Move git diff codes from models to services/gitdiff (#7889)

* move git diff codes from models to services/gitdiff

* fix template

* fix test

* fix template

15 files changed, 164 insertions, 111 deletions

diff --git a/models/issue_comment.go b/models/issue_comment.go
index ad1a59e9d3..2a9e8596cb 100644
--- a/models/issue_comment.go
+++ b/models/issue_comment.go
@@ -7,7 +7,6 @@
 package models
 
 import (
-	"bytes"
 	"fmt"
 	"strings"
 
@@ -15,7 +14,6 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
-	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/timeutil"
 
@@ -488,32 +486,6 @@ func (c *Comment) UnsignedLine() uint64 {
 	return uint64(c.Line)
 }
 
-// AsDiff returns c.Patch as *Diff
-func (c *Comment) AsDiff() (*Diff, error) {
-	diff, err := ParsePatch(setting.Git.MaxGitDiffLines,
-		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles, strings.NewReader(c.Patch))
-	if err != nil {
-		return nil, err
-	}
-	if len(diff.Files) == 0 {
-		return nil, fmt.Errorf("no file found for comment ID: %d", c.ID)
-	}
-	secs := diff.Files[0].Sections
-	if len(secs) == 0 {
-		return nil, fmt.Errorf("no sections found for comment ID: %d", c.ID)
-	}
-	return diff, nil
-}
-
-// MustAsDiff executes AsDiff and logs the error instead of returning
-func (c *Comment) MustAsDiff() *Diff {
-	diff, err := c.AsDiff()
-	if err != nil {
-		log.Warn("MustAsDiff: %v", err)
-	}
-	return diff
-}
-
 // CodeCommentURL returns the url to a comment in code
 func (c *Comment) CodeCommentURL() string {
 	err := c.LoadIssue()
@@ -873,59 +845,6 @@ func CreateIssueComment(doer *User, repo *Repository, issue *Issue, content stri
 	return comment, nil
 }
 
-// CreateCodeComment creates a plain code comment at the specified line / path
-func CreateCodeComment(doer *User, repo *Repository, issue *Issue, content, treePath string, line, reviewID int64) (*Comment, error) {
-	var commitID, patch string
-	pr, err := GetPullRequestByIssueID(issue.ID)
-	if err != nil {
-		return nil, fmt.Errorf("GetPullRequestByIssueID: %v", err)
-	}
-	if err := pr.GetBaseRepo(); err != nil {
-		return nil, fmt.Errorf("GetHeadRepo: %v", err)
-	}
-	gitRepo, err := git.OpenRepository(pr.BaseRepo.RepoPath())
-	if err != nil {
-		return nil, fmt.Errorf("OpenRepository: %v", err)
-	}
-
-	// FIXME validate treePath
-	// Get latest commit referencing the commented line
-	// No need for get commit for base branch changes
-	if line > 0 {
-		commit, err := gitRepo.LineBlame(pr.GetGitRefName(), gitRepo.Path, treePath, uint(line))
-		if err == nil {
-			commitID = commit.ID.String()
-		} else if !strings.Contains(err.Error(), "exit status 128 - fatal: no such path") {
-			return nil, fmt.Errorf("LineBlame[%s, %s, %s, %d]: %v", pr.GetGitRefName(), gitRepo.Path, treePath, line, err)
-		}
-	}
-
-	// Only fetch diff if comment is review comment
-	if reviewID != 0 {
-		headCommitID, err := gitRepo.GetRefCommitID(pr.GetGitRefName())
-		if err != nil {
-			return nil, fmt.Errorf("GetRefCommitID[%s]: %v", pr.GetGitRefName(), err)
-		}
-		patchBuf := new(bytes.Buffer)
-		if err := GetRawDiffForFile(gitRepo.Path, pr.MergeBase, headCommitID, RawDiffNormal, treePath, patchBuf); err != nil {
-			return nil, fmt.Errorf("GetRawDiffForLine[%s, %s, %s, %s]: %v", err, gitRepo.Path, pr.MergeBase, headCommitID, treePath)
-		}
-		patch = CutDiffAroundLine(patchBuf, int64((&Comment{Line: line}).UnsignedLine()), line < 0, setting.UI.CodeCommentLines)
-	}
-	return CreateComment(&CreateCommentOptions{
-		Type:      CommentTypeCode,
-		Doer:      doer,
-		Repo:      repo,
-		Issue:     issue,
-		Content:   content,
-		LineNum:   line,
-		TreePath:  treePath,
-		CommitSHA: commitID,
-		ReviewID:  reviewID,
-		Patch:     patch,
-	})
-}
-
 // CreateRefComment creates a commit reference comment to issue.
 func CreateRefComment(doer *User, repo *Repository, issue *Issue, content, commitSHA string) error {
 	if len(commitSHA) == 0 {
diff --git a/models/models.go b/models/models.go
index 04acc77aa9..e802a35a77 100644
--- a/models/models.go
+++ b/models/models.go
@@ -250,3 +250,8 @@ func MaxBatchInsertSize(bean interface{}) int {
 	t := x.TableInfo(bean)
 	return 999 / len(t.ColumnsSeq())
 }
+
+// Count returns records number according struct's fields as database query conditions
+func Count(bean interface{}) (int64, error) {
+	return x.Count(bean)
+}
diff --git a/modules/repofiles/diff.go b/modules/repofiles/diff.go
index 3b5de5fa6f..c98bbc7684 100644
--- a/modules/repofiles/diff.go
+++ b/modules/repofiles/diff.go
@@ -8,10 +8,11 @@ import (
 	"strings"
 
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/services/gitdiff"
 )
 
 // GetDiffPreview produces and returns diff result of a file which is not yet committed.
-func GetDiffPreview(repo *models.Repository, branch, treePath, content string) (*models.Diff, error) {
+func GetDiffPreview(repo *models.Repository, branch, treePath, content string) (*gitdiff.Diff, error) {
 	if branch == "" {
 		branch = repo.DefaultBranch
 	}
diff --git a/modules/repofiles/diff_test.go b/modules/repofiles/diff_test.go
index bc7d4ebad6..de5ed1d754 100644
--- a/modules/repofiles/diff_test.go
+++ b/modules/repofiles/diff_test.go
@@ -9,6 +9,7 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/test"
+	"code.gitea.io/gitea/services/gitdiff"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -25,10 +26,10 @@ func TestGetDiffPreview(t *testing.T) {
 	treePath := "README.md"
 	content := "# repo1\n\nDescription for repo1\nthis is a new line"
 
-	expectedDiff := &models.Diff{
+	expectedDiff := &gitdiff.Diff{
 		TotalAddition: 2,
 		TotalDeletion: 1,
-		Files: []*models.DiffFile{
+		Files: []*gitdiff.DiffFile{
 			{
 				Name:        "README.md",
 				OldName:     "README.md",
@@ -42,10 +43,10 @@ func TestGetDiffPreview(t *testing.T) {
 				IsLFSFile:   false,
 				IsRenamed:   false,
 				IsSubmodule: false,
-				Sections: []*models.DiffSection{
+				Sections: []*gitdiff.DiffSection{
 					{
 						Name: "",
-						Lines: []*models.DiffLine{
+						Lines: []*gitdiff.DiffLine{
 							{
 								LeftIdx:  0,
 								RightIdx: 0,
diff --git a/modules/repofiles/temp_repo.go b/modules/repofiles/temp_repo.go
index d640ba80b0..f791c3cb96 100644
--- a/modules/repofiles/temp_repo.go
+++ b/modules/repofiles/temp_repo.go
@@ -20,6 +20,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/process"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/gitdiff"
 )
 
 // TemporaryUploadRepository is a type to wrap our upload repositories as a shallow clone
@@ -290,7 +291,7 @@ func (t *TemporaryUploadRepository) Push(doer *models.User, commitHash string, b
 }
 
 // DiffIndex returns a Diff of the current index to the head
-func (t *TemporaryUploadRepository) DiffIndex() (diff *models.Diff, err error) {
+func (t *TemporaryUploadRepository) DiffIndex() (diff *gitdiff.Diff, err error) {
 	timeout := 5 * time.Minute
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 	defer cancel()
@@ -313,7 +314,7 @@ func (t *TemporaryUploadRepository) DiffIndex() (diff *models.Diff, err error) {
 	pid := process.GetManager().Add(fmt.Sprintf("diffIndex [repo_path: %s]", t.repo.RepoPath()), cmd)
 	defer process.GetManager().Remove(pid)
 
-	diff, err = models.ParsePatch(setting.Git.MaxGitDiffLines, setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles, stdout)
+	diff, err = gitdiff.ParsePatch(setting.Git.MaxGitDiffLines, setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles, stdout)
 	if err != nil {
 		return nil, fmt.Errorf("ParsePatch: %v", err)
 	}
diff --git a/modules/templates/helper.go b/modules/templates/helper.go
index e0285808f8..147df3a788 100644
--- a/modules/templates/helper.go
+++ b/modules/templates/helper.go
@@ -27,6 +27,7 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/services/gitdiff"
 
 	"gopkg.in/editorconfig/editorconfig-core-go.v1"
 )
@@ -230,6 +231,7 @@ func NewFuncMap() []template.FuncMap {
 			}
 			return float32(n) * 100 / float32(sum)
 		},
+		"CommentMustAsDiff": gitdiff.CommentMustAsDiff,
 	}}
 }
 
diff --git a/routers/repo/commit.go b/routers/repo/commit.go
index 79fa024dc9..c3181cbe46 100644
--- a/routers/repo/commit.go
+++ b/routers/repo/commit.go
@@ -16,6 +16,7 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/gitdiff"
 )
 
 const (
@@ -217,7 +218,7 @@ func Diff(ctx *context.Context) {
 
 	ctx.Data["CommitStatus"] = models.CalcCommitStatus(statuses)
 
-	diff, err := models.GetDiffCommit(models.RepoPath(userName, repoName),
+	diff, err := gitdiff.GetDiffCommit(models.RepoPath(userName, repoName),
 		commitID, setting.Git.MaxGitDiffLines,
 		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles)
 	if err != nil {
@@ -269,10 +270,10 @@ func Diff(ctx *context.Context) {
 
 // RawDiff dumps diff results of repository in given commit ID to io.Writer
 func RawDiff(ctx *context.Context) {
-	if err := models.GetRawDiff(
+	if err := gitdiff.GetRawDiff(
 		models.RepoPath(ctx.Repo.Owner.Name, ctx.Repo.Repository.Name),
 		ctx.Params(":sha"),
-		models.RawDiffType(ctx.Params(":ext")),
+		gitdiff.RawDiffType(ctx.Params(":ext")),
 		ctx.Resp,
 	); err != nil {
 		ctx.ServerError("GetRawDiff", err)
diff --git a/routers/repo/compare.go b/routers/repo/compare.go
index 193255ca6c..4f9a918a7c 100644
--- a/routers/repo/compare.go
+++ b/routers/repo/compare.go
@@ -14,6 +14,7 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/gitdiff"
 )
 
 const (
@@ -230,7 +231,7 @@ func PrepareCompareDiff(
 		return true
 	}
 
-	diff, err := models.GetDiffRange(models.RepoPath(headUser.Name, headRepo.Name),
+	diff, err := gitdiff.GetDiffRange(models.RepoPath(headUser.Name, headRepo.Name),
 		compareInfo.MergeBase, headCommitID, setting.Git.MaxGitDiffLines,
 		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles)
 	if err != nil {
diff --git a/routers/repo/pull.go b/routers/repo/pull.go
index 22ccc7769c..14d2f50821 100644
--- a/routers/repo/pull.go
+++ b/routers/repo/pull.go
@@ -24,6 +24,7 @@ import (
 	"code.gitea.io/gitea/modules/pull"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/services/gitdiff"
 
 	"github.com/unknwon/com"
 )
@@ -517,7 +518,7 @@ func ViewPullFiles(ctx *context.Context) {
 		ctx.Data["Reponame"] = pull.HeadRepo.Name
 	}
 
-	diff, err := models.GetDiffRangeWithWhitespaceBehavior(diffRepoPath,
+	diff, err := gitdiff.GetDiffRangeWithWhitespaceBehavior(diffRepoPath,
 		startCommitID, endCommitID, setting.Git.MaxGitDiffLines,
 		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles,
 		whitespaceFlags[ctx.Data["WhitespaceBehavior"].(string)])
diff --git a/routers/repo/pull_review.go b/routers/repo/pull_review.go
index cf93783042..d4e3a3326a 100644
--- a/routers/repo/pull_review.go
+++ b/routers/repo/pull_review.go
@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/notification"
 	pull_service "code.gitea.io/gitea/modules/pull"
+	comment_service "code.gitea.io/gitea/services/comments"
 )
 
 // CreateCodeComment will create a code comment including an pending review if required
@@ -69,7 +70,7 @@ func CreateCodeComment(ctx *context.Context, form auth.CodeCommentForm) {
 		review.ID = form.Reply
 	}
 	//FIXME check if line, commit and treepath exist
-	comment, err := models.CreateCodeComment(
+	comment, err := comment_service.CreateCodeComment(
 		ctx.User,
 		issue.Repo,
 		issue,
diff --git a/services/comments/comments.go b/services/comments/comments.go
new file mode 100644
index 0000000000..bd261ff0a5
--- /dev/null
+++ b/services/comments/comments.go
@@ -0,0 +1,69 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package comments
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/gitdiff"
+)
+
+// CreateCodeComment creates a plain code comment at the specified line / path
+func CreateCodeComment(doer *models.User, repo *models.Repository, issue *models.Issue, content, treePath string, line, reviewID int64) (*models.Comment, error) {
+	var commitID, patch string
+	pr, err := models.GetPullRequestByIssueID(issue.ID)
+	if err != nil {
+		return nil, fmt.Errorf("GetPullRequestByIssueID: %v", err)
+	}
+	if err := pr.GetBaseRepo(); err != nil {
+		return nil, fmt.Errorf("GetHeadRepo: %v", err)
+	}
+	gitRepo, err := git.OpenRepository(pr.BaseRepo.RepoPath())
+	if err != nil {
+		return nil, fmt.Errorf("OpenRepository: %v", err)
+	}
+
+	// FIXME validate treePath
+	// Get latest commit referencing the commented line
+	// No need for get commit for base branch changes
+	if line > 0 {
+		commit, err := gitRepo.LineBlame(pr.GetGitRefName(), gitRepo.Path, treePath, uint(line))
+		if err == nil {
+			commitID = commit.ID.String()
+		} else if !strings.Contains(err.Error(), "exit status 128 - fatal: no such path") {
+			return nil, fmt.Errorf("LineBlame[%s, %s, %s, %d]: %v", pr.GetGitRefName(), gitRepo.Path, treePath, line, err)
+		}
+	}
+
+	// Only fetch diff if comment is review comment
+	if reviewID != 0 {
+		headCommitID, err := gitRepo.GetRefCommitID(pr.GetGitRefName())
+		if err != nil {
+			return nil, fmt.Errorf("GetRefCommitID[%s]: %v", pr.GetGitRefName(), err)
+		}
+		patchBuf := new(bytes.Buffer)
+		if err := gitdiff.GetRawDiffForFile(gitRepo.Path, pr.MergeBase, headCommitID, gitdiff.RawDiffNormal, treePath, patchBuf); err != nil {
+			return nil, fmt.Errorf("GetRawDiffForLine[%s, %s, %s, %s]: %v", err, gitRepo.Path, pr.MergeBase, headCommitID, treePath)
+		}
+		patch = gitdiff.CutDiffAroundLine(patchBuf, int64((&models.Comment{Line: line}).UnsignedLine()), line < 0, setting.UI.CodeCommentLines)
+	}
+	return models.CreateComment(&models.CreateCommentOptions{
+		Type:      models.CommentTypeCode,
+		Doer:      doer,
+		Repo:      repo,
+		Issue:     issue,
+		Content:   content,
+		LineNum:   line,
+		TreePath:  treePath,
+		CommitSHA: commitID,
+		ReviewID:  reviewID,
+		Patch:     patch,
+	})
+}
diff --git a/models/git_diff.go b/services/gitdiff/gitdiff.go
index b822685409..c2c5675d9f 100644
--- a/models/git_diff.go
+++ b/services/gitdiff/gitdiff.go
@@ -1,8 +1,9 @@
 // Copyright 2014 The Gogs Authors. All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
 // Use of this source code is governed by a MIT-style
 // license that can be found in the LICENSE file.
 
-package models
+package gitdiff
 
 import (
 	"bufio"
@@ -19,6 +20,7 @@ import (
 	"strconv"
 	"strings"
 
+	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/highlight"
@@ -60,7 +62,7 @@ type DiffLine struct {
 	RightIdx int
 	Type     DiffLineType
 	Content  string
-	Comments []*Comment
+	Comments []*models.Comment
 }
 
 // GetType returns the type of a DiffLine.
@@ -254,8 +256,8 @@ type Diff struct {
 }
 
 // LoadComments loads comments into each line
-func (diff *Diff) LoadComments(issue *Issue, currentUser *User) error {
-	allComments, err := FetchCodeComments(issue, currentUser)
+func (diff *Diff) LoadComments(issue *models.Issue, currentUser *models.User) error {
+	allComments, err := models.FetchCodeComments(issue, currentUser)
 	if err != nil {
 		return err
 	}
@@ -472,16 +474,16 @@ func ParsePatch(maxLines, maxLineCharacters, maxFiles int, reader io.Reader) (*D
 
 		trimLine := strings.Trim(line, "+- ")
 
-		if trimLine == LFSMetaFileIdentifier {
+		if trimLine == models.LFSMetaFileIdentifier {
 			curFileLFSPrefix = true
 		}
 
-		if curFileLFSPrefix && strings.HasPrefix(trimLine, LFSMetaFileOidPrefix) {
-			oid := strings.TrimPrefix(trimLine, LFSMetaFileOidPrefix)
+		if curFileLFSPrefix && strings.HasPrefix(trimLine, models.LFSMetaFileOidPrefix) {
+			oid := strings.TrimPrefix(trimLine, models.LFSMetaFileOidPrefix)
 
 			if len(oid) == 64 {
-				m := &LFSMetaObject{Oid: oid}
-				count, err := x.Count(m)
+				m := &models.LFSMetaObject{Oid: oid}
+				count, err := models.Count(m)
 
 				if err == nil && count > 0 {
 					curFile.IsBin = true
@@ -798,3 +800,29 @@ func GetRawDiffForFile(repoPath, startCommit, endCommit string, diffType RawDiff
 func GetDiffCommit(repoPath, commitID string, maxLines, maxLineCharacters, maxFiles int) (*Diff, error) {
 	return GetDiffRange(repoPath, "", commitID, maxLines, maxLineCharacters, maxFiles)
 }
+
+// CommentAsDiff returns c.Patch as *Diff
+func CommentAsDiff(c *models.Comment) (*Diff, error) {
+	diff, err := ParsePatch(setting.Git.MaxGitDiffLines,
+		setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles, strings.NewReader(c.Patch))
+	if err != nil {
+		return nil, err
+	}
+	if len(diff.Files) == 0 {
+		return nil, fmt.Errorf("no file found for comment ID: %d", c.ID)
+	}
+	secs := diff.Files[0].Sections
+	if len(secs) == 0 {
+		return nil, fmt.Errorf("no sections found for comment ID: %d", c.ID)
+	}
+	return diff, nil
+}
+
+// CommentMustAsDiff executes AsDiff and logs the error instead of returning
+func CommentMustAsDiff(c *models.Comment) *Diff {
+	diff, err := CommentAsDiff(c)
+	if err != nil {
+		log.Warn("CommentMustAsDiff: %v", err)
+	}
+	return diff
+}
diff --git a/models/git_diff_test.go b/services/gitdiff/gitdiff_test.go
index bf52095acf..acf3c6d7bd 100644
--- a/models/git_diff_test.go
+++ b/services/gitdiff/gitdiff_test.go
@@ -1,10 +1,16 @@
-package models
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package gitdiff
 
 import (
 	"html/template"
 	"strings"
 	"testing"
 
+	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/setting"
 
 	dmp "github.com/sergi/go-diff/diffmatchpatch"
@@ -168,23 +174,24 @@ func setupDefaultDiff() *Diff {
 	}
 }
 func TestDiff_LoadComments(t *testing.T) {
-	issue := AssertExistsAndLoadBean(t, &Issue{ID: 2}).(*Issue)
-	user := AssertExistsAndLoadBean(t, &User{ID: 1}).(*User)
+	assert.NoError(t, models.PrepareTestDatabase())
+
+	issue := models.AssertExistsAndLoadBean(t, &models.Issue{ID: 2}).(*models.Issue)
+	user := models.AssertExistsAndLoadBean(t, &models.User{ID: 1}).(*models.User)
 	diff := setupDefaultDiff()
-	assert.NoError(t, PrepareTestDatabase())
 	assert.NoError(t, diff.LoadComments(issue, user))
 	assert.Len(t, diff.Files[0].Sections[0].Lines[0].Comments, 2)
 }
 
 func TestDiffLine_CanComment(t *testing.T) {
 	assert.False(t, (&DiffLine{Type: DiffLineSection}).CanComment())
-	assert.False(t, (&DiffLine{Type: DiffLineAdd, Comments: []*Comment{{Content: "bla"}}}).CanComment())
+	assert.False(t, (&DiffLine{Type: DiffLineAdd, Comments: []*models.Comment{{Content: "bla"}}}).CanComment())
 	assert.True(t, (&DiffLine{Type: DiffLineAdd}).CanComment())
 	assert.True(t, (&DiffLine{Type: DiffLineDel}).CanComment())
 	assert.True(t, (&DiffLine{Type: DiffLinePlain}).CanComment())
 }
 
 func TestDiffLine_GetCommentSide(t *testing.T) {
-	assert.Equal(t, "previous", (&DiffLine{Comments: []*Comment{{Line: -3}}}).GetCommentSide())
-	assert.Equal(t, "proposed", (&DiffLine{Comments: []*Comment{{Line: 3}}}).GetCommentSide())
+	assert.Equal(t, "previous", (&DiffLine{Comments: []*models.Comment{{Line: -3}}}).GetCommentSide())
+	assert.Equal(t, "proposed", (&DiffLine{Comments: []*models.Comment{{Line: 3}}}).GetCommentSide())
 }
diff --git a/services/gitdiff/main_test.go b/services/gitdiff/main_test.go
new file mode 100644
index 0000000000..5ed3c75b70
--- /dev/null
+++ b/services/gitdiff/main_test.go
@@ -0,0 +1,16 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package gitdiff
+
+import (
+	"path/filepath"
+	"testing"
+
+	"code.gitea.io/gitea/models"
+)
+
+func TestMain(m *testing.M) {
+	models.MainTest(m, filepath.Join("..", ".."))
+}
diff --git a/templates/repo/issue/view_content/comments.tmpl b/templates/repo/issue/view_content/comments.tmpl
index 68303cf1ca..70de314c91 100644
--- a/templates/repo/issue/view_content/comments.tmpl
+++ b/templates/repo/issue/view_content/comments.tmpl
@@ -319,7 +319,7 @@
 							{{end}}
 								<a href="{{(index $comms 0).CodeCommentURL}}" class="file-comment">{{$filename}}</a>
 							</div>
-							{{$diff := ((index $comms 0).MustAsDiff)}}
+							{{$diff := (CommentMustAsDiff (index $comms 0))}}
 							{{if $diff}}
 								{{$file := (index $diff.Files 0)}}
 								<div id="code-preview-{{(index $comms 0).ID}}" class="ui table segment{{if $invalid}} hide{{end}}">