From ef0ce374a5b37478fbdce667372ccfb8fef0e5b6 Mon Sep 17 00:00:00 2001
From: Gusted <postmaster@gusted.xyz>
Date: Mon, 15 Apr 2024 20:45:59 +0200
Subject: [PATCH] [BUG] Use correct empty commit ID

- `RemoveFilesFromIndex` used an hardcoded empty commit ID for the SHA1
object format, this would result in an error if the repository was
initialized to use the sha256 object format. Get the object format of
the Git repository and use that to get the empty commit id.
- Adds unit test.
- Resolves #3184

(cherry picked from commit eeaef556c2d8cf41023ea4bcc07f7c18037583de)
---
 services/repository/files/temp_repo.go      |  9 ++++++-
 services/repository/files/temp_repo_test.go | 28 +++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 services/repository/files/temp_repo_test.go

diff --git a/services/repository/files/temp_repo.go b/services/repository/files/temp_repo.go
index 9fcd335c55..50b936cfa7 100644
--- a/services/repository/files/temp_repo.go
+++ b/services/repository/files/temp_repo.go
@@ -136,12 +136,19 @@ func (t *TemporaryUploadRepository) LsFiles(filenames ...string) ([]string, erro
 
 // RemoveFilesFromIndex removes the given files from the index
 func (t *TemporaryUploadRepository) RemoveFilesFromIndex(filenames ...string) error {
+	objectFormat, err := t.gitRepo.GetObjectFormat()
+	if err != nil {
+		return err
+	}
+
 	stdOut := new(bytes.Buffer)
 	stdErr := new(bytes.Buffer)
 	stdIn := new(bytes.Buffer)
 	for _, file := range filenames {
 		if file != "" {
-			stdIn.WriteString("0 0000000000000000000000000000000000000000\t")
+			stdIn.WriteString("0 ")
+			stdIn.WriteString(objectFormat.EmptyObjectID().String())
+			stdIn.WriteByte('\t')
 			stdIn.WriteString(file)
 			stdIn.WriteByte('\000')
 		}
diff --git a/services/repository/files/temp_repo_test.go b/services/repository/files/temp_repo_test.go
new file mode 100644
index 0000000000..2e31996c40
--- /dev/null
+++ b/services/repository/files/temp_repo_test.go
@@ -0,0 +1,28 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package files
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	"code.gitea.io/gitea/modules/git"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRemoveFilesFromIndexSha256(t *testing.T) {
+	if git.CheckGitVersionAtLeast("2.42") != nil {
+		t.Skip("skipping because installed Git version doesn't support SHA256")
+	}
+	unittest.PrepareTestEnv(t)
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+
+	temp, err := NewTemporaryUploadRepository(db.DefaultContext, repo)
+	assert.NoError(t, err)
+	assert.NoError(t, temp.Init("sha256"))
+	assert.NoError(t, temp.RemoveFilesFromIndex("README.md"))
+}