Rewrite implementation of edit pull request message

commands/pull_request.go

@@ -126,30 +126,48 @@ func writePullRequestTitleAndBody(repo *github.Repo) (title, body string, err er
 }
 
 func writePullRequestChanges(repo *github.Repo, messageFile string) error {
-	message := `
+	commits, err := git.RefList(repo.Base, repo.Head)
+	if err != nil {
+		return err
+	}
+
+	var defaultMsg, commitSummary string
+	if len(commits) == 1 {
+		defaultMsg, err = git.Show(commits[0])
+		if err != nil {
+			return err
+		}
+		defaultMsg = fmt.Sprintf("%s\n", defaultMsg)
+	} else if len(commits) > 1 {
+		commitLogs, err := git.Log(repo.Base, repo.Head)
+		if err != nil {
+			return err
+		}
+
+		if len(commitLogs) > 0 {
+			startRegexp := regexp.MustCompilePOSIX("^")
+			endRegexp := regexp.MustCompilePOSIX(" +$")
+
+			commitLogs = strings.TrimSpace(commitLogs)
+			commitLogs = startRegexp.ReplaceAllString(commitLogs, "# ")
+			commitLogs = endRegexp.ReplaceAllString(commitLogs, "")
+			commitSummary = `
+#
+# Changes:
+#
+%s`
+			commitSummary = fmt.Sprintf(commitSummary, commitLogs)
+		}
+	}
+
+	message := `%s
 # Requesting a pull to %s from %s
 #
 # Write a message for this pull request. The first block
 # of the text is the title and the rest is description.%s
 `
-	startRegexp := regexp.MustCompilePOSIX("^")
-	endRegexp := regexp.MustCompilePOSIX(" +$")
 
-	commitLogs, _ := git.Log(repo.Base, repo.Head)
-	var changesMsg string
-	if len(commitLogs) > 0 {
-		commitLogs = strings.TrimSpace(commitLogs)
-		commitLogs = startRegexp.ReplaceAllString(commitLogs, "# ")
-		commitLogs = endRegexp.ReplaceAllString(commitLogs, "")
-		changesMsg = `
-#
-# Changes:
-#
-%s`
-		changesMsg = fmt.Sprintf(changesMsg, commitLogs)
-	}
-
-	message = fmt.Sprintf(message, repo.FullBase(), repo.FullHead(), changesMsg)
+	message = fmt.Sprintf(message, defaultMsg, repo.FullBase(), repo.FullHead(), commitSummary)
 
 	return ioutil.WriteFile(messageFile, []byte(message), 0644)
 }

git/git.go

@@ -78,6 +78,15 @@ func RefList(a, b string) ([]string, error) {
 	return output, nil
 }
 
+func Show(sha string) (string, error) {
+	output, err := execGitCmd("show", "-s", "--format=%w(78,0,0)%s%+b", sha)
+	if err != nil {
+		return "", errors.New("Can't show commit for %s" + sha)
+	}
+
+	return output[0], nil
+}
+
 func Log(sha1, sha2 string) (string, error) {
 	execCmd := cmd.New("git")
 	execCmd.WithArg("log").WithArg("--no-color")
@@ -121,7 +130,10 @@ func execGitCmd(input ...string) (outputs []string, err error) {
 
 	out, err := cmd.ExecOutput()
 	for _, line := range strings.Split(out, "\n") {
-		outputs = append(outputs, string(line))
+		line = strings.TrimSpace(line)
+		if line != "" {
+			outputs = append(outputs, string(line))
+		}
 	}
 
 	return outputs, err

git/git_test.go

@@ -44,3 +44,17 @@ func TestGitRef(t *testing.T) {
 	assert.Equal(t, nil, err)
 	assert.NotEqual(t, "", gitRef)
 }
+
+func TestGitRefList(t *testing.T) {
+	refList, err := RefList("e357a98a1a580b09d4f1d9bf613a6a51e131ef6e", "49e984e2fe86f68c386aeb133b390d39e4264ec1")
+	assert.Equal(t, nil, err)
+	assert.Equal(t, 1, len(refList))
+
+	assert.Equal(t, "49e984e2fe86f68c386aeb133b390d39e4264ec1", refList[0])
+}
+
+func TestGitShow(t *testing.T) {
+	output, err := Show("ce20e63ad00751bfed5d08072b11cf1b43af1995")
+	assert.Equal(t, nil, err)
+	assert.Equal(t, "Add Git.RefList", output)
+}