models/issue: improve quality and performance of NewIssue function

models/repo.go

@@ -316,33 +316,43 @@ func (repo *Repository) DeleteWiki() {
 	}
 }
 
-// GetAssignees returns all users that have write access of repository.
-func (repo *Repository) GetAssignees() (_ []*User, err error) {
-	if err = repo.GetOwner(); err != nil {
+func (repo *Repository) getAssignees(e Engine) (_ []*User, err error) {
+	if err = repo.getOwner(e); err != nil {
 		return nil, err
 	}
 
 	accesses := make([]*Access, 0, 10)
-	if err = x.Where("repo_id=? AND mode>=?", repo.ID, ACCESS_MODE_WRITE).Find(&accesses); err != nil {
+	if err = e.Where("repo_id = ? AND mode >= ?", repo.ID, ACCESS_MODE_WRITE).Find(&accesses); err != nil {
 		return nil, err
 	}
+	if len(accesses) == 0 {
+		return []*User{}, nil
+	}
 
-	users := make([]*User, 0, len(accesses)+1) // Just waste 1 unit does not matter.
+	userIDs := make([]int64, len(accesses))
+	for i := 0; i < len(accesses); i++ {
+		userIDs[i] = accesses[i].UserID
+	}
+
+	// Leave a seat for owner itself to append later, but if owner is an organization
+	// and just waste 1 unit is cheaper than re-allocate memory once.
+	users := make([]*User, 0, len(userIDs)+1)
+	if err = e.In("id", userIDs).Find(&users); err != nil {
+		return nil, err
+	}
 	if !repo.Owner.IsOrganization() {
 		users = append(users, repo.Owner)
 	}
 
-	var u *User
-	for i := range accesses {
-		u, err = GetUserByID(accesses[i].UserID)
-		if err != nil {
-			return nil, err
-		}
-		users = append(users, u)
-	}
 	return users, nil
 }
 
+// GetAssignees returns all users that have write access and can be assigned to issues
+// of the repository,
+func (repo *Repository) GetAssignees() (_ []*User, err error) {
+	return repo.getAssignees(x)
+}
+
 // GetAssigneeByID returns the user that has write access of repository by given ID.
 func (repo *Repository) GetAssigneeByID(userID int64) (*User, error) {
 	return GetAssigneeByID(repo, userID)
@@ -420,6 +430,8 @@ func (repo *Repository) AllowsPulls() bool {
 	return repo.CanEnablePulls() && repo.EnablePulls
 }
 
+// FIXME: should have a mutex to prevent producing same index for two issues that are created
+// closely enough.
 func (repo *Repository) NextIssueIndex() int64 {
 	return int64(repo.NumIssues+repo.NumPulls) + 1
 }