feat: Save PR message if creation fails (#113)

Saves the pull request description (entered via editor) to a temporary file if creating the pull request fails. It will re-use the title/description if the user tries to re-create the PR (also just logs the file path to the console in case they want that).

The most common cause of this error (in my experience) is expired auth tokens and/or the base branch of a stack having been deleted on GitHub. (we should provide a better experience for the latter but that's outside the scope of this PR)

cmd/av/helpers.go

@@ -34,7 +34,7 @@ func getRepo() (*git.Repo, error) {
 }
 
 func getDB(repo *git.Repo) (meta.DB, error) {
-	dbPath := path.Join(repo.GitDir(), "av", "av.db")
+	dbPath := path.Join(repo.AvDir(), "av.db")
 	existingStat, _ := os.Stat(dbPath)
 	db, err := jsonfiledb.OpenPath(dbPath)
 	if err != nil {

cmd/av/stack_sync.go

@@ -337,7 +337,7 @@ const stackSyncStateFile = "stack-sync.state.json"
 
 func readStackSyncState(repo *git.Repo) (stackSyncState, error) {
 	var state stackSyncState
-	data, err := os.ReadFile(path.Join(repo.GitDir(), "av", stackSyncStateFile))
+	data, err := os.ReadFile(path.Join(repo.AvDir(), stackSyncStateFile))
 	if err != nil {
 		return state, err
 	}
@@ -348,7 +348,7 @@ func readStackSyncState(repo *git.Repo) (stackSyncState, error) {
 }
 
 func writeStackSyncState(repo *git.Repo, state *stackSyncState) error {
-	avDir := path.Join(repo.GitDir(), "av")
+	avDir := repo.AvDir()
 	if _, err := os.Stat(avDir); err != nil {
 		if !os.IsNotExist(err) {
 			return err

internal/actions/pr.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/aviator-co/av/internal/utils/sanitize"
 	"os"
 	"path/filepath"
 	"strings"
@@ -234,8 +235,25 @@ func CreatePullRequest(
 			commits = append(commits, *commit)
 		}
 
-		// We need to open an editor to ask the user. Try to populate with
-		// reasonable defaults here.
+		// If a saved pull request description exists, use that.
+		saveFile := filepath.Join(repo.AvTmpDir(), fmt.Sprintf("av-pr-%s.md", sanitize.FileName(opts.BranchName)))
+		if _, err := os.Stat(saveFile); err == nil {
+			contents, err := os.ReadFile(saveFile)
+			if err != nil {
+				logrus.WithError(err).Warn("failed to read saved pull request description")
+			} else {
+				title, body := stringutils.ParseSubjectBody(string(contents))
+				if opts.Title == "" {
+					opts.Title = title
+				}
+				if opts.Body == "" {
+					opts.Body = body
+				}
+			}
+		}
+
+		// Try to populate the editor text using contextual information from the
+		// repository and commits included in this pull request.
 		if opts.Title == "" {
 			opts.Title = commits[0].Subject
 		}
@@ -255,6 +273,7 @@ func CreatePullRequest(
 			Body:    opts.Body,
 			Commits: commits,
 		})
+
 		res, err := editor.Launch(repo, editor.Config{
 			Text:           editorText,
 			TmpFilePattern: "pr-*.md",
@@ -267,6 +286,26 @@ func CreatePullRequest(
 		if opts.Title == "" {
 			return nil, errors.New("aborting pull request due to empty message")
 		}
+
+		defer func() {
+			// If we created the PR successfully, just make sure to clean up any
+			// lingering files.
+			if reterr == nil {
+				_ = os.Remove(saveFile)
+				return
+			}
+
+			// Otherwise, save what the user entered to a file so that it's not
+			// lost forever (and we can re-use it if they try again).
+			if err := os.WriteFile(saveFile, []byte(res), 0644); err != nil {
+				logrus.WithError(err).Error("failed to write pull request description to temporary file")
+				return
+			}
+			_, _ = fmt.Fprint(os.Stderr,
+				"  - saved pull request description to ", colors.UserInput(saveFile),
+				" (it will be automatically re-used if you try again)\n",
+			)
+		}()
 	}
 
 	prMeta, err := getPRMetadata(tx, branchMeta, &parentMeta)
@@ -284,6 +323,9 @@ func CreatePullRequest(
 		existingPR:  existingPR,
 	})
 	if err != nil {
+		_, _ = fmt.Fprint(os.Stderr,
+			colors.Failure("  - failed to create pull request: "), err, "\n",
+		)
 		return nil, errors.WrapIf(err, "failed to create PR")
 	}
 
@@ -382,7 +424,7 @@ func ensurePR(ctx context.Context, client *gh.Client, repoMeta meta.Repository,
 			Body:          gh.Ptr(githubv4.String(newBody)),
 		})
 		if err != nil {
-			return nil, false, errors.WrapIf(err, "updating PR")
+			return nil, false, errors.WithStack(err)
 		}
 		return updatedPR, false, nil
 	}
@@ -395,7 +437,7 @@ func ensurePR(ctx context.Context, client *gh.Client, repoMeta meta.Repository,
 		Draft:        gh.Ptr(githubv4.Boolean(opts.draft)),
 	})
 	if err != nil {
-		return nil, false, errors.WrapIf(err, "opening pull request")
+		return nil, false, errors.WithStack(err)
 	}
 	return pull, true, nil
 }

internal/git/git.go

@@ -38,6 +38,18 @@ func (r *Repo) GitDir() string {
 	return path.Join(r.repoDir, ".git")
 }
 
+func (r *Repo) AvDir() string {
+	return path.Join(r.GitDir(), "av")
+}
+
+func (r *Repo) AvTmpDir() string {
+	dir := path.Join(r.AvDir(), "tmp")
+	// Try to create the directory, but swallow the error since it will
+	// ultimately be surfaced when trying to create a file in the directory.
+	_ = os.MkdirAll(dir, 0755)
+	return dir
+}
+
 func (r *Repo) DefaultBranch() (string, error) {
 	ref, err := r.Git("symbolic-ref", "refs/remotes/origin/HEAD")
 	if err != nil {

internal/meta/jsonfiledb/db.go

@@ -16,7 +16,7 @@ type DB struct {
 }
 
 func RepoPath(repo *git.Repo) string {
-	return path.Join(repo.GitDir(), "av", "av.db")
+	return path.Join(repo.AvDir(), "av.db")
 }
 
 func OpenRepo(repo *git.Repo) (*DB, error) {

internal/utils/sanitize/filename.go

@@ -0,0 +1,24 @@
+package sanitize
+
+import (
+	"regexp"
+	"strings"
+)
+
+const (
+	fileNameMax = 100
+)
+
+var (
+	filenameReplacePattern = regexp.MustCompile(`[^a-zA-Z0-9]+`)
+)
+
+func FileName(name string) string {
+	name = strings.ToLower(name)
+	name = filenameReplacePattern.ReplaceAllString(name, "-")
+	if len(name) > fileNameMax {
+		name = name[:fileNameMax]
+	}
+	name = strings.Trim(name, "-")
+	return name
+}

internal/utils/sanitize/filename_test.go

@@ -0,0 +1,25 @@
+package sanitize
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestFileName(t *testing.T) {
+	for _, tt := range []struct{ Input, Output string }{
+		{"", ""},
+		{"  hello    world ", "hello-world"},
+		{"hello world", "hello-world"},
+		{"hello-world", "hello-world"},
+		{"hello_world", "hello-world"},
+		{"hello-world-123", "hello-world-123"},
+		{"hello-/-world-123!!!", "hello-world-123"},
+	} {
+		name := fmt.Sprintf("%q=>%q", tt.Input, tt.Output)
+		t.Run(name, func(t *testing.T) {
+			if got := FileName(tt.Input); got != tt.Output {
+				t.Errorf("FileName() = %q, want %q", got, tt.Output)
+			}
+		})
+	}
+}