Add missing `X-Total-Count` and fix some related bugs (#17968)

* Add missing `X-Total-Count` and fix some related bugs

Adds `X-Total-Count` header to APIs that return a list but doesn't have it yet.
Fixed bugs:
* not returned after reporting error (https://github.com/qwerty287/gitea/blob/39eb82446c6fe5da3d79124e1f701f3795625b69/routers/api/v1/user/star.go#L70)
* crash with index out of bounds, API issue/issueSubscriptions

I also found various endpoints that return lists but do not apply/support pagination yet:
```
/repos/{owner}/{repo}/issues/{index}/labels
/repos/{owner}/{repo}/issues/comments/{id}/reactions
/repos/{owner}/{repo}/branch_protections
/repos/{owner}/{repo}/contents
/repos/{owner}/{repo}/hooks/git
/repos/{owner}/{repo}/issue_templates
/repos/{owner}/{repo}/releases/{id}/assets
/repos/{owner}/{repo}/reviewers
/repos/{owner}/{repo}/teams
/user/emails
/users/{username}/heatmap
```
If this is not expected, an new issue should be opened.

Closes #13043

* fmt

* Update routers/api/v1/repo/issue_subscription.go

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

* Use FindAndCount

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
Co-authored-by: 6543 <6543@obermui.de>

1 files changed, 10 insertions, 8 deletions

diff --git a/models/issue_reaction.go b/models/issue_reaction.go
index 4072733a1c..2e0ab07db7 100644
--- a/models/issue_reaction.go
+++ b/models/issue_reaction.go
@@ -71,7 +71,7 @@ func (opts *FindReactionsOptions) toConds() builder.Cond {
 }
 
 // FindCommentReactions returns a ReactionList of all reactions from an comment
-func FindCommentReactions(comment *Comment) (ReactionList, error) {
+func FindCommentReactions(comment *Comment) (ReactionList, int64, error) {
 	return findReactions(db.GetEngine(db.DefaultContext), FindReactionsOptions{
 		IssueID:   comment.IssueID,
 		CommentID: comment.ID,
@@ -79,7 +79,7 @@ func FindCommentReactions(comment *Comment) (ReactionList, error) {
 }
 
 // FindIssueReactions returns a ReactionList of all reactions from an issue
-func FindIssueReactions(issue *Issue, listOptions db.ListOptions) (ReactionList, error) {
+func FindIssueReactions(issue *Issue, listOptions db.ListOptions) (ReactionList, int64, error) {
 	return findReactions(db.GetEngine(db.DefaultContext), FindReactionsOptions{
 		ListOptions: listOptions,
 		IssueID:     issue.ID,
@@ -87,20 +87,22 @@ func FindIssueReactions(issue *Issue, listOptions db.ListOptions) (ReactionList,
 	})
 }
 
-func findReactions(e db.Engine, opts FindReactionsOptions) ([]*Reaction, error) {
-	e = e.
+func findReactions(e db.Engine, opts FindReactionsOptions) ([]*Reaction, int64, error) {
+	sess := e.
 		Where(opts.toConds()).
 		In("reaction.`type`", setting.UI.Reactions).
 		Asc("reaction.issue_id", "reaction.comment_id", "reaction.created_unix", "reaction.id")
 	if opts.Page != 0 {
-		e = db.SetEnginePagination(e, &opts)
+		sess = db.SetSessionPagination(sess, &opts)
 
 		reactions := make([]*Reaction, 0, opts.PageSize)
-		return reactions, e.Find(&reactions)
+		count, err := sess.FindAndCount(&reactions)
+		return reactions, count, err
 	}
 
 	reactions := make([]*Reaction, 0, 10)
-	return reactions, e.Find(&reactions)
+	count, err := sess.FindAndCount(&reactions)
+	return reactions, count, err
 }
 
 func createReaction(e db.Engine, opts *ReactionOptions) (*Reaction, error) {
@@ -120,7 +122,7 @@ func createReaction(e db.Engine, opts *ReactionOptions) (*Reaction, error) {
 		findOpts.CommentID = opts.Comment.ID
 	}
 
-	existingR, err := findReactions(e, findOpts)
+	existingR, _, err := findReactions(e, findOpts)
 	if err != nil {
 		return nil, err
 	}