github.com/zaquestion/lab@v0.25.1/cmd/mr_checkout.go

package cmd

import (
	"fmt"

	"github.com/MakeNowJust/heredoc/v2"
	"github.com/rsteube/carapace"
	"github.com/spf13/cobra"
	"github.com/zaquestion/lab/internal/action"
	"github.com/zaquestion/lab/internal/git"
	lab "github.com/zaquestion/lab/internal/gitlab"
)

// mrCheckoutConfig holds configuration values for calls to lab mr checkout
type mrCheckoutConfig struct {
	branch string
	force  bool
	track  bool
}

var (
	mrCheckoutCfg mrCheckoutConfig
)

// listCmd represents the list command
var checkoutCmd = &cobra.Command{
	Use:     "checkout [remote] [<MR id or branch>]",
	Aliases: []string{"co"},
	Short:   "Checkout an open merge request",
	Long: heredoc.Doc(`
		Checkout an open merge request using the MR's source branch name as
		local branch name; this behavior can be changed using --branch
		option.`),
	Args: cobra.RangeArgs(1, 2),
	Example: heredoc.Doc(`
		lab mr checkout origin 10
		lab mr checkout upstream -b a_branch_name
		lab mr checkout a_remote -f
		lab mr checkout upstream --https
		lab mr checkout upstream -t`),
	PersistentPreRun: labPersistentPreRun,
	Run: func(cmd *cobra.Command, args []string) {
		rn, mrID, err := parseArgsRemoteAndID(args)
		if err != nil {
			log.Fatal(err)
		}

		targetRemote := defaultRemote
		if len(args) == 2 {
			// parseArgs above already validated this is a remote
			targetRemote = args[0]
		}

		mr, err := lab.MRGet(rn, int(mrID))
		if err != nil {
			log.Fatal(err)
		}

		// If the config does not specify a branch, use the mr source branch name
		if mrCheckoutCfg.branch == "" {
			mrCheckoutCfg.branch = mr.SourceBranch
		}

		err = git.New("show-ref", "--verify", "--quiet", "refs/heads/"+mrCheckoutCfg.branch).Run()
		if err == nil {
			if mrCheckoutCfg.force {
				err = git.New("branch", "-D", mrCheckoutCfg.branch).Run()
				if err != nil {
					log.Fatal(err)
				}
			} else {
				log.Fatalf("branch %s already exists", mrCheckoutCfg.branch)
			}
		}

		// By default, fetch to configured branch
		fetchToRef := mrCheckoutCfg.branch

		// If track, make sure we have a remote for the mr author and then set
		// the fetchToRef to the mr author/sourceBranch
		if mrCheckoutCfg.track {
			// Check if remote already exists
			project, err := lab.GetProject(mr.SourceProjectID)
			if err != nil {
				log.Fatal(err)
			}

			remotes, err := git.Remotes()
			if err != nil {
				log.Fatal(err)
			}

			remoteName := ""
			for _, remote := range remotes {
				path, err := git.PathWithNamespace(remote)
				if err != nil {
					continue
				}
				if path == project.PathWithNamespace {
					remoteName = remote
					break
				}
			}

			if remoteName == "" {
				remoteName = mr.Author.Username
				urlToRepo := labURLToRepo(project)
				err := git.RemoteAdd(remoteName, urlToRepo, ".")
				if err != nil {
					log.Fatal(err)
				}
			}

			trackRef := fmt.Sprintf("refs/remotes/%s/%s", remoteName, mr.SourceBranch)
			err = git.New("show-ref", "--verify", "--quiet", trackRef).Run()
			if err == nil {
				if mrCheckoutCfg.force {
					err = git.New("update-ref", "-d", trackRef).Run()
					if err != nil {
						log.Fatal(err)
					}
				} else {
					log.Fatalf("remote reference %s already exists", trackRef)
				}
			}

			fetchToRef = trackRef
		}

		// https://docs.gitlab.com/ee/user/project/merge_requests/reviews/#checkout-merge-requests-locally-through-the-head-ref
		mrRef := fmt.Sprintf("refs/merge-requests/%d/head", mrID)
		fetchRefSpec := fmt.Sprintf("%s:%s", mrRef, fetchToRef)
		err = git.New("fetch", targetRemote, fetchRefSpec).Run()
		if err != nil {
			log.Fatal(err)
		}

		if mrCheckoutCfg.track {
			// Create configured branch with tracking from fetchToRef
			// git branch --flags <branchname> [<start-point>]
			err = git.New("branch", "--track", mrCheckoutCfg.branch, fetchToRef).Run()
			if err != nil {
				log.Fatal(err)
			}
		}

		err = git.New("checkout", mrCheckoutCfg.branch).Run()
		if err != nil {
			log.Fatal(err)
		}
	},
}

func init() {
	checkoutCmd.Flags().StringVarP(&mrCheckoutCfg.branch, "branch", "b", "", "checkout merge request with <branch> name")
	checkoutCmd.Flags().BoolVarP(&mrCheckoutCfg.track, "track", "t", false, "set branch to track remote branch, adds remote if needed")
	// useHTTP is defined in "project_create.go"
	checkoutCmd.Flags().BoolVar(&useHTTP, "http", false, "checkout using HTTP protocol instead of SSH")
	checkoutCmd.Flags().BoolVarP(&mrCheckoutCfg.force, "force", "f", false, "force branch and remote reference override")
	mrCmd.AddCommand(checkoutCmd)
	carapace.Gen(checkoutCmd).PositionalCompletion(
		carapace.ActionCallback(func(c carapace.Context) carapace.Action {
			c.Args = []string{"origin"}
			return action.MergeRequests(mrList).Invoke(c).ToA()
		}),
	)
}