chore: fix git diff render (#38746)

Fix a regression from #38517 (the tail section index is not correctly assigned). And add a test to cover GetDiffForRender.
2026-08-05 11:20:03 +00:00 · 2026-08-03 01:34:26 +08:00
parent 4e4ea75fb9
commit 7f7dc2d16c
3 changed files with 126 additions and 6 deletions
@@ -0,0 +1,118 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitdiff
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea.dev/modules/git"
+	"gitea.dev/modules/setting"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetDiffForRender(t *testing.T) {
+	repoDir := filepath.Join(t.TempDir(), "temp-repo")
+	require.NoError(t, git.InitRepositoryLocal(t.Context(), repoDir, false, git.Sha1ObjectFormat.Name()))
+
+	contentLeft := strings.Repeat("a\n", 20) +
+		"mark1\n" +
+		strings.Repeat("b\n", 10) +
+		"mark2\n" +
+		strings.Repeat("c\n", 40) +
+		"mark3\n" +
+		strings.Repeat("a\n", 30)
+	contentRight := strings.Repeat("a\n", 20-1) +
+		"mark1-x\n" +
+		strings.Repeat("b\n", 10+3) +
+		"mark2-x\n" +
+		strings.Repeat("c\n", 40-5) +
+		"mark3-x\n" +
+		strings.Repeat("a\n", 30)
+
+	gitRepo, err := git.OpenRepositoryLocal(t.Context(), repoDir)
+	require.NoError(t, err)
+	defer gitRepo.Close()
+
+	require.NoError(t, git.ForceFastImport(t.Context(), gitRepo, []git.FastImportCommit{
+		{Ref: "refs/heads/b1", Files: []git.FastImportFile{{Path: "foo.txt", Content: contentLeft}}},
+		{Ref: "refs/heads/b2", Files: []git.FastImportFile{{Path: "foo.txt", Content: contentRight}}},
+	}))
+
+	beforeCommit, err := gitRepo.GetBranchCommit(t.Context(), "b1")
+	require.NoError(t, err)
+	afterCommit, err := gitRepo.GetBranchCommit(t.Context(), "b2")
+	require.NoError(t, err)
+
+	diff, err := GetDiffForRender(t.Context(), "/any/repo-link", gitRepo, &DiffOptions{
+		BeforeCommitID:    beforeCommit.ID.String(),
+		AfterCommitID:     afterCommit.ID.String(),
+		MaxLines:          setting.Git.MaxGitDiffLines,
+		MaxLineCharacters: setting.Git.MaxGitDiffLineCharacters,
+		MaxFiles:          setting.Git.MaxGitDiffFiles,
+	})
+	require.NoError(t, err)
+	require.Len(t, diff.Files, 1)
+
+	type section struct {
+		ExpandDirection string
+
+		LastLeftIdx   int
+		LastRightIdx  int
+		LeftIdx       int
+		RightIdx      int
+		LeftHunkSize  int
+		RightHunkSize int
+	}
+	expectedSections := []section{
+		{
+			ExpandDirection: "up",
+			LeftIdx:         17,
+			RightIdx:        17,
+			LeftHunkSize:    8,
+			RightHunkSize:   7,
+		},
+		{
+			ExpandDirection: "single",
+			LastLeftIdx:     24,
+			LastRightIdx:    23,
+			LeftIdx:         29,
+			RightIdx:        28,
+			LeftHunkSize:    7,
+			RightHunkSize:   10,
+		},
+		{
+			ExpandDirection: "updown",
+			LastLeftIdx:     35,
+			LastRightIdx:    37,
+			LeftIdx:         65,
+			RightIdx:        67,
+			LeftHunkSize:    12,
+			RightHunkSize:   7,
+		},
+		{
+			ExpandDirection: "down",
+			LastLeftIdx:     76,
+			LastRightIdx:    73,
+			LeftIdx:         104,
+			RightIdx:        101,
+		},
+	}
+	for idx, exp := range expectedSections {
+		secLine := diff.Files[0].Sections[idx].Lines[0] // line 0 should be the "section info"
+		actual := section{
+			ExpandDirection: secLine.GetExpandDirection(),
+			LastLeftIdx:     secLine.SectionInfo.LastLeftIdx,
+			LastRightIdx:    secLine.SectionInfo.LastRightIdx,
+			LeftIdx:         secLine.SectionInfo.LeftIdx,
+			RightIdx:        secLine.SectionInfo.RightIdx,
+			LeftHunkSize:    secLine.SectionInfo.LeftHunkSize,
+			RightHunkSize:   secLine.SectionInfo.RightHunkSize,
+		}
+		assert.Equal(t, exp, actual, "idx=%d", idx)
+	}
+}