tea pr checkout: fetch via ssh if available (#192)

improved logging

try to use local branch before creating pulls/<PR>

useful for checking out your own PRs

reorder imports

refactor pulls checkout

isolated "gitea API to local git cfg" aspect

work around go-git limitation

As we cant manage multiple remote URLs properly, we just set the correct
URL protocol ahead of time.

This logic won't apply for already existing HTTPS remotes, these
should be deleted before using `tea pr checkout`.

use SSH if user has key in gitea

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Norwin Roosen <git@nroo.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/192
Reviewed-by: 6543 <6543@noreply.gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-Authored-By: Norwin <noerw@noreply.gitea.io>
Co-Committed-By: Norwin <noerw@noreply.gitea.io>

cmd/pulls/checkout.go

@@ -13,6 +13,7 @@ import (
 	local_git "code.gitea.io/tea/modules/git"
 	"code.gitea.io/tea/modules/utils"
 
+	"code.gitea.io/sdk/gitea"
 	"github.com/go-git/go-git/v5"
 	"github.com/urfave/cli/v2"
 )
@@ -32,40 +33,33 @@ func runPullsCheckout(ctx *cli.Context) error {
 	if ctx.Args().Len() != 1 {
 		log.Fatal("Must specify a PR index")
 	}
-
-	// fetch PR source-repo & -branch from gitea
 	idx, err := utils.ArgToIndex(ctx.Args().First())
 	if err != nil {
 		return err
 	}
-	pr, _, err := login.Client().GetPullRequest(owner, repo, idx)
+
+	localRepo, err := local_git.RepoForWorkdir()
 	if err != nil {
 		return err
 	}
-	remoteURL := pr.Head.Repository.CloneURL
-	remoteBranchName := pr.Head.Ref
 
-	// open local git repo
+	localBranchName, remoteBranchName, newRemoteName, remoteURL, err :=
-	localRepo, err := local_git.RepoForWorkdir()
+		gitConfigForPR(localRepo, login, owner, repo, idx)
 	if err != nil {
-		return nil
+		return err
 	}
 
 	// verify related remote is in local repo, otherwise add it
-	newRemoteName := fmt.Sprintf("pulls/%v", pr.Head.Repository.Owner.UserName)
 	localRemote, err := localRepo.GetOrCreateRemote(remoteURL, newRemoteName)
 	if err != nil {
 		return err
 	}
-
 	localRemoteName := localRemote.Config().Name
-	localBranchName := fmt.Sprintf("pulls/%v-%v", idx, remoteBranchName)
 
-	// fetch remote
+	// get auth & fetch remote
 	fmt.Printf("Fetching PR %v (head %s:%s) from remote '%s'\n",
 		idx, remoteURL, remoteBranchName, localRemoteName)
-
+	url, err := local_git.ParseURL(remoteURL)
-	url, err := local_git.ParseURL(localRemote.Config().URLs[0])
 	if err != nil {
 		return err
 	}
@@ -73,7 +67,6 @@ func runPullsCheckout(ctx *cli.Context) error {
 	if err != nil {
 		return err
 	}
-
 	err = localRemote.Fetch(&git.FetchOptions{Auth: auth})
 	if err == git.NoErrAlreadyUpToDate {
 		fmt.Println(err)
@@ -85,13 +78,38 @@ func runPullsCheckout(ctx *cli.Context) error {
 	fmt.Printf("Creating branch '%s'\n", localBranchName)
 	err = localRepo.TeaCreateBranch(localBranchName, remoteBranchName, localRemoteName)
 	if err == git.ErrBranchExists {
-		fmt.Println(err)
+		fmt.Println("There may be changes since you last checked out, run `git pull` to get them.")
 	} else if err != nil {
 		return err
 	}
 
-	fmt.Printf("Checking out PR %v\n", idx)
+	return localRepo.TeaCheckout(localBranchName)
-	err = localRepo.TeaCheckout(localBranchName)
+}
-
+
-	return err
+func gitConfigForPR(repo *local_git.TeaRepo, login *config.Login, owner, repoName string, idx int64) (localBranch, remoteBranch, remoteName, remoteURL string, err error) {
+	// fetch PR source-repo & -branch from gitea
+	pr, _, err := login.Client().GetPullRequest(owner, repoName, idx)
+	if err != nil {
+		return
+	}
+
+	// test if we can pull via SSH, and configure git remote accordingly
+	remoteURL = pr.Head.Repository.CloneURL
+	keys, _, err := login.Client().ListMyPublicKeys(gitea.ListPublicKeysOptions{})
+	if err != nil {
+		return
+	}
+	if len(keys) != 0 {
+		remoteURL = pr.Head.Repository.SSHURL
+	}
+
+	// try to find a matching existing branch, otherwise return branch in pulls/ namespace
+	localBranch = fmt.Sprintf("pulls/%v-%v", idx, pr.Head.Ref)
+	if b, _ := repo.TeaFindBranchBySha(pr.Head.Sha, remoteURL); b != nil {
+		localBranch = b.Name
+	}
+
+	remoteBranch = pr.Head.Ref
+	remoteName = fmt.Sprintf("pulls/%v", pr.Head.Repository.Owner.UserName)
+	return
 }