Improvements to content history (#17746)

* Improvements to content history

* initialize content history when making an edit to an old item created before the introduction of content history
* show edit history for code comments on pull request files tab

* Fix a flaw in keepLimitedContentHistory
Fix a flaw in keepLimitedContentHistory, the first and the last should never be deleted

* Remove obsolete eager initialization of content history

1 files changed, 13 insertions, 7 deletions

diff --git a/models/issue.go b/models/issue.go
index 6de7c3204b..7aab8b9399 100644
--- a/models/issue.go
+++ b/models/issue.go
@@ -824,14 +824,25 @@ func (issue *Issue) UpdateAttachments(uuids []string) (err error) {
 
 // ChangeContent changes issue content, as the given user.
 func (issue *Issue) ChangeContent(doer *User, content string) (err error) {
-	issue.Content = content
-
 	ctx, committer, err := db.TxContext()
 	if err != nil {
 		return err
 	}
 	defer committer.Close()
 
+	hasContentHistory, err := issues.HasIssueContentHistory(ctx, issue.ID, 0)
+	if err != nil {
+		return fmt.Errorf("HasIssueContentHistory: %v", err)
+	}
+	if !hasContentHistory {
+		if err = issues.SaveIssueContentHistory(db.GetEngine(ctx), issue.PosterID, issue.ID, 0,
+			issue.CreatedUnix, issue.Content, true); err != nil {
+			return fmt.Errorf("SaveIssueContentHistory: %v", err)
+		}
+	}
+
+	issue.Content = content
+
 	if err = updateIssueCols(db.GetEngine(ctx), issue, "content"); err != nil {
 		return fmt.Errorf("UpdateIssueCols: %v", err)
 	}
@@ -1012,11 +1023,6 @@ func newIssue(ctx context.Context, doer *User, opts NewIssueOptions) (err error)
 		return err
 	}
 
-	if err = issues.SaveIssueContentHistory(e, doer.ID, opts.Issue.ID, 0,
-		timeutil.TimeStampNow(), opts.Issue.Content, true); err != nil {
-		return err
-	}
-
 	return opts.Issue.addCrossReferences(ctx, doer, false)
 }