internal: move packages under this directory (#5836)

* Rename pkg -> internal

* Rename routes -> route

* Move route -> internal/route

* Rename models -> db

* Move db -> internal/db

* Fix route2 -> route

* Move cmd -> internal/cmd

* Bump version

1 files changed, 851 insertions, 0 deletions

diff --git a/internal/db/pull.go b/internal/db/pull.go
new file mode 100644
index 00000000..30179eb2
--- /dev/null
+++ b/internal/db/pull.go
@@ -0,0 +1,851 @@
+// Copyright 2015 The Gogs 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 db
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/unknwon/com"
+	log "gopkg.in/clog.v1"
+	"xorm.io/xorm"
+
+	"github.com/gogs/git-module"
+	api "github.com/gogs/go-gogs-client"
+
+	"gogs.io/gogs/internal/db/errors"
+	"gogs.io/gogs/internal/process"
+	"gogs.io/gogs/internal/setting"
+	"gogs.io/gogs/internal/sync"
+)
+
+var PullRequestQueue = sync.NewUniqueQueue(setting.Repository.PullRequestQueueLength)
+
+type PullRequestType int
+
+const (
+	PULL_REQUEST_GOGS PullRequestType = iota
+	PLLL_ERQUEST_GIT
+)
+
+type PullRequestStatus int
+
+const (
+	PULL_REQUEST_STATUS_CONFLICT PullRequestStatus = iota
+	PULL_REQUEST_STATUS_CHECKING
+	PULL_REQUEST_STATUS_MERGEABLE
+)
+
+// PullRequest represents relation between pull request and repositories.
+type PullRequest struct {
+	ID     int64
+	Type   PullRequestType
+	Status PullRequestStatus
+
+	IssueID int64  `xorm:"INDEX"`
+	Issue   *Issue `xorm:"-" json:"-"`
+	Index   int64
+
+	HeadRepoID   int64
+	HeadRepo     *Repository `xorm:"-" json:"-"`
+	BaseRepoID   int64
+	BaseRepo     *Repository `xorm:"-" json:"-"`
+	HeadUserName string
+	HeadBranch   string
+	BaseBranch   string
+	MergeBase    string `xorm:"VARCHAR(40)"`
+
+	HasMerged      bool
+	MergedCommitID string `xorm:"VARCHAR(40)"`
+	MergerID       int64
+	Merger         *User     `xorm:"-" json:"-"`
+	Merged         time.Time `xorm:"-" json:"-"`
+	MergedUnix     int64
+}
+
+func (pr *PullRequest) BeforeUpdate() {
+	pr.MergedUnix = pr.Merged.Unix()
+}
+
+// Note: don't try to get Issue because will end up recursive querying.
+func (pr *PullRequest) AfterSet(colName string, _ xorm.Cell) {
+	switch colName {
+	case "merged_unix":
+		if !pr.HasMerged {
+			return
+		}
+
+		pr.Merged = time.Unix(pr.MergedUnix, 0).Local()
+	}
+}
+
+// Note: don't try to get Issue because will end up recursive querying.
+func (pr *PullRequest) loadAttributes(e Engine) (err error) {
+	if pr.HeadRepo == nil {
+		pr.HeadRepo, err = getRepositoryByID(e, pr.HeadRepoID)
+		if err != nil && !errors.IsRepoNotExist(err) {
+			return fmt.Errorf("getRepositoryByID.(HeadRepo) [%d]: %v", pr.HeadRepoID, err)
+		}
+	}
+
+	if pr.BaseRepo == nil {
+		pr.BaseRepo, err = getRepositoryByID(e, pr.BaseRepoID)
+		if err != nil {
+			return fmt.Errorf("getRepositoryByID.(BaseRepo) [%d]: %v", pr.BaseRepoID, err)
+		}
+	}
+
+	if pr.HasMerged && pr.Merger == nil {
+		pr.Merger, err = getUserByID(e, pr.MergerID)
+		if errors.IsUserNotExist(err) {
+			pr.MergerID = -1
+			pr.Merger = NewGhostUser()
+		} else if err != nil {
+			return fmt.Errorf("getUserByID [%d]: %v", pr.MergerID, err)
+		}
+	}
+
+	return nil
+}
+
+func (pr *PullRequest) LoadAttributes() error {
+	return pr.loadAttributes(x)
+}
+
+func (pr *PullRequest) LoadIssue() (err error) {
+	if pr.Issue != nil {
+		return nil
+	}
+
+	pr.Issue, err = GetIssueByID(pr.IssueID)
+	return err
+}
+
+// This method assumes following fields have been assigned with valid values:
+// Required - Issue, BaseRepo
+// Optional - HeadRepo, Merger
+func (pr *PullRequest) APIFormat() *api.PullRequest {
+	// In case of head repo has been deleted.
+	var apiHeadRepo *api.Repository
+	if pr.HeadRepo == nil {
+		apiHeadRepo = &api.Repository{
+			Name: "deleted",
+		}
+	} else {
+		apiHeadRepo = pr.HeadRepo.APIFormat(nil)
+	}
+
+	apiIssue := pr.Issue.APIFormat()
+	apiPullRequest := &api.PullRequest{
+		ID:         pr.ID,
+		Index:      pr.Index,
+		Poster:     apiIssue.Poster,
+		Title:      apiIssue.Title,
+		Body:       apiIssue.Body,
+		Labels:     apiIssue.Labels,
+		Milestone:  apiIssue.Milestone,
+		Assignee:   apiIssue.Assignee,
+		State:      apiIssue.State,
+		Comments:   apiIssue.Comments,
+		HeadBranch: pr.HeadBranch,
+		HeadRepo:   apiHeadRepo,
+		BaseBranch: pr.BaseBranch,
+		BaseRepo:   pr.BaseRepo.APIFormat(nil),
+		HTMLURL:    pr.Issue.HTMLURL(),
+		HasMerged:  pr.HasMerged,
+	}
+
+	if pr.Status != PULL_REQUEST_STATUS_CHECKING {
+		mergeable := pr.Status != PULL_REQUEST_STATUS_CONFLICT
+		apiPullRequest.Mergeable = &mergeable
+	}
+	if pr.HasMerged {
+		apiPullRequest.Merged = &pr.Merged
+		apiPullRequest.MergedCommitID = &pr.MergedCommitID
+		apiPullRequest.MergedBy = pr.Merger.APIFormat()
+	}
+
+	return apiPullRequest
+}
+
+// IsChecking returns true if this pull request is still checking conflict.
+func (pr *PullRequest) IsChecking() bool {
+	return pr.Status == PULL_REQUEST_STATUS_CHECKING
+}
+
+// CanAutoMerge returns true if this pull request can be merged automatically.
+func (pr *PullRequest) CanAutoMerge() bool {
+	return pr.Status == PULL_REQUEST_STATUS_MERGEABLE
+}
+
+// MergeStyle represents the approach to merge commits into base branch.
+type MergeStyle string
+
+const (
+	MERGE_STYLE_REGULAR MergeStyle = "create_merge_commit"
+	MERGE_STYLE_REBASE  MergeStyle = "rebase_before_merging"
+)
+
+// Merge merges pull request to base repository.
+// FIXME: add repoWorkingPull make sure two merges does not happen at same time.
+func (pr *PullRequest) Merge(doer *User, baseGitRepo *git.Repository, mergeStyle MergeStyle, commitDescription string) (err error) {
+	defer func() {
+		go HookQueue.Add(pr.BaseRepo.ID)
+		go AddTestPullRequestTask(doer, pr.BaseRepo.ID, pr.BaseBranch, false)
+	}()
+
+	sess := x.NewSession()
+	defer sess.Close()
+	if err = sess.Begin(); err != nil {
+		return err
+	}
+
+	if err = pr.Issue.changeStatus(sess, doer, pr.Issue.Repo, true); err != nil {
+		return fmt.Errorf("Issue.changeStatus: %v", err)
+	}
+
+	headRepoPath := RepoPath(pr.HeadUserName, pr.HeadRepo.Name)
+	headGitRepo, err := git.OpenRepository(headRepoPath)
+	if err != nil {
+		return fmt.Errorf("OpenRepository: %v", err)
+	}
+
+	// Create temporary directory to store temporary copy of the base repository,
+	// and clean it up when operation finished regardless of succeed or not.
+	tmpBasePath := path.Join(setting.AppDataPath, "tmp/repos", com.ToStr(time.Now().Nanosecond())+".git")
+	os.MkdirAll(path.Dir(tmpBasePath), os.ModePerm)
+	defer os.RemoveAll(path.Dir(tmpBasePath))
+
+	// Clone the base repository to the defined temporary directory,
+	// and checks out to base branch directly.
+	var stderr string
+	if _, stderr, err = process.ExecTimeout(5*time.Minute,
+		fmt.Sprintf("PullRequest.Merge (git clone): %s", tmpBasePath),
+		"git", "clone", "-b", pr.BaseBranch, baseGitRepo.Path, tmpBasePath); err != nil {
+		return fmt.Errorf("git clone: %s", stderr)
+	}
+
+	// Add remote which points to the head repository.
+	if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+		fmt.Sprintf("PullRequest.Merge (git remote add): %s", tmpBasePath),
+		"git", "remote", "add", "head_repo", headRepoPath); err != nil {
+		return fmt.Errorf("git remote add [%s -> %s]: %s", headRepoPath, tmpBasePath, stderr)
+	}
+
+	// Fetch information from head repository to the temporary copy.
+	if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+		fmt.Sprintf("PullRequest.Merge (git fetch): %s", tmpBasePath),
+		"git", "fetch", "head_repo"); err != nil {
+		return fmt.Errorf("git fetch [%s -> %s]: %s", headRepoPath, tmpBasePath, stderr)
+	}
+
+	remoteHeadBranch := "head_repo/" + pr.HeadBranch
+
+	// Check if merge style is allowed, reset to default style if not
+	if mergeStyle == MERGE_STYLE_REBASE && !pr.BaseRepo.PullsAllowRebase {
+		mergeStyle = MERGE_STYLE_REGULAR
+	}
+
+	switch mergeStyle {
+	case MERGE_STYLE_REGULAR: // Create merge commit
+
+		// Merge changes from head branch.
+		if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+			fmt.Sprintf("PullRequest.Merge (git merge --no-ff --no-commit): %s", tmpBasePath),
+			"git", "merge", "--no-ff", "--no-commit", remoteHeadBranch); err != nil {
+			return fmt.Errorf("git merge --no-ff --no-commit [%s]: %v - %s", tmpBasePath, err, stderr)
+		}
+
+		// Create a merge commit for the base branch.
+		sig := doer.NewGitSig()
+		if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+			fmt.Sprintf("PullRequest.Merge (git merge): %s", tmpBasePath),
+			"git", "commit", fmt.Sprintf("--author='%s <%s>'", sig.Name, sig.Email),
+			"-m", fmt.Sprintf("Merge branch '%s' of %s/%s into %s", pr.HeadBranch, pr.HeadUserName, pr.HeadRepo.Name, pr.BaseBranch),
+			"-m", commitDescription); err != nil {
+			return fmt.Errorf("git commit [%s]: %v - %s", tmpBasePath, err, stderr)
+		}
+
+	case MERGE_STYLE_REBASE: // Rebase before merging
+
+		// Rebase head branch based on base branch, this creates a non-branch commit state.
+		if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+			fmt.Sprintf("PullRequest.Merge (git rebase): %s", tmpBasePath),
+			"git", "rebase", "--quiet", pr.BaseBranch, remoteHeadBranch); err != nil {
+			return fmt.Errorf("git rebase [%s on %s]: %s", remoteHeadBranch, pr.BaseBranch, stderr)
+		}
+
+		// Name non-branch commit state to a new temporary branch in order to save changes.
+		tmpBranch := com.ToStr(time.Now().UnixNano(), 10)
+		if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+			fmt.Sprintf("PullRequest.Merge (git checkout): %s", tmpBasePath),
+			"git", "checkout", "-b", tmpBranch); err != nil {
+			return fmt.Errorf("git checkout '%s': %s", tmpBranch, stderr)
+		}
+
+		// Check out the base branch to be operated on.
+		if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+			fmt.Sprintf("PullRequest.Merge (git checkout): %s", tmpBasePath),
+			"git", "checkout", pr.BaseBranch); err != nil {
+			return fmt.Errorf("git checkout '%s': %s", pr.BaseBranch, stderr)
+		}
+
+		// Merge changes from temporary branch to the base branch.
+		if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+			fmt.Sprintf("PullRequest.Merge (git merge): %s", tmpBasePath),
+			"git", "merge", tmpBranch); err != nil {
+			return fmt.Errorf("git merge [%s]: %v - %s", tmpBasePath, err, stderr)
+		}
+
+	default:
+		return fmt.Errorf("unknown merge style: %s", mergeStyle)
+	}
+
+	// Push changes on base branch to upstream.
+	if _, stderr, err = process.ExecDir(-1, tmpBasePath,
+		fmt.Sprintf("PullRequest.Merge (git push): %s", tmpBasePath),
+		"git", "push", baseGitRepo.Path, pr.BaseBranch); err != nil {
+		return fmt.Errorf("git push: %s", stderr)
+	}
+
+	pr.MergedCommitID, err = headGitRepo.GetBranchCommitID(pr.HeadBranch)
+	if err != nil {
+		return fmt.Errorf("GetBranchCommit: %v", err)
+	}
+
+	pr.HasMerged = true
+	pr.Merged = time.Now()
+	pr.MergerID = doer.ID
+	if _, err = sess.ID(pr.ID).AllCols().Update(pr); err != nil {
+		return fmt.Errorf("update pull request: %v", err)
+	}
+
+	if err = sess.Commit(); err != nil {
+		return fmt.Errorf("Commit: %v", err)
+	}
+
+	if err = MergePullRequestAction(doer, pr.Issue.Repo, pr.Issue); err != nil {
+		log.Error(2, "MergePullRequestAction [%d]: %v", pr.ID, err)
+	}
+
+	// Reload pull request information.
+	if err = pr.LoadAttributes(); err != nil {
+		log.Error(2, "LoadAttributes: %v", err)
+		return nil
+	}
+	if err = PrepareWebhooks(pr.Issue.Repo, HOOK_EVENT_PULL_REQUEST, &api.PullRequestPayload{
+		Action:      api.HOOK_ISSUE_CLOSED,
+		Index:       pr.Index,
+		PullRequest: pr.APIFormat(),
+		Repository:  pr.Issue.Repo.APIFormat(nil),
+		Sender:      doer.APIFormat(),
+	}); err != nil {
+		log.Error(2, "PrepareWebhooks: %v", err)
+		return nil
+	}
+
+	l, err := headGitRepo.CommitsBetweenIDs(pr.MergedCommitID, pr.MergeBase)
+	if err != nil {
+		log.Error(2, "CommitsBetweenIDs: %v", err)
+		return nil
+	}
+
+	// It is possible that head branch is not fully sync with base branch for merge commits,
+	// so we need to get latest head commit and append merge commit manully
+	// to avoid strange diff commits produced.
+	mergeCommit, err := baseGitRepo.GetBranchCommit(pr.BaseBranch)
+	if err != nil {
+		log.Error(2, "GetBranchCommit: %v", err)
+		return nil
+	}
+	if mergeStyle == MERGE_STYLE_REGULAR {
+		l.PushFront(mergeCommit)
+	}
+
+	commits, err := ListToPushCommits(l).ToApiPayloadCommits(pr.BaseRepo.RepoPath(), pr.BaseRepo.HTMLURL())
+	if err != nil {
+		log.Error(2, "ToApiPayloadCommits: %v", err)
+		return nil
+	}
+
+	p := &api.PushPayload{
+		Ref:        git.BRANCH_PREFIX + pr.BaseBranch,
+		Before:     pr.MergeBase,
+		After:      mergeCommit.ID.String(),
+		CompareURL: setting.AppURL + pr.BaseRepo.ComposeCompareURL(pr.MergeBase, pr.MergedCommitID),
+		Commits:    commits,
+		Repo:       pr.BaseRepo.APIFormat(nil),
+		Pusher:     pr.HeadRepo.MustOwner().APIFormat(),
+		Sender:     doer.APIFormat(),
+	}
+	if err = PrepareWebhooks(pr.BaseRepo, HOOK_EVENT_PUSH, p); err != nil {
+		log.Error(2, "PrepareWebhooks: %v", err)
+		return nil
+	}
+	return nil
+}
+
+// testPatch checks if patch can be merged to base repository without conflit.
+// FIXME: make a mechanism to clean up stable local copies.
+func (pr *PullRequest) testPatch() (err error) {
+	if pr.BaseRepo == nil {
+		pr.BaseRepo, err = GetRepositoryByID(pr.BaseRepoID)
+		if err != nil {
+			return fmt.Errorf("GetRepositoryByID: %v", err)
+		}
+	}
+
+	patchPath, err := pr.BaseRepo.PatchPath(pr.Index)
+	if err != nil {
+		return fmt.Errorf("BaseRepo.PatchPath: %v", err)
+	}
+
+	// Fast fail if patch does not exist, this assumes data is cruppted.
+	if !com.IsFile(patchPath) {
+		log.Trace("PullRequest[%d].testPatch: ignored cruppted data", pr.ID)
+		return nil
+	}
+
+	repoWorkingPool.CheckIn(com.ToStr(pr.BaseRepoID))
+	defer repoWorkingPool.CheckOut(com.ToStr(pr.BaseRepoID))
+
+	log.Trace("PullRequest[%d].testPatch (patchPath): %s", pr.ID, patchPath)
+
+	if err := pr.BaseRepo.UpdateLocalCopyBranch(pr.BaseBranch); err != nil {
+		return fmt.Errorf("UpdateLocalCopy [%d]: %v", pr.BaseRepoID, err)
+	}
+
+	args := []string{"apply", "--check"}
+	if pr.BaseRepo.PullsIgnoreWhitespace {
+		args = append(args, "--ignore-whitespace")
+	}
+	args = append(args, patchPath)
+
+	pr.Status = PULL_REQUEST_STATUS_CHECKING
+	_, stderr, err := process.ExecDir(-1, pr.BaseRepo.LocalCopyPath(),
+		fmt.Sprintf("testPatch (git apply --check): %d", pr.BaseRepo.ID),
+		"git", args...)
+	if err != nil {
+		log.Trace("PullRequest[%d].testPatch (apply): has conflit\n%s", pr.ID, stderr)
+		pr.Status = PULL_REQUEST_STATUS_CONFLICT
+		return nil
+	}
+	return nil
+}
+
+// NewPullRequest creates new pull request with labels for repository.
+func NewPullRequest(repo *Repository, pull *Issue, labelIDs []int64, uuids []string, pr *PullRequest, patch []byte) (err error) {
+	sess := x.NewSession()
+	defer sess.Close()
+	if err = sess.Begin(); err != nil {
+		return err
+	}
+
+	if err = newIssue(sess, NewIssueOptions{
+		Repo:        repo,
+		Issue:       pull,
+		LableIDs:    labelIDs,
+		Attachments: uuids,
+		IsPull:      true,
+	}); err != nil {
+		return fmt.Errorf("newIssue: %v", err)
+	}
+
+	pr.Index = pull.Index
+	if err = repo.SavePatch(pr.Index, patch); err != nil {
+		return fmt.Errorf("SavePatch: %v", err)
+	}
+
+	pr.BaseRepo = repo
+	if err = pr.testPatch(); err != nil {
+		return fmt.Errorf("testPatch: %v", err)
+	}
+	// No conflict appears after test means mergeable.
+	if pr.Status == PULL_REQUEST_STATUS_CHECKING {
+		pr.Status = PULL_REQUEST_STATUS_MERGEABLE
+	}
+
+	pr.IssueID = pull.ID
+	if _, err = sess.Insert(pr); err != nil {
+		return fmt.Errorf("insert pull repo: %v", err)
+	}
+
+	if err = sess.Commit(); err != nil {
+		return fmt.Errorf("Commit: %v", err)
+	}
+
+	if err = NotifyWatchers(&Action{
+		ActUserID:    pull.Poster.ID,
+		ActUserName:  pull.Poster.Name,
+		OpType:       ACTION_CREATE_PULL_REQUEST,
+		Content:      fmt.Sprintf("%d|%s", pull.Index, pull.Title),
+		RepoID:       repo.ID,
+		RepoUserName: repo.Owner.Name,
+		RepoName:     repo.Name,
+		IsPrivate:    repo.IsPrivate,
+	}); err != nil {
+		log.Error(2, "NotifyWatchers: %v", err)
+	}
+	if err = pull.MailParticipants(); err != nil {
+		log.Error(2, "MailParticipants: %v", err)
+	}
+
+	pr.Issue = pull
+	pull.PullRequest = pr
+	if err = PrepareWebhooks(repo, HOOK_EVENT_PULL_REQUEST, &api.PullRequestPayload{
+		Action:      api.HOOK_ISSUE_OPENED,
+		Index:       pull.Index,
+		PullRequest: pr.APIFormat(),
+		Repository:  repo.APIFormat(nil),
+		Sender:      pull.Poster.APIFormat(),
+	}); err != nil {
+		log.Error(2, "PrepareWebhooks: %v", err)
+	}
+
+	return nil
+}
+
+// GetUnmergedPullRequest returnss a pull request that is open and has not been merged
+// by given head/base and repo/branch.
+func GetUnmergedPullRequest(headRepoID, baseRepoID int64, headBranch, baseBranch string) (*PullRequest, error) {
+	pr := new(PullRequest)
+	has, err := x.Where("head_repo_id=? AND head_branch=? AND base_repo_id=? AND base_branch=? AND has_merged=? AND issue.is_closed=?",
+		headRepoID, headBranch, baseRepoID, baseBranch, false, false).
+		Join("INNER", "issue", "issue.id=pull_request.issue_id").Get(pr)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrPullRequestNotExist{0, 0, headRepoID, baseRepoID, headBranch, baseBranch}
+	}
+
+	return pr, nil
+}
+
+// GetUnmergedPullRequestsByHeadInfo returnss all pull requests that are open and has not been merged
+// by given head information (repo and branch).
+func GetUnmergedPullRequestsByHeadInfo(repoID int64, branch string) ([]*PullRequest, error) {
+	prs := make([]*PullRequest, 0, 2)
+	return prs, x.Where("head_repo_id = ? AND head_branch = ? AND has_merged = ? AND issue.is_closed = ?",
+		repoID, branch, false, false).
+		Join("INNER", "issue", "issue.id = pull_request.issue_id").Find(&prs)
+}
+
+// GetUnmergedPullRequestsByBaseInfo returnss all pull requests that are open and has not been merged
+// by given base information (repo and branch).
+func GetUnmergedPullRequestsByBaseInfo(repoID int64, branch string) ([]*PullRequest, error) {
+	prs := make([]*PullRequest, 0, 2)
+	return prs, x.Where("base_repo_id=? AND base_branch=? AND has_merged=? AND issue.is_closed=?",
+		repoID, branch, false, false).
+		Join("INNER", "issue", "issue.id=pull_request.issue_id").Find(&prs)
+}
+
+func getPullRequestByID(e Engine, id int64) (*PullRequest, error) {
+	pr := new(PullRequest)
+	has, err := e.ID(id).Get(pr)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrPullRequestNotExist{id, 0, 0, 0, "", ""}
+	}
+	return pr, pr.loadAttributes(e)
+}
+
+// GetPullRequestByID returns a pull request by given ID.
+func GetPullRequestByID(id int64) (*PullRequest, error) {
+	return getPullRequestByID(x, id)
+}
+
+func getPullRequestByIssueID(e Engine, issueID int64) (*PullRequest, error) {
+	pr := &PullRequest{
+		IssueID: issueID,
+	}
+	has, err := e.Get(pr)
+	if err != nil {
+		return nil, err
+	} else if !has {
+		return nil, ErrPullRequestNotExist{0, issueID, 0, 0, "", ""}
+	}
+	return pr, pr.loadAttributes(e)
+}
+
+// GetPullRequestByIssueID returns pull request by given issue ID.
+func GetPullRequestByIssueID(issueID int64) (*PullRequest, error) {
+	return getPullRequestByIssueID(x, issueID)
+}
+
+// Update updates all fields of pull request.
+func (pr *PullRequest) Update() error {
+	_, err := x.Id(pr.ID).AllCols().Update(pr)
+	return err
+}
+
+// Update updates specific fields of pull request.
+func (pr *PullRequest) UpdateCols(cols ...string) error {
+	_, err := x.Id(pr.ID).Cols(cols...).Update(pr)
+	return err
+}
+
+// UpdatePatch generates and saves a new patch.
+func (pr *PullRequest) UpdatePatch() (err error) {
+	if pr.HeadRepo == nil {
+		log.Trace("PullRequest[%d].UpdatePatch: ignored cruppted data", pr.ID)
+		return nil
+	}
+
+	headGitRepo, err := git.OpenRepository(pr.HeadRepo.RepoPath())
+	if err != nil {
+		return fmt.Errorf("OpenRepository: %v", err)
+	}
+
+	// Add a temporary remote.
+	tmpRemote := com.ToStr(time.Now().UnixNano())
+	if err = headGitRepo.AddRemote(tmpRemote, RepoPath(pr.BaseRepo.MustOwner().Name, pr.BaseRepo.Name), true); err != nil {
+		return fmt.Errorf("AddRemote: %v", err)
+	}
+	defer func() {
+		headGitRepo.RemoveRemote(tmpRemote)
+	}()
+	remoteBranch := "remotes/" + tmpRemote + "/" + pr.BaseBranch
+	pr.MergeBase, err = headGitRepo.GetMergeBase(remoteBranch, pr.HeadBranch)
+	if err != nil {
+		return fmt.Errorf("GetMergeBase: %v", err)
+	} else if err = pr.Update(); err != nil {
+		return fmt.Errorf("Update: %v", err)
+	}
+
+	patch, err := headGitRepo.GetPatch(pr.MergeBase, pr.HeadBranch)
+	if err != nil {
+		return fmt.Errorf("GetPatch: %v", err)
+	}
+
+	if err = pr.BaseRepo.SavePatch(pr.Index, patch); err != nil {
+		return fmt.Errorf("BaseRepo.SavePatch: %v", err)
+	}
+
+	return nil
+}
+
+// PushToBaseRepo pushes commits from branches of head repository to
+// corresponding branches of base repository.
+// FIXME: Only push branches that are actually updates?
+func (pr *PullRequest) PushToBaseRepo() (err error) {
+	log.Trace("PushToBaseRepo[%d]: pushing commits to base repo 'refs/pull/%d/head'", pr.BaseRepoID, pr.Index)
+
+	headRepoPath := pr.HeadRepo.RepoPath()
+	headGitRepo, err := git.OpenRepository(headRepoPath)
+	if err != nil {
+		return fmt.Errorf("OpenRepository: %v", err)
+	}
+
+	tmpRemoteName := fmt.Sprintf("tmp-pull-%d", pr.ID)
+	if err = headGitRepo.AddRemote(tmpRemoteName, pr.BaseRepo.RepoPath(), false); err != nil {
+		return fmt.Errorf("headGitRepo.AddRemote: %v", err)
+	}
+	// Make sure to remove the remote even if the push fails
+	defer headGitRepo.RemoveRemote(tmpRemoteName)
+
+	headFile := fmt.Sprintf("refs/pull/%d/head", pr.Index)
+
+	// Remove head in case there is a conflict.
+	os.Remove(path.Join(pr.BaseRepo.RepoPath(), headFile))
+
+	if err = git.Push(headRepoPath, tmpRemoteName, fmt.Sprintf("%s:%s", pr.HeadBranch, headFile)); err != nil {
+		return fmt.Errorf("Push: %v", err)
+	}
+
+	return nil
+}
+
+// AddToTaskQueue adds itself to pull request test task queue.
+func (pr *PullRequest) AddToTaskQueue() {
+	go PullRequestQueue.AddFunc(pr.ID, func() {
+		pr.Status = PULL_REQUEST_STATUS_CHECKING
+		if err := pr.UpdateCols("status"); err != nil {
+			log.Error(3, "AddToTaskQueue.UpdateCols[%d].(add to queue): %v", pr.ID, err)
+		}
+	})
+}
+
+type PullRequestList []*PullRequest
+
+func (prs PullRequestList) loadAttributes(e Engine) (err error) {
+	if len(prs) == 0 {
+		return nil
+	}
+
+	// Load issues
+	set := make(map[int64]*Issue)
+	for i := range prs {
+		set[prs[i].IssueID] = nil
+	}
+	issueIDs := make([]int64, 0, len(prs))
+	for issueID := range set {
+		issueIDs = append(issueIDs, issueID)
+	}
+	issues := make([]*Issue, 0, len(issueIDs))
+	if err = e.Where("id > 0").In("id", issueIDs).Find(&issues); err != nil {
+		return fmt.Errorf("find issues: %v", err)
+	}
+	for i := range issues {
+		set[issues[i].ID] = issues[i]
+	}
+	for i := range prs {
+		prs[i].Issue = set[prs[i].IssueID]
+	}
+
+	// Load attributes
+	for i := range prs {
+		if err = prs[i].loadAttributes(e); err != nil {
+			return fmt.Errorf("loadAttributes [%d]: %v", prs[i].ID, err)
+		}
+	}
+
+	return nil
+}
+
+func (prs PullRequestList) LoadAttributes() error {
+	return prs.loadAttributes(x)
+}
+
+func addHeadRepoTasks(prs []*PullRequest) {
+	for _, pr := range prs {
+		log.Trace("addHeadRepoTasks[%d]: composing new test task", pr.ID)
+		if err := pr.UpdatePatch(); err != nil {
+			log.Error(4, "UpdatePatch: %v", err)
+			continue
+		} else if err := pr.PushToBaseRepo(); err != nil {
+			log.Error(4, "PushToBaseRepo: %v", err)
+			continue
+		}
+
+		pr.AddToTaskQueue()
+	}
+}
+
+// AddTestPullRequestTask adds new test tasks by given head/base repository and head/base branch,
+// and generate new patch for testing as needed.
+func AddTestPullRequestTask(doer *User, repoID int64, branch string, isSync bool) {
+	log.Trace("AddTestPullRequestTask [head_repo_id: %d, head_branch: %s]: finding pull requests", repoID, branch)
+	prs, err := GetUnmergedPullRequestsByHeadInfo(repoID, branch)
+	if err != nil {
+		log.Error(2, "Find pull requests [head_repo_id: %d, head_branch: %s]: %v", repoID, branch, err)
+		return
+	}
+
+	if isSync {
+		if err = PullRequestList(prs).LoadAttributes(); err != nil {
+			log.Error(2, "PullRequestList.LoadAttributes: %v", err)
+		}
+
+		if err == nil {
+			for _, pr := range prs {
+				pr.Issue.PullRequest = pr
+				if err = pr.Issue.LoadAttributes(); err != nil {
+					log.Error(2, "LoadAttributes: %v", err)
+					continue
+				}
+				if err = PrepareWebhooks(pr.Issue.Repo, HOOK_EVENT_PULL_REQUEST, &api.PullRequestPayload{
+					Action:      api.HOOK_ISSUE_SYNCHRONIZED,
+					Index:       pr.Issue.Index,
+					PullRequest: pr.Issue.PullRequest.APIFormat(),
+					Repository:  pr.Issue.Repo.APIFormat(nil),
+					Sender:      doer.APIFormat(),
+				}); err != nil {
+					log.Error(2, "PrepareWebhooks [pull_id: %v]: %v", pr.ID, err)
+					continue
+				}
+			}
+		}
+	}
+
+	addHeadRepoTasks(prs)
+
+	log.Trace("AddTestPullRequestTask [base_repo_id: %d, base_branch: %s]: finding pull requests", repoID, branch)
+	prs, err = GetUnmergedPullRequestsByBaseInfo(repoID, branch)
+	if err != nil {
+		log.Error(2, "Find pull requests [base_repo_id: %d, base_branch: %s]: %v", repoID, branch, err)
+		return
+	}
+	for _, pr := range prs {
+		pr.AddToTaskQueue()
+	}
+}
+
+func ChangeUsernameInPullRequests(oldUserName, newUserName string) error {
+	pr := PullRequest{
+		HeadUserName: strings.ToLower(newUserName),
+	}
+	_, err := x.Cols("head_user_name").Where("head_user_name = ?", strings.ToLower(oldUserName)).Update(pr)
+	return err
+}
+
+// checkAndUpdateStatus checks if pull request is possible to levaing checking status,
+// and set to be either conflict or mergeable.
+func (pr *PullRequest) checkAndUpdateStatus() {
+	// Status is not changed to conflict means mergeable.
+	if pr.Status == PULL_REQUEST_STATUS_CHECKING {
+		pr.Status = PULL_REQUEST_STATUS_MERGEABLE
+	}
+
+	// Make sure there is no waiting test to process before levaing the checking status.
+	if !PullRequestQueue.Exist(pr.ID) {
+		if err := pr.UpdateCols("status"); err != nil {
+			log.Error(4, "Update[%d]: %v", pr.ID, err)
+		}
+	}
+}
+
+// TestPullRequests checks and tests untested patches of pull requests.
+// TODO: test more pull requests at same time.
+func TestPullRequests() {
+	prs := make([]*PullRequest, 0, 10)
+	x.Iterate(PullRequest{
+		Status: PULL_REQUEST_STATUS_CHECKING,
+	},
+		func(idx int, bean interface{}) error {
+			pr := bean.(*PullRequest)
+
+			if err := pr.LoadAttributes(); err != nil {
+				log.Error(3, "LoadAttributes: %v", err)
+				return nil
+			}
+
+			if err := pr.testPatch(); err != nil {
+				log.Error(3, "testPatch: %v", err)
+				return nil
+			}
+			prs = append(prs, pr)
+			return nil
+		})
+
+	// Update pull request status.
+	for _, pr := range prs {
+		pr.checkAndUpdateStatus()
+	}
+
+	// Start listening on new test requests.
+	for prID := range PullRequestQueue.Queue() {
+		log.Trace("TestPullRequests[%v]: processing test task", prID)
+		PullRequestQueue.Remove(prID)
+
+		pr, err := GetPullRequestByID(com.StrTo(prID).MustInt64())
+		if err != nil {
+			log.Error(4, "GetPullRequestByID[%s]: %v", prID, err)
+			continue
+		} else if err = pr.testPatch(); err != nil {
+			log.Error(4, "testPatch[%d]: %v", pr.ID, err)
+			continue
+		}
+
+		pr.checkAndUpdateStatus()
+	}
+}
+
+func InitTestPullRequests() {
+	go TestPullRequests()
+}