[Refactor] move pull checkout & clean code into task module (#249)

Merge branch 'master' into refactor_checkout2task

move pull clean code into task module

fix lint

format code

unify PullCheckout() and gitConfigForPR()

move pull checkout code into task module

Co-authored-by: 6543 <6543@noreply.gitea.io>
Reviewed-on: https://gitea.com/gitea/tea/pulls/249
Reviewed-by: Norwin <noerw@noreply.gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-Authored-By: 6543 <6543@obermui.de>
Co-Committed-By: 6543 <6543@obermui.de>

modules/task/pull_checkout.go

@@ -0,0 +1,84 @@
+// Copyright 2020 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 task
+
+import (
+	"fmt"
+
+	"code.gitea.io/sdk/gitea"
+	"code.gitea.io/tea/modules/config"
+	local_git "code.gitea.io/tea/modules/git"
+
+	"github.com/go-git/go-git/v5"
+)
+
+// PullCheckout checkout current workdir to the head branch of specified pull request
+func PullCheckout(login *config.Login, repoOwner, repoName string, index int64) error {
+	client := login.Client()
+
+	localRepo, err := local_git.RepoForWorkdir()
+	if err != nil {
+		return err
+	}
+
+	// fetch PR source-localRepo & -branch from gitea
+	pr, _, err := client.GetPullRequest(repoOwner, repoName, index)
+	if err != nil {
+		return err
+	}
+
+	// test if we can pull via SSH, and configure git remote accordingly
+	remoteURL := pr.Head.Repository.CloneURL
+	keys, _, err := client.ListMyPublicKeys(gitea.ListPublicKeysOptions{})
+	if err != nil {
+		return err
+	}
+	if len(keys) != 0 {
+		remoteURL = pr.Head.Repository.SSHURL
+	}
+
+	// try to find a matching existing branch, otherwise return branch in pulls/ namespace
+	localBranchName := fmt.Sprintf("pulls/%v-%v", index, pr.Head.Ref)
+	if b, _ := localRepo.TeaFindBranchBySha(pr.Head.Sha, remoteURL); b != nil {
+		localBranchName = b.Name
+	}
+
+	newRemoteName := fmt.Sprintf("pulls/%v", pr.Head.Repository.Owner.UserName)
+
+	// verify related remote is in local repo, otherwise add it
+	localRemote, err := localRepo.GetOrCreateRemote(remoteURL, newRemoteName)
+	if err != nil {
+		return err
+	}
+	localRemoteName := localRemote.Config().Name
+
+	// get auth & fetch remote
+	fmt.Printf("Fetching PR %v (head %s:%s) from remote '%s'\n", index, remoteURL, pr.Head.Ref, localRemoteName)
+	url, err := local_git.ParseURL(remoteURL)
+	if err != nil {
+		return err
+	}
+	auth, err := local_git.GetAuthForURL(url, login.User, login.SSHKey)
+	if err != nil {
+		return err
+	}
+	err = localRemote.Fetch(&git.FetchOptions{Auth: auth})
+	if err == git.NoErrAlreadyUpToDate {
+		fmt.Println(err)
+	} else if err != nil {
+		return err
+	}
+
+	// checkout local branch
+	fmt.Printf("Creating branch '%s'\n", localBranchName)
+	err = localRepo.TeaCreateBranch(localBranchName, pr.Head.Ref, localRemoteName)
+	if err == git.ErrBranchExists {
+		fmt.Println("There may be changes since you last checked out, run `git pull` to get them.")
+	} else if err != nil {
+		return err
+	}
+
+	return localRepo.TeaCheckout(localBranchName)
+}