mr_discussion: Provide better discussion information

In edit mode 'lab mr discussion' provides very basic instructions about
comment lines being ignored.  This is useful but it is not enough
information on the discussion thread being created.

Add the status of the MR, the MR ID, and if specified, the commit ID, to
the discussion information in edit mode.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>

cmd/mr_discussion.go

@@ -49,6 +49,17 @@ var mrCreateDiscussionCmd = &cobra.Command{
 			log.Fatal(err)
 		}
 
+		mr, err := lab.MRGet(rn, int(mrNum))
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		state := map[string]string{
+			"opened": "OPEN",
+			"closed": "CLOSED",
+			"merged": "MERGED",
+		}[mr.State]
+
 		body := ""
 		if filename != "" {
 			content, err := ioutil.ReadFile(filename)
@@ -57,14 +68,14 @@ var mrCreateDiscussionCmd = &cobra.Command{
 			}
 			body = string(content)
 		} else if commit == "" {
-			body, err = mrDiscussionMsg(msgs, "\n")
+			body, err = mrDiscussionMsg(int(mrNum), state, commit, msgs, "\n")
 			if err != nil {
 				_, f, l, _ := runtime.Caller(0)
 				log.Fatal(f+":"+strconv.Itoa(l)+" ", err)
 			}
 		} else {
 			body = getCommitBody(rn, commit)
-			body, err = mrDiscussionMsg(nil, body)
+			body, err = mrDiscussionMsg(int(mrNum), state, commit, nil, body)
 			if err != nil {
 				_, f, l, _ := runtime.Caller(0)
 				log.Fatal(f+":"+strconv.Itoa(l)+" ", err)
@@ -87,26 +98,43 @@ var mrCreateDiscussionCmd = &cobra.Command{
 	},
 }
 
-func mrDiscussionMsg(msgs []string, body string) (string, error) {
+func mrDiscussionMsg(mrNum int, state string, commit string, msgs []string, body string) (string, error) {
 	if len(msgs) > 0 {
 		return strings.Join(msgs[0:], "\n\n"), nil
 	}
 
-	text, err := mrDiscussionText(body)
+	text, err := mrDiscussionText(mrNum, state, commit, body)
 	if err != nil {
 		return "", err
 	}
 	return git.EditFile("MR_DISCUSSION", text)
 }
 
-func mrDiscussionText(body string) (string, error) {
-	tmpl := heredoc.Doc(`
+func mrDiscussionGetTemplate(commit string) string {
+	if commit == "" {
+		return heredoc.Doc(`
 		{{.InitMsg}}
-		{{.CommentChar}} Write a message for this discussion. Commented lines are discarded.`)
+		{{.CommentChar}} This thread is being started on {{.State}} Merge Request {{.MRnum}}.
+		{{.CommentChar}} Comment lines beginning with '{{.CommentChar}}' are discarded.`)
+	}
+	return heredoc.Doc(`
+		{{.InitMsg}}
+		{{.CommentChar}} This thread is being started on {{.State}} Merge Request {{.MRnum}} commit {{.Commit}}.
+		{{.CommentChar}} Do not delete patch tracking lines that begin with '|'.
+		{{.CommentChar}} Comment lines beginning with '{{.CommentChar}}' are discarded.`)
+}
 
+func mrDiscussionText(mrNum int, state string, commit string, body string) (string, error) {
+	tmpl := mrDiscussionGetTemplate(commit)
 	initMsg := body
 	commentChar := git.CommentChar()
 
+	if commit != "" {
+		if len(commit) > 11 {
+			commit = commit[:12]
+		}
+	}
+
 	t, err := template.New("tmpl").Parse(tmpl)
 	if err != nil {
 		return "", err
@@ -115,9 +143,15 @@ func mrDiscussionText(body string) (string, error) {
 	msg := &struct {
 		InitMsg     string
 		CommentChar string
+		State       string
+		MRnum       int
+		Commit      string
 	}{
 		InitMsg:     initMsg,
 		CommentChar: commentChar,
+		State:       state,
+		MRnum:       mrNum,
+		Commit:      commit,
 	}
 
 	var b bytes.Buffer