fix: dedup should not remove ruby

Author: seuros

lockfile/normalize.go

@@ -7,20 +7,16 @@ import (
 	"strings"
 )
 
-var (
-	darwinPlatformVersionRegex = regexp.MustCompile(`^(.*-darwin)(\d+)$`)
-)
+var darwinPlatformVersionRegex = regexp.MustCompile(`^(.*-darwin)(\d+)$`)
 
 func normalizePlatformForLockfileOutput(platform string) string {
 	normalized := strings.ToLower(strings.TrimSpace(platform))
 	if normalized == "" {
 		return ""
 	}
-
 	if matches := darwinPlatformVersionRegex.FindStringSubmatch(normalized); matches != nil {
 		normalized = matches[1] + "-" + matches[2]
 	}
-
 	return normalized
 }
 

lockfile/writer.go

@@ -417,19 +417,22 @@ func (w *LockfileWriter) writePlatformsSection(lf *Lockfile, buf *bufio.Writer)
 		return nil
 	}
 
-	if _, err := buf.WriteString("\nPLATFORMS\n"); err != nil {
-		return err
-	}
-
-	// Deduplicate and sort platforms
+	// Deduplicate and sort platforms (excluding ruby, which Bundler omits).
 	platformSet := make(map[string]bool)
 	for _, p := range lf.Platforms {
 		normalized := normalizePlatformForLockfileOutput(p)
-		if normalized == "" {
+		if normalized == "" || normalized == "ruby" {
 			continue
 		}
 		platformSet[normalized] = true
 	}
+	if len(platformSet) == 0 {
+		return nil
+	}
+
+	if _, err := buf.WriteString("\nPLATFORMS\n"); err != nil {
+		return err
+	}
 
 	platforms := make([]string, 0, len(platformSet))
 	for p := range platformSet {

lockfile/writer_test.go

@@ -531,13 +531,6 @@ func TestIndentationAndFormatting(t *testing.T) {
 			t.Errorf("Line %d: gem dependency should have 6-space indent: %q", i+1, line)
 		}
 
-		// Platform entries should have 2-space indent
-		if strings.TrimSpace(line) == "ruby" && strings.HasPrefix(buf.String()[strings.Index(buf.String(), line)-20:], "PLATFORMS") {
-			if !strings.HasPrefix(line, "  ruby") {
-				t.Errorf("Line %d: platform should have 2-space indent: %q", i+1, line)
-			}
-		}
-
 		// Top-level dependencies should have 2-space indent
 		if strings.Contains(line, "rails (~> 8.1.0.rc1)") && !strings.HasPrefix(line, "  rails") {
 			t.Errorf("Line %d: dependency should have 2-space indent: %q", i+1, line)
@@ -572,8 +565,8 @@ func TestPlatformDeduplication(t *testing.T) {
 	rubyCount := strings.Count(output, "  ruby\n")
 	linuxCount := strings.Count(output, "  x86_64-linux\n")
 
-	if rubyCount != 1 {
-		t.Errorf("Expected 'ruby' platform to appear once, found %d times", rubyCount)
+	if rubyCount != 0 {
+		t.Errorf("Expected 'ruby' platform to be omitted, found %d times", rubyCount)
 	}
 	if linuxCount != 1 {
 		t.Errorf("Expected 'x86_64-linux' platform to appear once, found %d times", linuxCount)