From 8e26807e076fa4f9de745688ecf572ce6c8f0cd0 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Wed, 1 Apr 2020 13:22:14 +0200
Subject: [PATCH 1/5] add docu how to use func **createTemporaryRepo**

---
 services/pull/temp_repo.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/services/pull/temp_repo.go b/services/pull/temp_repo.go
index ffac92ade5e07..91f48d0626816 100644
--- a/services/pull/temp_repo.go
+++ b/services/pull/temp_repo.go
@@ -16,6 +16,8 @@ import (
 	"code.gitea.io/gitea/modules/log"
 )
 
+// createTemporaryRepo creates a temporary repo with "base" for pr.BaseBranch and "tracking" for  pr.HeadBranch
+// it also create a second base branch called "original_base"
 func createTemporaryRepo(pr *models.PullRequest) (string, error) {
 	if err := pr.LoadHeadRepo(); err != nil {
 		log.Error("LoadHeadRepo: %v", err)

From abd363941bc6eea816266ed3a2bb9153905a4835 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Wed, 1 Apr 2020 13:27:03 +0200
Subject: [PATCH 2/5] fix by using createTemporaryRepo

---
 services/pull/update.go | 53 ++++-------------------------------------
 1 file changed, 4 insertions(+), 49 deletions(-)

diff --git a/services/pull/update.go b/services/pull/update.go
index 66921abefa2f2..6898010673c10 100644
--- a/services/pull/update.go
+++ b/services/pull/update.go
@@ -6,8 +6,6 @@ package pull
 
 import (
 	"fmt"
-	"strconv"
-	"strings"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/git"
@@ -74,54 +72,11 @@ func GetDiverging(pr *models.PullRequest) (*git.DivergeObject, error) {
 		return nil, err
 	}
 
-	headRepoPath := pr.HeadRepo.RepoPath()
-	headGitRepo, err := git.OpenRepository(headRepoPath)
+	tmpRepo, err := createTemporaryRepo(pr)
 	if err != nil {
-		return nil, fmt.Errorf("OpenRepository: %v", err)
-	}
-	defer headGitRepo.Close()
-
-	if pr.IsSameRepo() {
-		diff, err := git.GetDivergingCommits(pr.HeadRepo.RepoPath(), pr.BaseBranch, pr.HeadBranch)
-		return &diff, err
-	}
-
-	tmpRemoteName := fmt.Sprintf("tmp-pull-%d-base", pr.ID)
-	if err = headGitRepo.AddRemote(tmpRemoteName, pr.BaseRepo.RepoPath(), true); err != nil {
-		return nil, fmt.Errorf("headGitRepo.AddRemote: %v", err)
-	}
-	// Make sure to remove the remote even if the push fails
-	defer func() {
-		if err := headGitRepo.RemoveRemote(tmpRemoteName); err != nil {
-			log.Error("CountDiverging: RemoveRemote: %s", err)
-		}
-	}()
-
-	// $(git rev-list --count tmp-pull-1-base/master..feature) commits ahead of master
-	ahead, errorAhead := checkDivergence(headRepoPath, fmt.Sprintf("%s/%s", tmpRemoteName, pr.BaseBranch), pr.HeadBranch)
-	if errorAhead != nil {
-		return &git.DivergeObject{}, errorAhead
-	}
-
-	// $(git rev-list --count feature..tmp-pull-1-base/master) commits behind master
-	behind, errorBehind := checkDivergence(headRepoPath, pr.HeadBranch, fmt.Sprintf("%s/%s", tmpRemoteName, pr.BaseBranch))
-	if errorBehind != nil {
-		return &git.DivergeObject{}, errorBehind
+		return nil, err
 	}
 
-	return &git.DivergeObject{Ahead: ahead, Behind: behind}, nil
-}
-
-func checkDivergence(repoPath string, baseBranch string, targetBranch string) (int, error) {
-	branches := fmt.Sprintf("%s..%s", baseBranch, targetBranch)
-	cmd := git.NewCommand("rev-list", "--count", branches)
-	stdout, err := cmd.RunInDir(repoPath)
-	if err != nil {
-		return -1, err
-	}
-	outInteger, errInteger := strconv.Atoi(strings.Trim(stdout, "\n"))
-	if errInteger != nil {
-		return -1, errInteger
-	}
-	return outInteger, nil
+	diff, err := git.GetDivergingCommits(tmpRepo, "base", "tracking")
+	return &diff, err
 }

From 4ee6846e829c568c4922409e7c778525eaf1afd7 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Wed, 1 Apr 2020 13:27:17 +0200
Subject: [PATCH 3/5] correct Trace Log

---
 services/pull/update.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/services/pull/update.go b/services/pull/update.go
index 6898010673c10..52871863393d2 100644
--- a/services/pull/update.go
+++ b/services/pull/update.go
@@ -64,7 +64,7 @@ func IsUserAllowedToUpdate(pull *models.PullRequest, user *models.User) (bool, e
 
 // GetDiverging determines how many commits a PR is ahead or behind the PR base branch
 func GetDiverging(pr *models.PullRequest) (*git.DivergeObject, error) {
-	log.Trace("PushToBaseRepo[%d]: pushing commits to base repo '%s'", pr.BaseRepoID, pr.GetGitRefName())
+	log.Trace("GetDiverging[%d]: compare commits", pr.ID)
 	if err := pr.LoadBaseRepo(); err != nil {
 		return nil, err
 	}

From abd1e93f36e29e6853cffb2f62796811288d4b21 Mon Sep 17 00:00:00 2001
From: zeripath <art27@cantab.net>
Date: Wed, 1 Apr 2020 17:24:25 +0100
Subject: [PATCH 4/5] Remove the temporary repo at the end of the function

---
 services/pull/update.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/services/pull/update.go b/services/pull/update.go
index 52871863393d2..e778f609c5c4d 100644
--- a/services/pull/update.go
+++ b/services/pull/update.go
@@ -76,6 +76,11 @@ func GetDiverging(pr *models.PullRequest) (*git.DivergeObject, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer func() {
+		if err := models.RemoveTemporaryPath(tmpRepo); err != nil {
+			log.Error("Merge: RemoveTemporaryPath: %s", err)
+		}
+	}()
 
 	diff, err := git.GetDivergingCommits(tmpRepo, "base", "tracking")
 	return &diff, err

From cc65627fb4310efcbb9c258918b995f165e29d6b Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Wed, 1 Apr 2020 18:25:00 +0200
Subject: [PATCH 5/5] delete tmp afterwards

---
 services/pull/update.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/services/pull/update.go b/services/pull/update.go
index e778f609c5c4d..2ccbcf00a322e 100644
--- a/services/pull/update.go
+++ b/services/pull/update.go
@@ -74,6 +74,7 @@ func GetDiverging(pr *models.PullRequest) (*git.DivergeObject, error) {
 
 	tmpRepo, err := createTemporaryRepo(pr)
 	if err != nil {
+		log.Error("CreateTemporaryPath: %v", err)
 		return nil, err
 	}
 	defer func() {