fix(pr): refuse pr comment and pr attachment on issues

Gitea serves pull request comments and attachments through issue
endpoints, so tea pr comment create 1 posted on issue #1. pr comment and
pr attachment commands now check that the number is a pull request, and
comment IDs that the comment is on one, and point at the issue command
otherwise: "#1 in alice/project is an issue, not a pull request; use tea
issue comment create 1". Issues gain a kind field (issue or pull) in JSON.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/comments.go

@@ -19,7 +19,25 @@ func commentRecord(item services.Comment) terminal.Record {
 	return terminal.Record{Heading: terminal.Row(strconv.FormatInt(item.ID, 10), item.Author), Lines: []string{item.Body, item.URL}}
 }
 
-func (a *application) commentCommand() *cobra.Command {
+// requirePull fails unless issue n is a pull request, for pr commands that Gitea serves through
+// issue endpoints and would otherwise apply to the issue with that number.
+func requirePull(cmd *cobra.Command, t target, n int64) error {
+	item, err := (services.Issues{Client: t.client, Repository: t.Repo}).View(cmd.Context(), n)
+	if err != nil {
+		return err
+	}
+	if item.Kind != services.KindPull {
+		return fmt.Errorf("#%d in %s is an issue, not a pull request; use %s %d", n, t.Repo, issueCommandPath(cmd), n)
+	}
+	return nil
+}
+
+// issueCommandPath names the issue command that matches a pr command, such as "tea issue comment".
+func issueCommandPath(cmd *cobra.Command) string {
+	return strings.Replace(cmd.CommandPath(), " pr ", " issue ", 1)
+}
+
+func (a *application) commentCommand(kind refKind) *cobra.Command {
 	group := &cobra.Command{Use: "comment", Short: "Manage discussion comments"}
 	var limit, page int
 	list := &cobra.Command{Use: "list <number>", Short: "List comments on an issue or pull request", Args: argsExact(1), RunE: func(cmd *cobra.Command, args []string) error {
@@ -31,6 +49,11 @@ func (a *application) commentCommand() *cobra.Command {
 		if err != nil {
 			return err
 		}
+		if kind == pullRef {
+			if err := requirePull(cmd, target, n); err != nil {
+				return err
+			}
+		}
 		items, err := (services.Comments{Client: target.client, Repository: target.Repo}).Page(cmd.Context(), n, limit, page)
 		if err != nil {
 			return err
@@ -77,6 +100,20 @@ func (a *application) commentCommand() *cobra.Command {
 				return err
 			}
 			service := services.Comments{Client: target.client, Repository: target.Repo}
+			if kind == pullRef && verb == "create" {
+				if err := requirePull(cmd, target, id); err != nil {
+					return err
+				}
+			}
+			if kind == pullRef && verb != "create" {
+				current, err := service.View(cmd.Context(), id)
+				if err != nil {
+					return err
+				}
+				if !current.Pull {
+					return fmt.Errorf("comment %d in %s is on an issue, not a pull request; use %s %d", id, target.Repo, issueCommandPath(cmd), id)
+				}
+			}
 			if verb == "create" || verb == "edit" {
 				if useEditor {
 					initial := ""