Tagger can be empty, as can Commit and Author - tolerate this (#15835) (#15839)

Backport #15835

Unfortunately some old repositories can have tags with empty Tagger, Commit
or Author. Go-Git variants will always have empty values for these whereas
the native git variant leaves them at nil. The simplest solution is just to
always have these set to empty Signatures.

v156 migration also makes the incorrect assumption that these cannot be empty.
Therefore add some handling to this and add logging and adjust broken
logging elsewhere in this migration.

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>

models/migrations/v156.go

@@ -88,7 +88,7 @@ func fixPublisherIDforTagReleases(x *xorm.Engine) error {
 				repo = new(Repository)
 				has, err := sess.ID(release.RepoID).Get(repo)
 				if err != nil {
-					log.Error("Error whilst loading repository[%d] for release[%d] with tag name %s", release.RepoID, release.ID, release.TagName)
+					log.Error("Error whilst loading repository[%d] for release[%d] with tag name %s. Error: %v", release.RepoID, release.ID, release.TagName, err)
 					return err
 				} else if !has {
 					log.Warn("Release[%d] is orphaned and refers to non-existing repository %d", release.ID, release.RepoID)
@@ -105,13 +105,13 @@ func fixPublisherIDforTagReleases(x *xorm.Engine) error {
 					}
 
 					if _, err := sess.ID(release.RepoID).Get(repo); err != nil {
-						log.Error("Error whilst loading repository[%d] for release[%d] with tag name %s", release.RepoID, release.ID, release.TagName)
+						log.Error("Error whilst loading repository[%d] for release[%d] with tag name %s. Error: %v", release.RepoID, release.ID, release.TagName, err)
 						return err
 					}
 				}
 				gitRepo, err = git.OpenRepository(repoPath(repo.OwnerName, repo.Name))
 				if err != nil {
-					log.Error("Error whilst opening git repo for %-v", repo)
+					log.Error("Error whilst opening git repo for [%d]%s/%s. Error: %v", repo.ID, repo.OwnerName, repo.Name, err)
 					return err
 				}
 			}
@@ -119,18 +119,36 @@ func fixPublisherIDforTagReleases(x *xorm.Engine) error {
 			commit, err := gitRepo.GetTagCommit(release.TagName)
 			if err != nil {
 				if git.IsErrNotExist(err) {
-					log.Warn("Unable to find commit %s for Tag: %s in %-v. Cannot update publisher ID.", err.(git.ErrNotExist).ID, release.TagName, repo)
+					log.Warn("Unable to find commit %s for Tag: %s in [%d]%s/%s. Cannot update publisher ID.", err.(git.ErrNotExist).ID, release.TagName, repo.ID, repo.OwnerName, repo.Name)
 					continue
 				}
-				log.Error("Error whilst getting commit for Tag: %s in %-v.", release.TagName, repo)
+				log.Error("Error whilst getting commit for Tag: %s in [%d]%s/%s. Error: %v", release.TagName, repo.ID, repo.OwnerName, repo.Name, err)
 				return fmt.Errorf("GetTagCommit: %v", err)
 			}
 
+			if commit.Author.Email == "" {
+				log.Warn("Tag: %s in Repo[%d]%s/%s does not have a tagger.", release.TagName, repo.ID, repo.OwnerName, repo.Name)
+				commit, err = gitRepo.GetCommit(commit.ID.String())
+				if err != nil {
+					if git.IsErrNotExist(err) {
+						log.Warn("Unable to find commit %s for Tag: %s in [%d]%s/%s. Cannot update publisher ID.", err.(git.ErrNotExist).ID, release.TagName, repo.ID, repo.OwnerName, repo.Name)
+						continue
+					}
+					log.Error("Error whilst getting commit for Tag: %s in [%d]%s/%s. Error: %v", release.TagName, repo.ID, repo.OwnerName, repo.Name, err)
+					return fmt.Errorf("GetCommit: %v", err)
+				}
+			}
+
+			if commit.Author.Email == "" {
+				log.Warn("Tag: %s in Repo[%d]%s/%s does not have a Tagger and its underlying commit does not have an Author either!", release.TagName, repo.ID, repo.OwnerName, repo.Name)
+				continue
+			}
+
 			if user == nil || !strings.EqualFold(user.Email, commit.Author.Email) {
 				user = new(User)
 				_, err = sess.Where("email=?", commit.Author.Email).Get(user)
 				if err != nil {
-					log.Error("Error whilst getting commit author by email: %s for Tag: %s in %-v.", commit.Author.Email, release.TagName, repo)
+					log.Error("Error whilst getting commit author by email: %s for Tag: %s in [%d]%s/%s. Error: %v", commit.Author.Email, release.TagName, repo.ID, repo.OwnerName, repo.Name, err)
 					return err
 				}
 
@@ -143,7 +161,7 @@ func fixPublisherIDforTagReleases(x *xorm.Engine) error {
 
 			release.PublisherID = user.ID
 			if _, err := sess.ID(release.ID).Cols("publisher_id").Update(release); err != nil {
-				log.Error("Error whilst updating publisher[%d] for release[%d] with tag name %s", release.PublisherID, release.ID, release.TagName)
+				log.Error("Error whilst updating publisher[%d] for release[%d] with tag name %s. Error: %v", release.PublisherID, release.ID, release.TagName, err)
 				return err
 			}
 		}

modules/git/commit_reader.go

@@ -17,7 +17,9 @@ import (
 // If used as part of a cat-file --batch stream you need to limit the reader to the correct size
 func CommitFromReader(gitRepo *Repository, sha SHA1, reader io.Reader) (*Commit, error) {
 	commit := &Commit{
-		ID: sha,
+		ID:        sha,
+		Author:    &Signature{},
+		Committer: &Signature{},
 	}
 
 	payloadSB := new(strings.Builder)

modules/git/tag.go

@@ -35,6 +35,7 @@ func (tag *Tag) Commit() (*Commit, error) {
 // \n\n separate headers from message
 func parseTagData(data []byte) (*Tag, error) {
 	tag := new(Tag)
+	tag.Tagger = &Signature{}
 	// we now have the contents of the commit object. Let's investigate...
 	nextline := 0
 l: