Split migrations folder (#21549)

There are too many files in `models/migrations` folder so that I split
them into sub folders.

models/migrations/v1_12/v136.go

@@ -0,0 +1,126 @@
+// Copyright 2020 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 v1_12 //nolint
+
+import (
+	"fmt"
+	"math"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/graceful"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+
+	"xorm.io/xorm"
+)
+
+func AddCommitDivergenceToPulls(x *xorm.Engine) error {
+	type Repository struct {
+		ID        int64 `xorm:"pk autoincr"`
+		OwnerID   int64 `xorm:"UNIQUE(s) index"`
+		OwnerName string
+		LowerName string `xorm:"UNIQUE(s) INDEX NOT NULL"`
+		Name      string `xorm:"INDEX NOT NULL"`
+	}
+
+	type PullRequest struct {
+		ID      int64 `xorm:"pk autoincr"`
+		IssueID int64 `xorm:"INDEX"`
+		Index   int64
+
+		CommitsAhead  int
+		CommitsBehind int
+
+		BaseRepoID int64 `xorm:"INDEX"`
+		BaseBranch string
+
+		HasMerged      bool   `xorm:"INDEX"`
+		MergedCommitID string `xorm:"VARCHAR(40)"`
+	}
+
+	if err := x.Sync2(new(PullRequest)); err != nil {
+		return fmt.Errorf("Sync2: %w", err)
+	}
+
+	last := 0
+	migrated := 0
+
+	batchSize := setting.Database.IterateBufferSize
+	sess := x.NewSession()
+	defer sess.Close()
+
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+	count, err := sess.Where("has_merged = ?", false).Count(new(PullRequest))
+	if err != nil {
+		return err
+	}
+	log.Info("%d Unmerged Pull Request(s) to migrate ...", count)
+
+	for {
+		if err := sess.Begin(); err != nil {
+			return err
+		}
+		results := make([]*PullRequest, 0, batchSize)
+		err := sess.Where("has_merged = ?", false).OrderBy("id").Limit(batchSize, last).Find(&results)
+		if err != nil {
+			return err
+		}
+		if len(results) == 0 {
+			break
+		}
+		last += batchSize
+
+		for _, pr := range results {
+			baseRepo := &Repository{ID: pr.BaseRepoID}
+			has, err := x.Table("repository").Get(baseRepo)
+			if err != nil {
+				return fmt.Errorf("Unable to get base repo %d %w", pr.BaseRepoID, err)
+			}
+			if !has {
+				log.Error("Missing base repo with id %d for PR ID %d", pr.BaseRepoID, pr.ID)
+				continue
+			}
+			userPath := filepath.Join(setting.RepoRootPath, strings.ToLower(baseRepo.OwnerName))
+			repoPath := filepath.Join(userPath, strings.ToLower(baseRepo.Name)+".git")
+
+			gitRefName := fmt.Sprintf("refs/pull/%d/head", pr.Index)
+
+			divergence, err := git.GetDivergingCommits(graceful.GetManager().HammerContext(), repoPath, pr.BaseBranch, gitRefName)
+			if err != nil {
+				log.Warn("Could not recalculate Divergence for pull: %d", pr.ID)
+				pr.CommitsAhead = 0
+				pr.CommitsBehind = 0
+			}
+			pr.CommitsAhead = divergence.Ahead
+			pr.CommitsBehind = divergence.Behind
+
+			if _, err = sess.ID(pr.ID).Cols("commits_ahead", "commits_behind").Update(pr); err != nil {
+				return fmt.Errorf("Update Cols: %w", err)
+			}
+			migrated++
+		}
+
+		if err := sess.Commit(); err != nil {
+			return err
+		}
+		select {
+		case <-ticker.C:
+			log.Info(
+				"%d/%d (%2.0f%%) Pull Request(s) migrated in %d batches. %d PRs Remaining ...",
+				migrated,
+				count,
+				float64(migrated)/float64(count)*100,
+				int(math.Ceil(float64(migrated)/float64(batchSize))),
+				count-int64(migrated))
+		default:
+		}
+	}
+	log.Info("Completed migrating %d Pull Request(s) in: %d batches", count, int(math.Ceil(float64(migrated)/float64(batchSize))))
+	return nil
+}