Attach a refs/notes/byre note to each squash merge and push it

internal/git/git.go

@@ -3,6 +3,7 @@ package git
 import (
 	"errors"
 	"fmt"
+	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -217,8 +218,8 @@ const Remote = "origin"
 
 var ErrRemoteMoved = errors.New("the remote's branch has moved")
 
-func Push(repo, commit, branch string) error {
-	out, stderr, code, err := runCode(repo, nil, "push", "--porcelain", Remote, commit+":refs/heads/"+branch)
+func Push(repo, commit, branch, notes string) error {
+	out, stderr, code, err := runCode(repo, nil, "push", "--atomic", "--porcelain", Remote, commit+":refs/heads/"+branch, notes+":"+NotesRef)
 	if err != nil {
 		return err
 	}
@@ -239,7 +240,7 @@ func FastForward(repo, rev string) error {
 }
 
 func FetchFastForward(repo, branch string) error {
-	_, err := run(repo, "fetch", Remote, branch)
+	_, err := run(repo, "fetch", Remote)
 	if err != nil {
 		return err
 	}
@@ -303,10 +304,26 @@ func runEnv(dir string, env []string, args ...string) (string, error) {
 	return out, nil
 }
 
+func runInput(dir string, env []string, input string, args ...string) (string, error) {
+	out, stderr, code, err := runCodeInput(dir, env, strings.NewReader(input), args...)
+	if err != nil {
+		return "", err
+	}
+	if code != 0 {
+		return "", fmt.Errorf("git %s: exit status %d: %s", strings.Join(args, " "), code, stderr)
+	}
+	return out, nil
+}
+
 func runCode(dir string, env []string, args ...string) (string, string, int, error) {
+	return runCodeInput(dir, env, nil, args...)
+}
+
+func runCodeInput(dir string, env []string, stdin io.Reader, args ...string) (string, string, int, error) {
 	cmd := exec.Command("git", args...)
 	cmd.Dir = dir
 	cmd.Env = append(os.Environ(), env...)
+	cmd.Stdin = stdin
 	stderr := &strings.Builder{}
 	cmd.Stderr = stderr
 	out, err := cmd.Output()