Support importing comment types (#22510)

This commit adds support for specifying comment types when importing
with `gitea restore-repo`. It makes it possible to import issue changes,
such as "title changed" or "assigned user changed".

An earlier version of this pull request was made by Matti Ranta, in
https://future.projects.blender.org/blender-migration/gitea-bf/pulls/3

There are two changes with regard to Matti's original code:

1. The comment type was an `int64` in Matti's code, and is now using a
string. This makes it possible to use `comment_type: title`, which is
more reliable and future-proof than an index into an internal list in
the Gitea Go code.

2. Matti's code also had support for including labels, but in a way that
would require knowing the database ID of the labels before the import
even starts, which is impossible. This can be solved by using label
names instead of IDs; for simplicity I I left that out of this PR.

4 files changed, 39 insertions, 2 deletions

diff --git a/models/issues/comment.go b/models/issues/comment.go
index 87e6b0a229..91dc128277 100644
--- a/models/issues/comment.go
+++ b/models/issues/comment.go
@@ -175,6 +175,15 @@ func (t CommentType) String() string {
 	return commentStrings[t]
 }
 
+func AsCommentType(typeName string) CommentType {
+	for index, name := range commentStrings {
+		if typeName == name {
+			return CommentType(index)
+		}
+	}
+	return CommentTypeUnknown
+}
+
 // RoleDescriptor defines comment tag type
 type RoleDescriptor int
 
diff --git a/models/issues/comment_test.go b/models/issues/comment_test.go
index 0d0570ae34..f1232729f1 100644
--- a/models/issues/comment_test.go
+++ b/models/issues/comment_test.go
@@ -62,3 +62,10 @@ func TestFetchCodeComments(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Len(t, res, 1)
 }
+
+func TestAsCommentType(t *testing.T) {
+	assert.Equal(t, issues_model.CommentTypeUnknown, issues_model.AsCommentType(""))
+	assert.Equal(t, issues_model.CommentTypeUnknown, issues_model.AsCommentType("nonsense"))
+	assert.Equal(t, issues_model.CommentTypeComment, issues_model.AsCommentType("comment"))
+	assert.Equal(t, issues_model.CommentTypePRUnScheduledToAutoMerge, issues_model.AsCommentType("pull_cancel_scheduled_merge"))
+}
diff --git a/modules/migration/comment.go b/modules/migration/comment.go
index 27ecaa830a..f994e972ed 100644
--- a/modules/migration/comment.go
+++ b/modules/migration/comment.go
@@ -17,6 +17,7 @@ type Commentable interface {
 type Comment struct {
 	IssueIndex  int64 `yaml:"issue_index"`
 	Index       int64
+	CommentType string `yaml:"comment_type"` // see `commentStrings` in models/issues/comment.go
 	PosterID    int64  `yaml:"poster_id"`
 	PosterName  string `yaml:"poster_name"`
 	PosterEmail string `yaml:"poster_email"`
@@ -24,6 +25,7 @@ type Comment struct {
 	Updated     time.Time
 	Content     string
 	Reactions   []*Reaction
+	Meta        map[string]interface{} `yaml:"meta,omitempty"` // see models/issues/comment.go for fields in Comment struct
 }
 
 // GetExternalName ExternalUserMigrated interface
diff --git a/services/migrations/gitea_uploader.go b/services/migrations/gitea_uploader.go
index 23aa4ac2ca..f43c7378b8 100644
--- a/services/migrations/gitea_uploader.go
+++ b/services/migrations/gitea_uploader.go
@@ -454,15 +454,34 @@ func (g *GiteaLocalUploader) CreateComments(comments ...*base.Comment) error {
 		if comment.Updated.IsZero() {
 			comment.Updated = comment.Created
 		}
-
+		if comment.CommentType == "" {
+			// if type field is missing, then assume a normal comment
+			comment.CommentType = issues_model.CommentTypeComment.String()
+		}
 		cm := issues_model.Comment{
 			IssueID:     issue.ID,
-			Type:        issues_model.CommentTypeComment,
+			Type:        issues_model.AsCommentType(comment.CommentType),
 			Content:     comment.Content,
 			CreatedUnix: timeutil.TimeStamp(comment.Created.Unix()),
 			UpdatedUnix: timeutil.TimeStamp(comment.Updated.Unix()),
 		}
 
+		switch cm.Type {
+		case issues_model.CommentTypeAssignees:
+			cm.AssigneeID = comment.Meta["AssigneeID"].(int64)
+			if comment.Meta["RemovedAssigneeID"] != nil {
+				cm.RemovedAssignee = true
+			}
+		case issues_model.CommentTypeChangeTitle:
+			if comment.Meta["OldTitle"] != nil {
+				cm.OldTitle = fmt.Sprintf("%s", comment.Meta["OldTitle"])
+			}
+			if comment.Meta["NewTitle"] != nil {
+				cm.NewTitle = fmt.Sprintf("%s", comment.Meta["NewTitle"])
+			}
+		default:
+		}
+
 		if err := g.remapUser(comment, &cm); err != nil {
 			return err
 		}