Improve trace logging for pulls and processes (#22633)

Our trace logging is far from perfect and is difficult to follow.

This PR:

* Add trace logging for process manager add and remove.
* Fixes an errant read file for git refs in getMergeCommit
* Brings in the pullrequest `String` and `ColorFormat` methods
introduced in #22568
* Adds a lot more logging in to testPR etc.

Ref #22578

---------

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

9 files changed, 230 insertions, 146 deletions

diff --git a/models/issues/pull.go b/models/issues/pull.go
index 6ff6502e4e..044fb5fa04 100644
--- a/models/issues/pull.go
+++ b/models/issues/pull.go
@@ -8,6 +8,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"strconv"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
@@ -132,6 +133,27 @@ const (
 	PullRequestStatusAncestor
 )
 
+func (status PullRequestStatus) String() string {
+	switch status {
+	case PullRequestStatusConflict:
+		return "CONFLICT"
+	case PullRequestStatusChecking:
+		return "CHECKING"
+	case PullRequestStatusMergeable:
+		return "MERGEABLE"
+	case PullRequestStatusManuallyMerged:
+		return "MANUALLY_MERGED"
+	case PullRequestStatusError:
+		return "ERROR"
+	case PullRequestStatusEmpty:
+		return "EMPTY"
+	case PullRequestStatusAncestor:
+		return "ANCESTOR"
+	default:
+		return strconv.Itoa(int(status))
+	}
+}
+
 // PullRequestFlow the flow of pull request
 type PullRequestFlow int
 
@@ -202,6 +224,42 @@ func DeletePullsByBaseRepoID(ctx context.Context, repoID int64) error {
 	return err
 }
 
+// ColorFormat writes a colored string to identify this struct
+func (pr *PullRequest) ColorFormat(s fmt.State) {
+	if pr == nil {
+		log.ColorFprintf(s, "PR[%d]%s#%d[%s...%s:%s]",
+			log.NewColoredIDValue(0),
+			log.NewColoredValue("<nil>/<nil>"),
+			log.NewColoredIDValue(0),
+			log.NewColoredValue("<nil>"),
+			log.NewColoredValue("<nil>/<nil>"),
+			log.NewColoredValue("<nil>"),
+		)
+		return
+	}
+
+	log.ColorFprintf(s, "PR[%d]", log.NewColoredIDValue(pr.ID))
+	if pr.BaseRepo != nil {
+		log.ColorFprintf(s, "%s#%d[%s...", log.NewColoredValue(pr.BaseRepo.FullName()),
+			log.NewColoredIDValue(pr.Index), log.NewColoredValue(pr.BaseBranch))
+	} else {
+		log.ColorFprintf(s, "Repo[%d]#%d[%s...", log.NewColoredIDValue(pr.BaseRepoID),
+			log.NewColoredIDValue(pr.Index), log.NewColoredValue(pr.BaseBranch))
+	}
+	if pr.HeadRepoID == pr.BaseRepoID {
+		log.ColorFprintf(s, "%s]", log.NewColoredValue(pr.HeadBranch))
+	} else if pr.HeadRepo != nil {
+		log.ColorFprintf(s, "%s:%s]", log.NewColoredValue(pr.HeadRepo.FullName()), log.NewColoredValue(pr.HeadBranch))
+	} else {
+		log.ColorFprintf(s, "Repo[%d]:%s]", log.NewColoredIDValue(pr.HeadRepoID), log.NewColoredValue(pr.HeadBranch))
+	}
+}
+
+// String represents the pr as a simple string
+func (pr *PullRequest) String() string {
+	return log.ColorFormatAsString(pr)
+}
+
 // MustHeadUserName returns the HeadRepo's username if failed return blank
 func (pr *PullRequest) MustHeadUserName(ctx context.Context) string {
 	if err := pr.LoadHeadRepo(ctx); err != nil {
@@ -234,7 +292,8 @@ func (pr *PullRequest) LoadAttributes(ctx context.Context) (err error) {
 	return nil
 }
 
-// LoadHeadRepo loads the head repository
+// LoadHeadRepo loads the head repository, pr.HeadRepo will remain nil if it does not exist
+// and thus ErrRepoNotExist will never be returned
 func (pr *PullRequest) LoadHeadRepo(ctx context.Context) (err error) {
 	if !pr.isHeadRepoLoaded && pr.HeadRepo == nil && pr.HeadRepoID > 0 {
 		if pr.HeadRepoID == pr.BaseRepoID {
@@ -249,14 +308,14 @@ func (pr *PullRequest) LoadHeadRepo(ctx context.Context) (err error) {
 
 		pr.HeadRepo, err = repo_model.GetRepositoryByID(ctx, pr.HeadRepoID)
 		if err != nil && !repo_model.IsErrRepoNotExist(err) { // Head repo maybe deleted, but it should still work
-			return fmt.Errorf("GetRepositoryByID(head): %w", err)
+			return fmt.Errorf("pr[%d].LoadHeadRepo[%d]: %w", pr.ID, pr.HeadRepoID, err)
 		}
 		pr.isHeadRepoLoaded = true
 	}
 	return nil
 }
 
-// LoadBaseRepo loads the target repository
+// LoadBaseRepo loads the target repository. ErrRepoNotExist may be returned.
 func (pr *PullRequest) LoadBaseRepo(ctx context.Context) (err error) {
 	if pr.BaseRepo != nil {
 		return nil
@@ -274,7 +333,7 @@ func (pr *PullRequest) LoadBaseRepo(ctx context.Context) (err error) {
 
 	pr.BaseRepo, err = repo_model.GetRepositoryByID(ctx, pr.BaseRepoID)
 	if err != nil {
-		return fmt.Errorf("repo_model.GetRepositoryByID(base): %w", err)
+		return fmt.Errorf("pr[%d].LoadBaseRepo[%d]: %w", pr.ID, pr.BaseRepoID, err)
 	}
 	return nil
 }
diff --git a/modules/log/colors.go b/modules/log/colors.go
index 02781afe84..85e205cb67 100644
--- a/modules/log/colors.go
+++ b/modules/log/colors.go
@@ -383,6 +383,13 @@ func (cv *ColoredValue) Format(s fmt.State, c rune) {
 	s.Write(*cv.resetBytes)
 }
 
+// ColorFormatAsString returns the result of the ColorFormat without the color
+func ColorFormatAsString(colorVal ColorFormatted) string {
+	s := new(strings.Builder)
+	_, _ = ColorFprintf(&protectedANSIWriter{w: s, mode: removeColor}, "%-v", colorVal)
+	return s.String()
+}
+
 // SetColorBytes will allow a user to set the colorBytes of a colored value
 func (cv *ColoredValue) SetColorBytes(colorBytes []byte) {
 	cv.colorBytes = &colorBytes
diff --git a/modules/log/log.go b/modules/log/log.go
index 73f908dfab..9057cda37e 100644
--- a/modules/log/log.go
+++ b/modules/log/log.go
@@ -9,6 +9,8 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+
+	"code.gitea.io/gitea/modules/process"
 )
 
 type loggerMap struct {
@@ -285,6 +287,15 @@ func (l *LoggerAsWriter) Log(msg string) {
 }
 
 func init() {
+	process.Trace = func(start bool, pid process.IDType, description string, parentPID process.IDType, typ string) {
+		if start && parentPID != "" {
+			Log(1, TRACE, "Start %s: %s (from %s) (%s)", NewColoredValue(pid, FgHiYellow), description, NewColoredValue(parentPID, FgYellow), NewColoredValue(typ, Reset))
+		} else if start {
+			Log(1, TRACE, "Start %s: %s (%s)", NewColoredValue(pid, FgHiYellow), description, NewColoredValue(typ, Reset))
+		} else {
+			Log(1, TRACE, "Done %s: %s", NewColoredValue(pid, FgHiYellow), NewColoredValue(description, Reset))
+		}
+	}
 	_, filename, _, _ := runtime.Caller(0)
 	prefix = strings.TrimSuffix(filename, "modules/log/log.go")
 	if prefix == filename {
diff --git a/modules/process/manager.go b/modules/process/manager.go
index 1272510067..fdfca3db7a 100644
--- a/modules/process/manager.go
+++ b/modules/process/manager.go
@@ -6,6 +6,7 @@ package process
 
 import (
 	"context"
+	"log"
 	"runtime/pprof"
 	"strconv"
 	"sync"
@@ -43,6 +44,18 @@ type IDType string
 // - it is simply an alias for context.CancelFunc and is only for documentary purposes
 type FinishedFunc = context.CancelFunc
 
+var Trace = defaultTrace // this global can be overridden by particular logging packages - thus avoiding import cycles
+
+func defaultTrace(start bool, pid IDType, description string, parentPID IDType, typ string) {
+	if start && parentPID != "" {
+		log.Printf("start process %s: %s (from %s) (%s)", pid, description, parentPID, typ)
+	} else if start {
+		log.Printf("start process %s: %s (%s)", pid, description, typ)
+	} else {
+		log.Printf("end process %s: %s", pid, description)
+	}
+}
+
 // Manager manages all processes and counts PIDs.
 type Manager struct {
 	mutex sync.Mutex
@@ -154,6 +167,7 @@ func (pm *Manager) Add(ctx context.Context, description string, cancel context.C
 
 	pm.processMap[pid] = process
 	pm.mutex.Unlock()
+	Trace(true, pid, description, parentPID, processType)
 
 	pprofCtx := pprof.WithLabels(ctx, pprof.Labels(DescriptionPProfLabel, description, PPIDPProfLabel, string(parentPID), PIDPProfLabel, string(pid), ProcessTypePProfLabel, processType))
 	if currentlyRunning {
@@ -185,18 +199,12 @@ func (pm *Manager) nextPID() (start time.Time, pid IDType) {
 	return start, pid
 }
 
-// Remove a process from the ProcessManager.
-func (pm *Manager) Remove(pid IDType) {
-	pm.mutex.Lock()
-	delete(pm.processMap, pid)
-	pm.mutex.Unlock()
-}
-
 func (pm *Manager) remove(process *process) {
 	pm.mutex.Lock()
 	defer pm.mutex.Unlock()
 	if p := pm.processMap[process.PID]; p == process {
 		delete(pm.processMap, process.PID)
+		Trace(false, process.PID, process.Description, process.ParentPID, process.Type)
 	}
 }
 
diff --git a/modules/process/manager_test.go b/modules/process/manager_test.go
index 527072713f..2e2e35d24a 100644
--- a/modules/process/manager_test.go
+++ b/modules/process/manager_test.go
@@ -82,7 +82,7 @@ func TestManager_Remove(t *testing.T) {
 
 	assert.NotEqual(t, GetContext(p1Ctx).GetPID(), GetContext(p2Ctx).GetPID(), "expected to get different pids got %s == %s", GetContext(p2Ctx).GetPID(), GetContext(p1Ctx).GetPID())
 
-	pm.Remove(GetPID(p2Ctx))
+	finished()
 
 	_, exists := pm.processMap[GetPID(p2Ctx)]
 	assert.False(t, exists, "PID %d is in the list but shouldn't", GetPID(p2Ctx))
diff --git a/routers/web/repo/pull.go b/routers/web/repo/pull.go
index 71bc98d13d..11d336d4ec 100644
--- a/routers/web/repo/pull.go
+++ b/routers/web/repo/pull.go
@@ -926,59 +926,54 @@ func MergePullRequest(ctx *context.Context) {
 	pr := issue.PullRequest
 	pr.Issue = issue
 	pr.Issue.Repo = ctx.Repo.Repository
-	manuallMerge := repo_model.MergeStyle(form.Do) == repo_model.MergeStyleManuallyMerged
+	manualMerge := repo_model.MergeStyle(form.Do) == repo_model.MergeStyleManuallyMerged
 	forceMerge := form.ForceMerge != nil && *form.ForceMerge
 
 	// start with merging by checking
-	if err := pull_service.CheckPullMergable(ctx, ctx.Doer, &ctx.Repo.Permission, pr, manuallMerge, forceMerge); err != nil {
-		if errors.Is(err, pull_service.ErrIsClosed) {
+	if err := pull_service.CheckPullMergable(ctx, ctx.Doer, &ctx.Repo.Permission, pr, manualMerge, forceMerge); err != nil {
+		switch {
+		case errors.Is(err, pull_service.ErrIsClosed):
 			if issue.IsPull {
 				ctx.Flash.Error(ctx.Tr("repo.pulls.is_closed"))
-				ctx.Redirect(issue.Link())
 			} else {
 				ctx.Flash.Error(ctx.Tr("repo.issues.closed_title"))
-				ctx.Redirect(issue.Link())
 			}
-		} else if errors.Is(err, pull_service.ErrUserNotAllowedToMerge) {
+		case errors.Is(err, pull_service.ErrUserNotAllowedToMerge):
 			ctx.Flash.Error(ctx.Tr("repo.pulls.update_not_allowed"))
-			ctx.Redirect(issue.Link())
-		} else if errors.Is(err, pull_service.ErrHasMerged) {
+		case errors.Is(err, pull_service.ErrHasMerged):
 			ctx.Flash.Error(ctx.Tr("repo.pulls.has_merged"))
-			ctx.Redirect(issue.Link())
-		} else if errors.Is(err, pull_service.ErrIsWorkInProgress) {
+		case errors.Is(err, pull_service.ErrIsWorkInProgress):
 			ctx.Flash.Error(ctx.Tr("repo.pulls.no_merge_wip"))
-			ctx.Redirect(issue.Link())
-		} else if errors.Is(err, pull_service.ErrNotMergableState) {
+		case errors.Is(err, pull_service.ErrNotMergableState):
 			ctx.Flash.Error(ctx.Tr("repo.pulls.no_merge_not_ready"))
-			ctx.Redirect(issue.Link())
-		} else if models.IsErrDisallowedToMerge(err) {
+		case models.IsErrDisallowedToMerge(err):
 			ctx.Flash.Error(ctx.Tr("repo.pulls.no_merge_not_ready"))
-			ctx.Redirect(issue.Link())
-		} else if asymkey_service.IsErrWontSign(err) {
-			ctx.Flash.Error(err.Error()) // has not translation ...
-			ctx.Redirect(issue.Link())
-		} else if errors.Is(err, pull_service.ErrDependenciesLeft) {
+		case asymkey_service.IsErrWontSign(err):
+			ctx.Flash.Error(err.Error()) // has no translation ...
+		case errors.Is(err, pull_service.ErrDependenciesLeft):
 			ctx.Flash.Error(ctx.Tr("repo.issues.dependency.pr_close_blocked"))
-			ctx.Redirect(issue.Link())
-		} else {
+		default:
 			ctx.ServerError("WebCheck", err)
+			return
 		}
+
+		ctx.Redirect(issue.Link())
 		return
 	}
 
 	// handle manually-merged mark
-	if manuallMerge {
+	if manualMerge {
 		if err := pull_service.MergedManually(pr, ctx.Doer, ctx.Repo.GitRepo, form.MergeCommitID); err != nil {
-			if models.IsErrInvalidMergeStyle(err) {
+			switch {
+
+			case models.IsErrInvalidMergeStyle(err):
 				ctx.Flash.Error(ctx.Tr("repo.pulls.invalid_merge_option"))
-				ctx.Redirect(issue.Link())
-			} else if strings.Contains(err.Error(), "Wrong commit ID") {
+			case strings.Contains(err.Error(), "Wrong commit ID"):
 				ctx.Flash.Error(ctx.Tr("repo.pulls.wrong_commit_id"))
-				ctx.Redirect(issue.Link())
-			} else {
+			default:
 				ctx.ServerError("MergedManually", err)
+				return
 			}
-			return
 		}
 
 		ctx.Redirect(issue.Link())
diff --git a/services/automerge/automerge.go b/services/automerge/automerge.go
index 15d94e7920..74cfb8da8f 100644
--- a/services/automerge/automerge.go
+++ b/services/automerge/automerge.go
@@ -164,7 +164,7 @@ func getPullRequestsByHeadSHA(ctx context.Context, sha string, repo *repo_model.
 
 func handlePull(pullID int64, sha string) {
 	ctx, _, finished := process.GetManager().AddContext(graceful.GetManager().HammerContext(),
-		fmt.Sprintf("Handle AutoMerge of pull[%d] with sha[%s]", pullID, sha))
+		fmt.Sprintf("Handle AutoMerge of PR[%d] with sha[%s]", pullID, sha))
 	defer finished()
 
 	pr, err := issues_model.GetPullRequestByID(ctx, pullID)
@@ -176,7 +176,7 @@ func handlePull(pullID int64, sha string) {
 	// Check if there is a scheduled pr in the db
 	exists, scheduledPRM, err := pull_model.GetScheduledMergeByPullID(ctx, pr.ID)
 	if err != nil {
-		log.Error("pull[%d] GetScheduledMergeByPullID: %v", pr.ID, err)
+		log.Error("%-v GetScheduledMergeByPullID: %v", pr, err)
 		return
 	}
 	if !exists {
@@ -188,13 +188,13 @@ func handlePull(pullID int64, sha string) {
 	// did not succeed or was not finished yet.
 
 	if err = pr.LoadHeadRepo(ctx); err != nil {
-		log.Error("pull[%d] LoadHeadRepo: %v", pr.ID, err)
+		log.Error("%-v LoadHeadRepo: %v", pr, err)
 		return
 	}
 
 	headGitRepo, err := git.OpenRepository(ctx, pr.HeadRepo.RepoPath())
 	if err != nil {
-		log.Error("OpenRepository: %v", err)
+		log.Error("OpenRepository %-v: %v", pr.HeadRepo, err)
 		return
 	}
 	defer headGitRepo.Close()
@@ -202,40 +202,40 @@ func handlePull(pullID int64, sha string) {
 	headBranchExist := headGitRepo.IsBranchExist(pr.HeadBranch)
 
 	if pr.HeadRepo == nil || !headBranchExist {
-		log.Warn("Head branch of auto merge pr does not exist [HeadRepoID: %d, Branch: %s, PR ID: %d]", pr.HeadRepoID, pr.HeadBranch, pr.ID)
+		log.Warn("Head branch of auto merge %-v does not exist [HeadRepoID: %d, Branch: %s]", pr, pr.HeadRepoID, pr.HeadBranch)
 		return
 	}
 
 	// Check if all checks succeeded
 	pass, err := pull_service.IsPullCommitStatusPass(ctx, pr)
 	if err != nil {
-		log.Error("IsPullCommitStatusPass: %v", err)
+		log.Error("%-v IsPullCommitStatusPass: %v", pr, err)
 		return
 	}
 	if !pass {
-		log.Info("Scheduled auto merge pr has unsuccessful status checks [PullID: %d]", pr.ID)
+		log.Info("Scheduled auto merge %-v has unsuccessful status checks", pr)
 		return
 	}
 
 	// Merge if all checks succeeded
 	doer, err := user_model.GetUserByID(ctx, scheduledPRM.DoerID)
 	if err != nil {
-		log.Error("GetUserByIDCtx: %v", err)
+		log.Error("Unable to get scheduled User[%d]: %v", scheduledPRM.DoerID, err)
 		return
 	}
 
 	perm, err := access_model.GetUserRepoPermission(ctx, pr.HeadRepo, doer)
 	if err != nil {
-		log.Error("GetUserRepoPermission: %v", err)
+		log.Error("GetUserRepoPermission %-v: %v", pr.HeadRepo, err)
 		return
 	}
 
 	if err := pull_service.CheckPullMergable(ctx, doer, &perm, pr, false, false); err != nil {
 		if errors.Is(pull_service.ErrUserNotAllowedToMerge, err) {
-			log.Info("PR %d was scheduled to automerge by an unauthorized user", pr.ID)
+			log.Info("%-v was scheduled to automerge by an unauthorized user", pr)
 			return
 		}
-		log.Error("pull[%d] CheckPullMergable: %v", pr.ID, err)
+		log.Error("%-v CheckPullMergable: %v", pr, err)
 		return
 	}
 
@@ -244,13 +244,13 @@ func handlePull(pullID int64, sha string) {
 		baseGitRepo = headGitRepo
 	} else {
 		if err = pr.LoadBaseRepo(ctx); err != nil {
-			log.Error("LoadBaseRepo: %v", err)
+			log.Error("%-v LoadBaseRepo: %v", pr, err)
 			return
 		}
 
 		baseGitRepo, err = git.OpenRepository(ctx, pr.BaseRepo.RepoPath())
 		if err != nil {
-			log.Error("OpenRepository: %v", err)
+			log.Error("OpenRepository %-v: %v", pr.BaseRepo, err)
 			return
 		}
 		defer baseGitRepo.Close()
diff --git a/services/pull/check.go b/services/pull/check.go
index db86378909..481491c73b 100644
--- a/services/pull/check.go
+++ b/services/pull/check.go
@@ -8,7 +8,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"os"
 	"strconv"
 	"strings"
 
@@ -27,7 +26,6 @@ import (
 	"code.gitea.io/gitea/modules/process"
 	"code.gitea.io/gitea/modules/queue"
 	"code.gitea.io/gitea/modules/timeutil"
-	"code.gitea.io/gitea/modules/util"
 	asymkey_service "code.gitea.io/gitea/services/asymkey"
 )
 
@@ -50,14 +48,14 @@ func AddToTaskQueue(pr *issues_model.PullRequest) {
 		pr.Status = issues_model.PullRequestStatusChecking
 		err := pr.UpdateColsIfNotMerged(db.DefaultContext, "status")
 		if err != nil {
-			log.Error("AddToTaskQueue.UpdateCols[%d].(add to queue): %v", pr.ID, err)
+			log.Error("AddToTaskQueue(%-v).UpdateCols.(add to queue): %v", pr, err)
 		} else {
-			log.Trace("Adding PR ID: %d to the test pull requests queue", pr.ID)
+			log.Trace("Adding %-v to the test pull requests queue", pr)
 		}
 		return err
 	})
 	if err != nil && err != queue.ErrAlreadyInQueue {
-		log.Error("Error adding prID %d to the test pull requests queue: %v", pr.ID, err)
+		log.Error("Error adding %-v to the test pull requests queue: %v", pr, err)
 	}
 }
 
@@ -69,12 +67,14 @@ func CheckPullMergable(stdCtx context.Context, doer *user_model.User, perm *acce
 		}
 
 		if err := pr.LoadIssue(ctx); err != nil {
+			log.Error("Unable to load issue[%d] for %-v: %v", pr.IssueID, pr, err)
 			return err
 		} else if pr.Issue.IsClosed {
 			return ErrIsClosed
 		}
 
 		if allowedMerge, err := IsUserAllowedToMerge(ctx, pr, *perm, doer); err != nil {
+			log.Error("Error whilst checking if %-v is allowed to merge %-v: %v", doer, pr, err)
 			return err
 		} else if !allowedMerge {
 			return ErrUserNotAllowedToMerge
@@ -98,15 +98,19 @@ func CheckPullMergable(stdCtx context.Context, doer *user_model.User, perm *acce
 		}
 
 		if err := CheckPullBranchProtections(ctx, pr, false); err != nil {
-			if models.IsErrDisallowedToMerge(err) {
-				if force {
-					if isRepoAdmin, err2 := access_model.IsUserRepoAdmin(ctx, pr.BaseRepo, doer); err2 != nil {
-						return err2
-					} else if !isRepoAdmin {
-						return err
-					}
-				}
-			} else {
+			if !models.IsErrDisallowedToMerge(err) {
+				log.Error("Error whilst checking pull branch protection for %-v: %v", pr, err)
+				return err
+			}
+
+			if !force {
+				return err
+			}
+
+			if isRepoAdmin, err2 := access_model.IsUserRepoAdmin(ctx, pr.BaseRepo, doer); err2 != nil {
+				log.Error("Unable to check if %-v is a repo admin in %-v: %v", doer, pr.BaseRepo, err2)
+				return err2
+			} else if !isRepoAdmin {
 				return err
 			}
 		}
@@ -144,7 +148,7 @@ func isSignedIfRequired(ctx context.Context, pr *issues_model.PullRequest, doer
 // checkAndUpdateStatus checks if pull request is possible to leaving checking status,
 // and set to be either conflict or mergeable.
 func checkAndUpdateStatus(ctx context.Context, pr *issues_model.PullRequest) {
-	// Status is not changed to conflict means mergeable.
+	// If status has not been changed to conflict by testPatch then we are mergeable
 	if pr.Status == issues_model.PullRequestStatusChecking {
 		pr.Status = issues_model.PullRequestStatusMergeable
 	}
@@ -152,79 +156,69 @@ func checkAndUpdateStatus(ctx context.Context, pr *issues_model.PullRequest) {
 	// Make sure there is no waiting test to process before leaving the checking status.
 	has, err := prPatchCheckerQueue.Has(strconv.FormatInt(pr.ID, 10))
 	if err != nil {
-		log.Error("Unable to check if the queue is waiting to reprocess pr.ID %d. Error: %v", pr.ID, err)
+		log.Error("Unable to check if the queue is waiting to reprocess %-v. Error: %v", pr, err)
 	}
 
-	if !has {
-		if err := pr.UpdateColsIfNotMerged(ctx, "merge_base", "status", "conflicted_files", "changed_protected_files"); err != nil {
-			log.Error("Update[%d]: %v", pr.ID, err)
-		}
+	if has {
+		log.Trace("Not updating status for %-v as it is due to be rechecked", pr)
+		return
+	}
+
+	if err := pr.UpdateColsIfNotMerged(ctx, "merge_base", "status", "conflicted_files", "changed_protected_files"); err != nil {
+		log.Error("Update[%-v]: %v", pr, err)
 	}
 }
 
-// getMergeCommit checks if a pull request got merged
+// getMergeCommit checks if a pull request has been merged
 // Returns the git.Commit of the pull request if merged
 func getMergeCommit(ctx context.Context, pr *issues_model.PullRequest) (*git.Commit, error) {
-	if pr.BaseRepo == nil {
-		var err error
-		pr.BaseRepo, err = repo_model.GetRepositoryByID(ctx, pr.BaseRepoID)
-		if err != nil {
-			return nil, fmt.Errorf("GetRepositoryByID: %w", err)
-		}
-	}
-
-	indexTmpPath, err := os.MkdirTemp(os.TempDir(), "gitea-"+pr.BaseRepo.Name)
-	if err != nil {
-		return nil, fmt.Errorf("Failed to create temp dir for repository %s: %w", pr.BaseRepo.RepoPath(), err)
+	if err := pr.LoadBaseRepo(ctx); err != nil {
+		return nil, fmt.Errorf("unable to load base repo for %s: %w", pr, err)
 	}
-	defer func() {
-		if err := util.RemoveAll(indexTmpPath); err != nil {
-			log.Warn("Unable to remove temporary index path: %s: Error: %v", indexTmpPath, err)
-		}
-	}()
 
-	headFile := pr.GetGitRefName()
+	prHeadRef := pr.GetGitRefName()
 
-	// Check if a pull request is merged into BaseBranch
-	_, _, err = git.NewCommand(ctx, "merge-base", "--is-ancestor").AddDynamicArguments(headFile, pr.BaseBranch).
-		RunStdString(&git.RunOpts{Dir: pr.BaseRepo.RepoPath(), Env: []string{"GIT_INDEX_FILE=" + indexTmpPath, "GIT_DIR=" + pr.BaseRepo.RepoPath()}})
-	if err != nil {
-		// Errors are signaled by a non-zero status that is not 1
+	// Check if the pull request is merged into BaseBranch
+	if _, _, err := git.NewCommand(ctx, "merge-base", "--is-ancestor").
+		AddDynamicArguments(prHeadRef, pr.BaseBranch).
+		RunStdString(&git.RunOpts{Dir: pr.BaseRepo.RepoPath()}); err != nil {
 		if strings.Contains(err.Error(), "exit status 1") {
+			// prHeadRef is not an ancestor of the base branch
 			return nil, nil
 		}
-		return nil, fmt.Errorf("git merge-base --is-ancestor: %w", err)
+		// Errors are signaled by a non-zero status that is not 1
+		return nil, fmt.Errorf("%-v git merge-base --is-ancestor: %w", pr, err)
 	}
 
-	commitIDBytes, err := os.ReadFile(pr.BaseRepo.RepoPath() + "/" + headFile)
+	// If merge-base successfully exits then prHeadRef is an ancestor of pr.BaseBranch
+
+	// Find the head commit id
+	prHeadCommitID, err := git.GetFullCommitID(ctx, pr.BaseRepo.RepoPath(), prHeadRef)
 	if err != nil {
-		return nil, fmt.Errorf("ReadFile(%s): %w", headFile, err)
+		return nil, fmt.Errorf("GetFullCommitID(%s) in %s: %w", prHeadRef, pr.BaseRepo.FullName(), err)
 	}
-	commitID := string(commitIDBytes)
-	if len(commitID) < git.SHAFullLength {
-		return nil, fmt.Errorf(`ReadFile(%s): invalid commit-ID "%s"`, headFile, commitID)
-	}
-	cmd := commitID[:git.SHAFullLength] + ".." + pr.BaseBranch
 
 	// Get the commit from BaseBranch where the pull request got merged
-	mergeCommit, _, err := git.NewCommand(ctx, "rev-list", "--ancestry-path", "--merges", "--reverse").AddDynamicArguments(cmd).
-		RunStdString(&git.RunOpts{Dir: "", Env: []string{"GIT_INDEX_FILE=" + indexTmpPath, "GIT_DIR=" + pr.BaseRepo.RepoPath()}})
+	mergeCommit, _, err := git.NewCommand(ctx, "rev-list", "--ancestry-path", "--merges", "--reverse").
+		AddDynamicArguments(prHeadCommitID + ".." + pr.BaseBranch).
+		RunStdString(&git.RunOpts{Dir: pr.BaseRepo.RepoPath()})
 	if err != nil {
 		return nil, fmt.Errorf("git rev-list --ancestry-path --merges --reverse: %w", err)
 	} else if len(mergeCommit) < git.SHAFullLength {
 		// PR was maybe fast-forwarded, so just use last commit of PR
-		mergeCommit = commitID[:git.SHAFullLength]
+		mergeCommit = prHeadCommitID
 	}
+	mergeCommit = strings.TrimSpace(mergeCommit)
 
 	gitRepo, err := git.OpenRepository(ctx, pr.BaseRepo.RepoPath())
 	if err != nil {
-		return nil, fmt.Errorf("OpenRepository: %w", err)
+		return nil, fmt.Errorf("%-v OpenRepository: %w", pr.BaseRepo, err)
 	}
 	defer gitRepo.Close()
 
-	commit, err := gitRepo.GetCommit(mergeCommit[:git.SHAFullLength])
+	commit, err := gitRepo.GetCommit(mergeCommit)
 	if err != nil {
-		return nil, fmt.Errorf("GetMergeCommit[%v]: %w", mergeCommit[:git.SHAFullLength], err)
+		return nil, fmt.Errorf("GetMergeCommit[%s]: %w", mergeCommit, err)
 	}
 
 	return commit, nil
@@ -234,7 +228,7 @@ func getMergeCommit(ctx context.Context, pr *issues_model.PullRequest) (*git.Com
 // When a pull request got manually merged mark the pull request as merged
 func manuallyMerged(ctx context.Context, pr *issues_model.PullRequest) bool {
 	if err := pr.LoadBaseRepo(ctx); err != nil {
-		log.Error("PullRequest[%d].LoadBaseRepo: %v", pr.ID, err)
+		log.Error("%-v LoadBaseRepo: %v", pr, err)
 		return false
 	}
 
@@ -244,47 +238,50 @@ func manuallyMerged(ctx context.Context, pr *issues_model.PullRequest) bool {
 			return false
 		}
 	} else {
-		log.Error("PullRequest[%d].BaseRepo.GetUnit(unit.TypePullRequests): %v", pr.ID, err)
+		log.Error("%-v BaseRepo.GetUnit(unit.TypePullRequests): %v", pr, err)
 		return false
 	}
 
 	commit, err := getMergeCommit(ctx, pr)
 	if err != nil {
-		log.Error("PullRequest[%d].getMergeCommit: %v", pr.ID, err)
+		log.Error("%-v getMergeCommit: %v", pr, err)
+		return false
+	}
+
+	if commit == nil {
+		// no merge commit found
 		return false
 	}
-	if commit != nil {
-		pr.MergedCommitID = commit.ID.String()
-		pr.MergedUnix = timeutil.TimeStamp(commit.Author.When.Unix())
-		pr.Status = issues_model.PullRequestStatusManuallyMerged
-		merger, _ := user_model.GetUserByEmail(commit.Author.Email)
-
-		// When the commit author is unknown set the BaseRepo owner as merger
-		if merger == nil {
-			if pr.BaseRepo.Owner == nil {
-				if err = pr.BaseRepo.GetOwner(ctx); err != nil {
-					log.Error("BaseRepo.GetOwner[%d]: %v", pr.ID, err)
-					return false
-				}
+
+	pr.MergedCommitID = commit.ID.String()
+	pr.MergedUnix = timeutil.TimeStamp(commit.Author.When.Unix())
+	pr.Status = issues_model.PullRequestStatusManuallyMerged
+	merger, _ := user_model.GetUserByEmail(commit.Author.Email)
+
+	// When the commit author is unknown set the BaseRepo owner as merger
+	if merger == nil {
+		if pr.BaseRepo.Owner == nil {
+			if err = pr.BaseRepo.GetOwner(ctx); err != nil {
+				log.Error("%-v BaseRepo.GetOwner: %v", pr, err)
+				return false
 			}
-			merger = pr.BaseRepo.Owner
 		}
-		pr.Merger = merger
-		pr.MergerID = merger.ID
+		merger = pr.BaseRepo.Owner
+	}
+	pr.Merger = merger
+	pr.MergerID = merger.ID
 
-		if merged, err := pr.SetMerged(ctx); err != nil {
-			log.Error("PullRequest[%d].setMerged : %v", pr.ID, err)
-			return false
-		} else if !merged {
-			return false
-		}
+	if merged, err := pr.SetMerged(ctx); err != nil {
+		log.Error("%-v setMerged : %v", pr, err)
+		return false
+	} else if !merged {
+		return false
+	}
 
-		notification.NotifyMergePullRequest(ctx, merger, pr)
+	notification.NotifyMergePullRequest(ctx, merger, pr)
 
-		log.Info("manuallyMerged[%d]: Marked as manually merged into %s/%s by commit id: %s", pr.ID, pr.BaseRepo.Name, pr.BaseBranch, commit.ID.String())
-		return true
-	}
-	return false
+	log.Info("manuallyMerged[%-v]: Marked as manually merged into %s/%s by commit id: %s", pr, pr.BaseRepo.Name, pr.BaseBranch, commit.ID.String())
+	return true
 }
 
 // InitializePullRequests checks and tests untested patches of pull requests.
@@ -300,10 +297,10 @@ func InitializePullRequests(ctx context.Context) {
 			return
 		default:
 			if err := prPatchCheckerQueue.PushFunc(strconv.FormatInt(prID, 10), func() error {
-				log.Trace("Adding PR ID: %d to the pull requests patch checking queue", prID)
+				log.Trace("Adding PR[%d] to the pull requests patch checking queue", prID)
 				return nil
 			}); err != nil {
-				log.Error("Error adding prID: %s to the pull requests patch checking queue %v", prID, err)
+				log.Error("Error adding PR[%d] to the pull requests patch checking queue %v", prID, err)
 			}
 		}
 	}
@@ -327,23 +324,30 @@ func testPR(id int64) {
 
 	pr, err := issues_model.GetPullRequestByID(ctx, id)
 	if err != nil {
-		log.Error("GetPullRequestByID[%d]: %v", id, err)
+		log.Error("Unable to GetPullRequestByID[%d] for testPR: %v", id, err)
 		return
 	}
 
+	log.Trace("Testing %-v", pr)
+	defer func() {
+		log.Trace("Done testing %-v (status: %s)", pr, pr.Status)
+	}()
+
 	if pr.HasMerged {
+		log.Trace("%-v is already merged (status: %s, merge commit: %s)", pr, pr.Status, pr.MergedCommitID)
 		return
 	}
 
 	if manuallyMerged(ctx, pr) {
+		log.Trace("%-v is manually merged (status: %s, merge commit: %s)", pr, pr.Status, pr.MergedCommitID)
 		return
 	}
 
 	if err := TestPatch(pr); err != nil {
-		log.Error("testPatch[%d]: %v", pr.ID, err)
+		log.Error("testPatch[%-v]: %v", pr, err)
 		pr.Status = issues_model.PullRequestStatusError
 		if err := pr.UpdateCols("status"); err != nil {
-			log.Error("update pr [%d] status to PullRequestStatusError failed: %v", pr.ID, err)
+			log.Error("update pr [%-v] status to PullRequestStatusError failed: %v", pr, err)
 		}
 		return
 	}
diff --git a/services/pull/patch.go b/services/pull/patch.go
index 26a72a7371..a3084196bb 100644
--- a/services/pull/patch.go
+++ b/services/pull/patch.go
@@ -60,7 +60,7 @@ var patchErrorSuffices = []string{
 
 // TestPatch will test whether a simple patch will apply
 func TestPatch(pr *issues_model.PullRequest) error {
-	ctx, _, finished := process.GetManager().AddContext(graceful.GetManager().HammerContext(), fmt.Sprintf("TestPatch: Repo[%d]#%d", pr.BaseRepoID, pr.Index))
+	ctx, _, finished := process.GetManager().AddContext(graceful.GetManager().HammerContext(), fmt.Sprintf("TestPatch: %s", pr))
 	defer finished()
 
 	// Clone base repo.