1 files changed, 320 insertions, 0 deletions

diff --git a/services/pull/merge.go b/services/pull/merge.go
new file mode 100644
index 0000000000..6150c1518e
--- /dev/null
+++ b/services/pull/merge.go
@@ -0,0 +1,320 @@
+// 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 pull
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/cache"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+// Merge merges pull request to base repository.
+// FIXME: add repoWorkingPull make sure two merges does not happen at same time.
+func Merge(pr *models.PullRequest, doer *models.User, baseGitRepo *git.Repository, mergeStyle models.MergeStyle, message string) (err error) {
+	if err = pr.GetHeadRepo(); err != nil {
+		return fmt.Errorf("GetHeadRepo: %v", err)
+	} else if err = pr.GetBaseRepo(); err != nil {
+		return fmt.Errorf("GetBaseRepo: %v", err)
+	}
+
+	prUnit, err := pr.BaseRepo.GetUnit(models.UnitTypePullRequests)
+	if err != nil {
+		return err
+	}
+	prConfig := prUnit.PullRequestsConfig()
+
+	if err := pr.CheckUserAllowedToMerge(doer); err != nil {
+		return fmt.Errorf("CheckUserAllowedToMerge: %v", err)
+	}
+
+	// Check if merge style is correct and allowed
+	if !prConfig.IsMergeStyleAllowed(mergeStyle) {
+		return models.ErrInvalidMergeStyle{ID: pr.BaseRepo.ID, Style: mergeStyle}
+	}
+
+	defer func() {
+		go models.AddTestPullRequestTask(doer, pr.BaseRepo.ID, pr.BaseBranch, false)
+	}()
+
+	// Clone base repo.
+	tmpBasePath, err := models.CreateTemporaryPath("merge")
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		if err := models.RemoveTemporaryPath(tmpBasePath); err != nil {
+			log.Error("Merge: RemoveTemporaryPath: %s", err)
+		}
+	}()
+
+	headRepoPath := models.RepoPath(pr.HeadUserName, pr.HeadRepo.Name)
+
+	if err := git.Clone(baseGitRepo.Path, tmpBasePath, git.CloneRepoOptions{
+		Shared:     true,
+		NoCheckout: true,
+		Branch:     pr.BaseBranch,
+	}); err != nil {
+		return fmt.Errorf("git clone: %v", err)
+	}
+
+	remoteRepoName := "head_repo"
+
+	// Add head repo remote.
+	addCacheRepo := func(staging, cache string) error {
+		p := filepath.Join(staging, ".git", "objects", "info", "alternates")
+		f, err := os.OpenFile(p, os.O_APPEND|os.O_WRONLY, 0600)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		data := filepath.Join(cache, "objects")
+		if _, err := fmt.Fprintln(f, data); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	if err := addCacheRepo(tmpBasePath, headRepoPath); err != nil {
+		return fmt.Errorf("addCacheRepo [%s -> %s]: %v", headRepoPath, tmpBasePath, err)
+	}
+
+	var errbuf strings.Builder
+	if err := git.NewCommand("remote", "add", remoteRepoName, headRepoPath).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git remote add [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+	}
+
+	// Fetch head branch
+	if err := git.NewCommand("fetch", remoteRepoName, fmt.Sprintf("%s:refs/remotes/%s/%s", pr.HeadBranch, remoteRepoName, pr.HeadBranch)).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git fetch [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+	}
+
+	trackingBranch := path.Join(remoteRepoName, pr.HeadBranch)
+	stagingBranch := fmt.Sprintf("%s_%s", remoteRepoName, pr.HeadBranch)
+
+	// Enable sparse-checkout
+	sparseCheckoutList, err := getDiffTree(tmpBasePath, pr.BaseBranch, trackingBranch)
+	if err != nil {
+		return fmt.Errorf("getDiffTree: %v", err)
+	}
+
+	infoPath := filepath.Join(tmpBasePath, ".git", "info")
+	if err := os.MkdirAll(infoPath, 0700); err != nil {
+		return fmt.Errorf("creating directory failed [%s]: %v", infoPath, err)
+	}
+	sparseCheckoutListPath := filepath.Join(infoPath, "sparse-checkout")
+	if err := ioutil.WriteFile(sparseCheckoutListPath, []byte(sparseCheckoutList), 0600); err != nil {
+		return fmt.Errorf("Writing sparse-checkout file to %s: %v", sparseCheckoutListPath, err)
+	}
+
+	// Switch off LFS process (set required, clean and smudge here also)
+	if err := git.NewCommand("config", "--local", "filter.lfs.process", "").RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git config [filter.lfs.process -> <> ]: %v", errbuf.String())
+	}
+	if err := git.NewCommand("config", "--local", "filter.lfs.required", "false").RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git config [filter.lfs.required -> <false> ]: %v", errbuf.String())
+	}
+	if err := git.NewCommand("config", "--local", "filter.lfs.clean", "").RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git config [filter.lfs.clean -> <> ]: %v", errbuf.String())
+	}
+	if err := git.NewCommand("config", "--local", "filter.lfs.smudge", "").RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git config [filter.lfs.smudge -> <> ]: %v", errbuf.String())
+	}
+
+	if err := git.NewCommand("config", "--local", "core.sparseCheckout", "true").RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git config [core.sparsecheckout -> true]: %v", errbuf.String())
+	}
+
+	// Read base branch index
+	if err := git.NewCommand("read-tree", "HEAD").RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git read-tree HEAD: %s", errbuf.String())
+	}
+
+	// Merge commits.
+	switch mergeStyle {
+	case models.MergeStyleMerge:
+		if err := git.NewCommand("merge", "--no-ff", "--no-commit", trackingBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git merge --no-ff --no-commit [%s]: %v - %s", tmpBasePath, err, errbuf.String())
+		}
+
+		sig := doer.NewGitSig()
+		if err := git.NewCommand("commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email), "-m", message).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git commit [%s]: %v - %s", tmpBasePath, err, errbuf.String())
+		}
+	case models.MergeStyleRebase:
+		// Checkout head branch
+		if err := git.NewCommand("checkout", "-b", stagingBranch, trackingBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git checkout: %s", errbuf.String())
+		}
+		// Rebase before merging
+		if err := git.NewCommand("rebase", "-q", pr.BaseBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git rebase [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+		}
+		// Checkout base branch again
+		if err := git.NewCommand("checkout", pr.BaseBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git checkout: %s", errbuf.String())
+		}
+		// Merge fast forward
+		if err := git.NewCommand("merge", "--ff-only", "-q", stagingBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git merge --ff-only [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+		}
+	case models.MergeStyleRebaseMerge:
+		// Checkout head branch
+		if err := git.NewCommand("checkout", "-b", stagingBranch, trackingBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git checkout: %s", errbuf.String())
+		}
+		// Rebase before merging
+		if err := git.NewCommand("rebase", "-q", pr.BaseBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git rebase [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+		}
+		// Checkout base branch again
+		if err := git.NewCommand("checkout", pr.BaseBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git checkout: %s", errbuf.String())
+		}
+		// Prepare merge with commit
+		if err := git.NewCommand("merge", "--no-ff", "--no-commit", "-q", stagingBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git merge --no-ff [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+		}
+
+		// Set custom message and author and create merge commit
+		sig := doer.NewGitSig()
+		if err := git.NewCommand("commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email), "-m", message).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git commit [%s]: %v - %s", tmpBasePath, err, errbuf.String())
+		}
+
+	case models.MergeStyleSquash:
+		// Merge with squash
+		if err := git.NewCommand("merge", "-q", "--squash", trackingBranch).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git merge --squash [%s -> %s]: %s", headRepoPath, tmpBasePath, errbuf.String())
+		}
+		sig := pr.Issue.Poster.NewGitSig()
+		if err := git.NewCommand("commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email), "-m", message).RunInDirPipeline(tmpBasePath, nil, &errbuf); err != nil {
+			return fmt.Errorf("git commit [%s]: %v - %s", tmpBasePath, err, errbuf.String())
+		}
+	default:
+		return models.ErrInvalidMergeStyle{ID: pr.BaseRepo.ID, Style: mergeStyle}
+	}
+
+	// OK we should cache our current head and origin/headbranch
+	mergeHeadSHA, err := git.GetFullCommitID(tmpBasePath, "HEAD")
+	if err != nil {
+		return fmt.Errorf("Failed to get full commit id for HEAD: %v", err)
+	}
+	mergeBaseSHA, err := git.GetFullCommitID(tmpBasePath, "origin/"+pr.BaseBranch)
+	if err != nil {
+		return fmt.Errorf("Failed to get full commit id for origin/%s: %v", pr.BaseBranch, err)
+	}
+
+	// Now it's questionable about where this should go - either after or before the push
+	// I think in the interests of data safety - failures to push to the lfs should prevent
+	// the merge as you can always remerge.
+	if setting.LFS.StartServer {
+		if err := LFSPush(tmpBasePath, mergeHeadSHA, mergeBaseSHA, pr); err != nil {
+			return err
+		}
+	}
+
+	headUser, err := models.GetUserByName(pr.HeadUserName)
+	if err != nil {
+		if !models.IsErrUserNotExist(err) {
+			log.Error("Can't find user: %s for head repository - %v", pr.HeadUserName, err)
+			return err
+		}
+		log.Error("Can't find user: %s for head repository - defaulting to doer: %s - %v", pr.HeadUserName, doer.Name, err)
+		headUser = doer
+	}
+
+	env := models.FullPushingEnvironment(
+		headUser,
+		doer,
+		pr.BaseRepo,
+		pr.BaseRepo.Name,
+		pr.ID,
+	)
+
+	// Push back to upstream.
+	if err := git.NewCommand("push", "origin", pr.BaseBranch).RunInDirTimeoutEnvPipeline(env, -1, tmpBasePath, nil, &errbuf); err != nil {
+		return fmt.Errorf("git push: %s", errbuf.String())
+	}
+
+	pr.MergedCommitID, err = baseGitRepo.GetBranchCommitID(pr.BaseBranch)
+	if err != nil {
+		return fmt.Errorf("GetBranchCommit: %v", err)
+	}
+
+	pr.MergedUnix = timeutil.TimeStampNow()
+	pr.Merger = doer
+	pr.MergerID = doer.ID
+
+	if err = pr.SetMerged(); err != nil {
+		log.Error("setMerged [%d]: %v", pr.ID, err)
+	}
+
+	if err = models.MergePullRequestAction(doer, pr.Issue.Repo, pr.Issue); err != nil {
+		log.Error("MergePullRequestAction [%d]: %v", pr.ID, err)
+	}
+
+	// Reset cached commit count
+	cache.Remove(pr.Issue.Repo.GetCommitsCountCacheKey(pr.BaseBranch, true))
+
+	// Reload pull request information.
+	if err = pr.LoadAttributes(); err != nil {
+		log.Error("LoadAttributes: %v", err)
+		return nil
+	}
+
+	mode, _ := models.AccessLevel(doer, pr.Issue.Repo)
+	if err = models.PrepareWebhooks(pr.Issue.Repo, models.HookEventPullRequest, &api.PullRequestPayload{
+		Action:      api.HookIssueClosed,
+		Index:       pr.Index,
+		PullRequest: pr.APIFormat(),
+		Repository:  pr.Issue.Repo.APIFormat(mode),
+		Sender:      doer.APIFormat(),
+	}); err != nil {
+		log.Error("PrepareWebhooks: %v", err)
+	} else {
+		go models.HookQueue.Add(pr.Issue.Repo.ID)
+	}
+
+	return nil
+}
+
+func getDiffTree(repoPath, baseBranch, headBranch string) (string, error) {
+	getDiffTreeFromBranch := func(repoPath, baseBranch, headBranch string) (string, error) {
+		var outbuf, errbuf strings.Builder
+		// Compute the diff-tree for sparse-checkout
+		if err := git.NewCommand("diff-tree", "--no-commit-id", "--name-only", "-r", "--root", baseBranch, headBranch, "--").RunInDirPipeline(repoPath, &outbuf, &errbuf); err != nil {
+			return "", fmt.Errorf("git diff-tree [%s base:%s head:%s]: %s", repoPath, baseBranch, headBranch, errbuf.String())
+		}
+		return outbuf.String(), nil
+	}
+
+	list, err := getDiffTreeFromBranch(repoPath, baseBranch, headBranch)
+	if err != nil {
+		return "", err
+	}
+
+	// Prefixing '/' for each entry, otherwise all files with the same name in subdirectories would be matched.
+	out := bytes.Buffer{}
+	scanner := bufio.NewScanner(strings.NewReader(list))
+	for scanner.Scan() {
+		fmt.Fprintf(&out, "/%s\n", scanner.Text())
+	}
+	return out.String(), nil
+}