func getDiffBasic(ctx context.Context, gitRepo *git.Repository, opts *DiffOption
 		parsePatchSkipToFile = ""
 	}
 
+	cmdDiff.AddOptionFormat("--find-renames=%s", setting.Git.DiffRenameThreshold)
+
 	cmdDiff.AddDynamicArguments(beforeCommitID.String(), opts.AfterCommitID)
 	cmdDiff.AddDashesAndList(files...)