Fix bug on pull requests when transfer head repository (#8564)

* fix bug on pull requests when transfer head repository

* add migration and fix lint

* fix tests and add a cache check on LoadBaseRepo

6 files changed, 49 insertions, 35 deletions

diff --git a/models/fixtures/pull_request.yml b/models/fixtures/pull_request.yml
index baaaf6bb8a..505584ea18 100644
--- a/models/fixtures/pull_request.yml
+++ b/models/fixtures/pull_request.yml
@@ -6,7 +6,6 @@
   index: 2
   head_repo_id: 1
   base_repo_id: 1
-  head_user_name: user1
   head_branch: branch1
   base_branch: master
   merge_base: 1234567890abcdef
@@ -21,7 +20,6 @@
   index: 3
   head_repo_id: 1
   base_repo_id: 1
-  head_user_name: user1
   head_branch: branch2
   base_branch: master
   merge_base: fedcba9876543210
@@ -35,7 +33,6 @@
   index: 1
   head_repo_id: 11
   base_repo_id: 10
-  head_user_name: user13
   head_branch: branch2
   base_branch: master
   merge_base: 0abcb056019adb83
diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 19b1095cd3..8064eccfc1 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -258,6 +258,8 @@ var migrations = []Migration{
 	NewMigration("update migration repositories' service type", updateMigrationServiceTypes),
 	// v101 -> v102
 	NewMigration("change length of some external login users columns", changeSomeColumnsLengthOfExternalLoginUser),
+	// v102 -> v103
+	NewMigration("update migration repositories' service type", dropColumnHeadUserNameOnPullRequest),
 }
 
 // Migrate database to current version
diff --git a/models/migrations/v102.go b/models/migrations/v102.go
new file mode 100644
index 0000000000..74e8574ec3
--- /dev/null
+++ b/models/migrations/v102.go
@@ -0,0 +1,15 @@
+// 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 migrations
+
+import (
+	"xorm.io/xorm"
+)
+
+func dropColumnHeadUserNameOnPullRequest(x *xorm.Engine) error {
+	sess := x.NewSession()
+	defer sess.Close()
+	return dropTableColumns(sess, "pull_request", "head_user_name")
+}
diff --git a/models/pull.go b/models/pull.go
index 817ea09cca..a3554a1b3d 100644
--- a/models/pull.go
+++ b/models/pull.go
@@ -66,7 +66,6 @@ type PullRequest struct {
 	HeadRepo        *Repository `xorm:"-"`
 	BaseRepoID      int64       `xorm:"INDEX"`
 	BaseRepo        *Repository `xorm:"-"`
-	HeadUserName    string
 	HeadBranch      string
 	BaseBranch      string
 	ProtectedBranch *ProtectedBranch `xorm:"-"`
@@ -79,6 +78,15 @@ type PullRequest struct {
 	MergedUnix     timeutil.TimeStamp `xorm:"updated INDEX"`
 }
 
+// MustHeadUserName returns the HeadRepo's username if failed return blank
+func (pr *PullRequest) MustHeadUserName() string {
+	if err := pr.LoadHeadRepo(); err != nil {
+		log.Error("LoadHeadRepo: %v", err)
+		return ""
+	}
+	return pr.HeadRepo.MustOwnerName()
+}
+
 // Note: don't try to get Issue because will end up recursive querying.
 func (pr *PullRequest) loadAttributes(e Engine) (err error) {
 	if pr.HasMerged && pr.Merger == nil {
@@ -102,6 +110,10 @@ func (pr *PullRequest) LoadAttributes() error {
 // LoadBaseRepo loads pull request base repository from database
 func (pr *PullRequest) LoadBaseRepo() error {
 	if pr.BaseRepo == nil {
+		if pr.HeadRepoID == pr.BaseRepoID && pr.HeadRepo != nil {
+			pr.BaseRepo = pr.HeadRepo
+			return nil
+		}
 		var repo Repository
 		if has, err := x.ID(pr.BaseRepoID).Get(&repo); err != nil {
 			return err
@@ -113,6 +125,24 @@ func (pr *PullRequest) LoadBaseRepo() error {
 	return nil
 }
 
+// LoadHeadRepo loads pull request head repository from database
+func (pr *PullRequest) LoadHeadRepo() error {
+	if pr.HeadRepo == nil {
+		if pr.HeadRepoID == pr.BaseRepoID && pr.BaseRepo != nil {
+			pr.HeadRepo = pr.BaseRepo
+			return nil
+		}
+		var repo Repository
+		if has, err := x.ID(pr.HeadRepoID).Get(&repo); err != nil {
+			return err
+		} else if !has {
+			return ErrRepoNotExist{ID: pr.BaseRepoID}
+		}
+		pr.HeadRepo = &repo
+	}
+	return nil
+}
+
 // LoadIssue loads issue information from database
 func (pr *PullRequest) LoadIssue() (err error) {
 	return pr.loadIssue(x)
@@ -152,7 +182,7 @@ func (pr *PullRequest) GetDefaultMergeMessage() string {
 			return ""
 		}
 	}
-	return fmt.Sprintf("Merge branch '%s' of %s/%s into %s", pr.HeadBranch, pr.HeadUserName, pr.HeadRepo.Name, pr.BaseBranch)
+	return fmt.Sprintf("Merge branch '%s' of %s/%s into %s", pr.HeadBranch, pr.MustHeadUserName(), pr.HeadRepo.Name, pr.BaseBranch)
 }
 
 // GetDefaultSquashMessage returns default message used when squash and merging pull request
@@ -1072,18 +1102,6 @@ func (prs PullRequestList) InvalidateCodeComments(doer *User, repo *git.Reposito
 	return prs.invalidateCodeComments(x, doer, repo, branch)
 }
 
-// ChangeUsernameInPullRequests changes the name of head_user_name
-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 leaving checking status,
 // and set to be either conflict or mergeable.
 func (pr *PullRequest) checkAndUpdateStatus() {
diff --git a/models/pull_test.go b/models/pull_test.go
index df051d51bc..8e2436b1a2 100644
--- a/models/pull_test.go
+++ b/models/pull_test.go
@@ -232,20 +232,6 @@ func TestPullRequestList_LoadAttributes(t *testing.T) {
 
 // TODO TestAddTestPullRequestTask
 
-func TestChangeUsernameInPullRequests(t *testing.T) {
-	assert.NoError(t, PrepareTestDatabase())
-	const newUsername = "newusername"
-	assert.NoError(t, ChangeUsernameInPullRequests("user1", newUsername))
-
-	prs := make([]*PullRequest, 0, 10)
-	assert.NoError(t, x.Where("head_user_name = ?", newUsername).Find(&prs))
-	assert.Len(t, prs, 2)
-	for _, pr := range prs {
-		assert.Equal(t, newUsername, pr.HeadUserName)
-	}
-	CheckConsistencyFor(t, &PullRequest{})
-}
-
 func TestPullRequest_IsWorkInProgress(t *testing.T) {
 	assert.NoError(t, PrepareTestDatabase())
 
diff --git a/models/user.go b/models/user.go
index c393d8dce5..a3679c9a5b 100644
--- a/models/user.go
+++ b/models/user.go
@@ -994,10 +994,6 @@ func ChangeUserName(u *User, newUserName string) (err error) {
 		return ErrUserAlreadyExist{newUserName}
 	}
 
-	if err = ChangeUsernameInPullRequests(u.Name, newUserName); err != nil {
-		return fmt.Errorf("ChangeUsernameInPullRequests: %v", err)
-	}
-
 	// Do not fail if directory does not exist
 	if err = os.Rename(UserPath(u.Name), UserPath(newUserName)); err != nil && !os.IsNotExist(err) {
 		return fmt.Errorf("Rename user directory: %v", err)