feat(release): guard empty notes and recommend next tag

internal/releaseprep/releaseprep.go

@@ -5,11 +5,18 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"strconv"
 	"strings"
 )
 
 var versionPattern = regexp.MustCompile(`const String = "[^"]+"`)
 
+type semver struct {
+	major int
+	minor int
+	patch int
+}
+
 func Prepare(rootDir, version, releaseDate string) error {
 	normalizedVersion := strings.TrimPrefix(strings.TrimSpace(version), "v")
 	if normalizedVersion == "" {
@@ -32,6 +39,37 @@ func Prepare(rootDir, version, releaseDate string) error {
 	return nil
 }
 
+func RecommendedTag(rootDir string) (string, error) {
+	currentVersion, err := readCurrentVersion(rootDir)
+	if err != nil {
+		return "", err
+	}
+
+	unreleasedBody, err := readUnreleasedBody(rootDir)
+	if err != nil {
+		return "", err
+	}
+
+	parsed, err := parseSemver(currentVersion)
+	if err != nil {
+		return "", err
+	}
+
+	switch {
+	case strings.Contains(unreleasedBody, "### Removed"):
+		parsed.major++
+		parsed.minor = 0
+		parsed.patch = 0
+	case strings.Contains(unreleasedBody, "### Added"):
+		parsed.minor++
+		parsed.patch = 0
+	default:
+		parsed.patch++
+	}
+
+	return fmt.Sprintf("v%d.%d.%d", parsed.major, parsed.minor, parsed.patch), nil
+}
+
 func updateVersionFile(rootDir, version string) error {
 	path := filepath.Join(rootDir, "internal", "homesick", "version", "version.go")
 	contents, err := os.ReadFile(path)
@@ -52,17 +90,70 @@ func updateVersionFile(rootDir, version string) error {
 }
 
 func updateChangelog(rootDir, version, releaseDate string) error {
+	unreleasedBody, text, afterHeader, nextSectionStart, err := readChangelogState(rootDir)
+	if err != nil {
+		return err
+	}
+
+	if strings.TrimSpace(unreleasedBody) == "" {
+		return fmt.Errorf("unreleased section is empty")
+	}
+
+	path := filepath.Join(rootDir, "changelog.md")
+	newSection := fmt.Sprintf("## [%s] - %s\n", version, releaseDate)
+	newSection += "\n" + unreleasedBody
+	if !strings.HasSuffix(newSection, "\n") {
+		newSection += "\n"
+	}
+
+	updated := text[:afterHeader] + "\n" + newSection + text[nextSectionStart:]
+	if err := os.WriteFile(path, []byte(updated), 0o644); err != nil {
+		return fmt.Errorf("write changelog: %w", err)
+	}
+
+	return nil
+}
+
+func readCurrentVersion(rootDir string) (string, error) {
+	path := filepath.Join(rootDir, "internal", "homesick", "version", "version.go")
+	contents, err := os.ReadFile(path)
+	if err != nil {
+		return "", fmt.Errorf("read version file: %w", err)
+	}
+
+	match := versionPattern.FindString(string(contents))
+	if match == "" {
+		return "", fmt.Errorf("version constant not found in %s", path)
+	}
+
+	return strings.TrimSuffix(strings.TrimPrefix(match, `const String = "`), `"`), nil
+}
+
+func readUnreleasedBody(rootDir string) (string, error) {
+	unreleasedBody, _, _, _, err := readChangelogState(rootDir)
+	if err != nil {
+		return "", err
+	}
+
+	if strings.TrimSpace(unreleasedBody) == "" {
+		return "", fmt.Errorf("unreleased section is empty")
+	}
+
+	return unreleasedBody, nil
+}
+
+func readChangelogState(rootDir string) (string, string, int, int, error) {
 	path := filepath.Join(rootDir, "changelog.md")
 	contents, err := os.ReadFile(path)
 	if err != nil {
-		return fmt.Errorf("read changelog: %w", err)
+		return "", "", 0, 0, fmt.Errorf("read changelog: %w", err)
 	}
 
 	text := string(contents)
 	unreleasedHeader := "## [Unreleased]\n"
 	start := strings.Index(text, unreleasedHeader)
 	if start == -1 {
-		return fmt.Errorf("unreleased section not found in changelog")
+		return "", "", 0, 0, fmt.Errorf("unreleased section not found in changelog")
 	}
 
 	afterHeader := start + len(unreleasedHeader)
@@ -73,18 +164,27 @@ func updateChangelog(rootDir, version, releaseDate string) error {
 	nextSectionStart := afterHeader + nextSectionRelative
 	unreleasedBody := strings.TrimLeft(text[afterHeader:nextSectionStart], "\n")
 
-	newSection := fmt.Sprintf("## [%s] - %s\n", version, releaseDate)
-	if strings.TrimSpace(unreleasedBody) != "" {
-		newSection += "\n" + unreleasedBody
-		if !strings.HasSuffix(newSection, "\n") {
-			newSection += "\n"
-		}
+	return unreleasedBody, text, afterHeader, nextSectionStart, nil
+}
+
+func parseSemver(version string) (semver, error) {
+	parts := strings.Split(strings.TrimSpace(version), ".")
+	if len(parts) != 3 {
+		return semver{}, fmt.Errorf("version %q is not semantic major.minor.patch", version)
 	}
 
-	updated := text[:afterHeader] + "\n" + newSection + text[nextSectionStart:]
-	if err := os.WriteFile(path, []byte(updated), 0o644); err != nil {
-		return fmt.Errorf("write changelog: %w", err)
+	major, err := strconv.Atoi(parts[0])
+	if err != nil {
+		return semver{}, fmt.Errorf("parse major version: %w", err)
+	}
+	minor, err := strconv.Atoi(parts[1])
+	if err != nil {
+		return semver{}, fmt.Errorf("parse minor version: %w", err)
+	}
+	patch, err := strconv.Atoi(parts[2])
+	if err != nil {
+		return semver{}, fmt.Errorf("parse patch version: %w", err)
 	}
 
-	return nil
-}
+	return semver{major: major, minor: minor, patch: patch}, nil
+}