Simplify how git repositories are opened (#28937)

## Purpose
This is a refactor toward building an abstraction over managing git
repositories.
Afterwards, it does not matter anymore if they are stored on the local
disk or somewhere remote.

## What this PR changes
We used `git.OpenRepository` everywhere previously.
Now, we should split them into two distinct functions:

Firstly, there are temporary repositories which do not change:

```go
git.OpenRepository(ctx, diskPath)
```

Gitea managed repositories having a record in the database in the
`repository` table are moved into the new package `gitrepo`:

```go
gitrepo.OpenRepository(ctx, repo_model.Repo)
```

Why is `repo_model.Repository` the second parameter instead of file
path?
Because then we can easily adapt our repository storage strategy.
The repositories can be stored locally, however, they could just as well
be stored on a remote server.

## Further changes in other PRs
- A Git Command wrapper on package `gitrepo` could be created. i.e.
`NewCommand(ctx, repo_model.Repository, commands...)`. `git.RunOpts{Dir:
repo.RepoPath()}`, the directory should be empty before invoking this
method and it can be filled in the function only. #28940
- Remove the `RepoPath()`/`WikiPath()` functions to reduce the
possibility of mistakes.

---------

Co-authored-by: delvh <dev.lh@web.de>

routers/web/repo/commit.go

@@ -22,6 +22,7 @@ import (
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/gitgraph"
+	"code.gitea.io/gitea/modules/gitrepo"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
@@ -279,7 +280,7 @@ func Diff(ctx *context.Context) {
 	)
 
 	if ctx.Data["PageIsWiki"] != nil {
-		gitRepo, err = git.OpenRepository(ctx, ctx.Repo.Repository.WikiPath())
+		gitRepo, err = gitrepo.OpenWikiRepository(ctx, ctx.Repo.Repository)
 		if err != nil {
 			ctx.ServerError("Repo.GitRepo.GetCommit", err)
 			return
@@ -404,7 +405,7 @@ func Diff(ctx *context.Context) {
 func RawDiff(ctx *context.Context) {
 	var gitRepo *git.Repository
 	if ctx.Data["PageIsWiki"] != nil {
-		wikiRepo, err := git.OpenRepository(ctx, ctx.Repo.Repository.WikiPath())
+		wikiRepo, err := gitrepo.OpenWikiRepository(ctx, ctx.Repo.Repository)
 		if err != nil {
 			ctx.ServerError("OpenRepository", err)
 			return

routers/web/repo/compare.go

@@ -28,6 +28,7 @@ import (
 	"code.gitea.io/gitea/modules/context"
 	csv_module "code.gitea.io/gitea/modules/csv"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
@@ -408,7 +409,7 @@ func ParseCompareInfo(ctx *context.Context) *CompareInfo {
 		ci.HeadRepo = ctx.Repo.Repository
 		ci.HeadGitRepo = ctx.Repo.GitRepo
 	} else if has {
-		ci.HeadGitRepo, err = git.OpenRepository(ctx, ci.HeadRepo.RepoPath())
+		ci.HeadGitRepo, err = gitrepo.OpenRepository(ctx, ci.HeadRepo)
 		if err != nil {
 			ctx.ServerError("OpenRepository", err)
 			return nil
@@ -688,7 +689,7 @@ func PrepareCompareDiff(
 }
 
 func getBranchesAndTagsForRepo(ctx gocontext.Context, repo *repo_model.Repository) (branches, tags []string, err error) {
-	gitRepo, err := git.OpenRepository(ctx, repo.RepoPath())
+	gitRepo, err := gitrepo.OpenRepository(ctx, repo)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -876,7 +877,7 @@ func ExcerptBlob(ctx *context.Context) {
 	gitRepo := ctx.Repo.GitRepo
 	if ctx.FormBool("wiki") {
 		var err error
-		gitRepo, err = git.OpenRepository(ctx, ctx.Repo.Repository.WikiPath())
+		gitRepo, err = gitrepo.OpenWikiRepository(ctx, ctx.Repo.Repository)
 		if err != nil {
 			ctx.ServerError("OpenRepository", err)
 			return

routers/web/repo/editor_test.go

@@ -9,6 +9,7 @@ import (
 	"code.gitea.io/gitea/models/unittest"
 	"code.gitea.io/gitea/modules/contexttest"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -66,7 +67,7 @@ func TestGetClosestParentWithFiles(t *testing.T) {
 
 	repo := ctx.Repo.Repository
 	branch := repo.DefaultBranch
-	gitRepo, _ := git.OpenRepository(git.DefaultContext, repo.RepoPath())
+	gitRepo, _ := gitrepo.OpenRepository(git.DefaultContext, repo)
 	defer gitRepo.Close()
 	commit, _ := gitRepo.GetBranchCommit(branch)
 	var expectedTreePath string // Should return the root dir, empty string, since there are no subdirs in this repo

routers/web/repo/pull.go

@@ -29,6 +29,7 @@ import (
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
 	issue_template "code.gitea.io/gitea/modules/issue/template"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -530,7 +531,7 @@ func PrepareViewPullInfo(ctx *context.Context, issue *issues_model.Issue) *git.C
 	if pull.BaseRepoID == ctx.Repo.Repository.ID && ctx.Repo.GitRepo != nil {
 		baseGitRepo = ctx.Repo.GitRepo
 	} else {
-		baseGitRepo, err := git.OpenRepository(ctx, pull.BaseRepo.RepoPath())
+		baseGitRepo, err := gitrepo.OpenRepository(ctx, pull.BaseRepo)
 		if err != nil {
 			ctx.ServerError("OpenRepository", err)
 			return nil
@@ -582,7 +583,7 @@ func PrepareViewPullInfo(ctx *context.Context, issue *issues_model.Issue) *git.C
 	var headBranchSha string
 	// HeadRepo may be missing
 	if pull.HeadRepo != nil {
-		headGitRepo, err := git.OpenRepository(ctx, pull.HeadRepo.RepoPath())
+		headGitRepo, err := gitrepo.OpenRepository(ctx, pull.HeadRepo)
 		if err != nil {
 			ctx.ServerError("OpenRepository", err)
 			return nil
@@ -1314,9 +1315,9 @@ func MergePullRequest(ctx *context.Context) {
 		if ctx.Repo != nil && ctx.Repo.Repository != nil && pr.HeadRepoID == ctx.Repo.Repository.ID && ctx.Repo.GitRepo != nil {
 			headRepo = ctx.Repo.GitRepo
 		} else {
-			headRepo, err = git.OpenRepository(ctx, pr.HeadRepo.RepoPath())
+			headRepo, err = gitrepo.OpenRepository(ctx, pr.HeadRepo)
 			if err != nil {
-				ctx.ServerError(fmt.Sprintf("OpenRepository[%s]", pr.HeadRepo.RepoPath()), err)
+				ctx.ServerError(fmt.Sprintf("OpenRepository[%s]", pr.HeadRepo.FullName()), err)
 				return
 			}
 			defer headRepo.Close()
@@ -1537,9 +1538,9 @@ func CleanUpPullRequest(ctx *context.Context) {
 		gitBaseRepo = ctx.Repo.GitRepo
 	} else {
 		// If not just open it
-		gitBaseRepo, err = git.OpenRepository(ctx, pr.BaseRepo.RepoPath())
+		gitBaseRepo, err = gitrepo.OpenRepository(ctx, pr.BaseRepo)
 		if err != nil {
-			ctx.ServerError(fmt.Sprintf("OpenRepository[%s]", pr.BaseRepo.RepoPath()), err)
+			ctx.ServerError(fmt.Sprintf("OpenRepository[%s]", pr.BaseRepo.FullName()), err)
 			return
 		}
 		defer gitBaseRepo.Close()
@@ -1552,9 +1553,9 @@ func CleanUpPullRequest(ctx *context.Context) {
 		gitRepo = ctx.Repo.GitRepo
 	} else if pr.BaseRepoID != pr.HeadRepoID {
 		// Otherwise just load it up
-		gitRepo, err = git.OpenRepository(ctx, pr.HeadRepo.RepoPath())
+		gitRepo, err = gitrepo.OpenRepository(ctx, pr.HeadRepo)
 		if err != nil {
-			ctx.ServerError(fmt.Sprintf("OpenRepository[%s]", pr.HeadRepo.RepoPath()), err)
+			ctx.ServerError(fmt.Sprintf("OpenRepository[%s]", pr.HeadRepo.FullName()), err)
 			return
 		}
 		defer gitRepo.Close()

routers/web/repo/wiki.go

@@ -20,6 +20,7 @@ import (
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
@@ -92,7 +93,7 @@ func findEntryForFile(commit *git.Commit, target string) (*git.TreeEntry, error)
 }
 
 func findWikiRepoCommit(ctx *context.Context) (*git.Repository, *git.Commit, error) {
-	wikiRepo, err := git.OpenRepository(ctx, ctx.Repo.Repository.WikiPath())
+	wikiRepo, err := gitrepo.OpenWikiRepository(ctx, ctx.Repo.Repository)
 	if err != nil {
 		ctx.ServerError("OpenRepository", err)
 		return nil, nil, err

routers/web/repo/wiki_test.go

@@ -13,6 +13,7 @@ import (
 	"code.gitea.io/gitea/models/unittest"
 	"code.gitea.io/gitea/modules/contexttest"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/services/forms"
 	wiki_service "code.gitea.io/gitea/services/wiki"
@@ -26,7 +27,7 @@ const (
 )
 
 func wikiEntry(t *testing.T, repo *repo_model.Repository, wikiName wiki_service.WebPath) *git.TreeEntry {
-	wikiRepo, err := git.OpenRepository(git.DefaultContext, repo.WikiPath())
+	wikiRepo, err := gitrepo.OpenWikiRepository(git.DefaultContext, repo)
 	assert.NoError(t, err)
 	defer wikiRepo.Close()
 	commit, err := wikiRepo.GetBranchCommit("master")