Fix netrc one-line parsing and enforce dummy login writes

internal/netrc/netrc_test.go

@@ -3,6 +3,7 @@ package netrc
 import (
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 )
 
@@ -55,6 +56,28 @@ func TestUpsertUpdateExisting(t *testing.T) {
 	}
 }
 
+func TestUpsertUpdateExistingOneLineEntry(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "netrc")
+
+	initial := "machine other.host login dummy password otherpass\nmachine cache.example.com login dummy password oldtoken\n"
+	if err := os.WriteFile(path, []byte(initial), 0600); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := Upsert(path, "cache.example.com", "newtoken"); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	pw, err := GetPassword(path, "cache.example.com")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if pw != "newtoken" {
+		t.Errorf("password = %q, want %q", pw, "newtoken")
+	}
+}
+
 func TestUpsertAppend(t *testing.T) {
 	dir := t.TempDir()
 	path := filepath.Join(dir, "netrc")
@@ -197,3 +220,29 @@ func TestFilePermissionsCorrected(t *testing.T) {
 		t.Errorf("file permissions = %o, want 0600", perm)
 	}
 }
+
+func TestWriteUsesOneLineFormatAndDummyLoginFallback(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "netrc")
+
+	// Existing one-line entry with missing login should be normalized.
+	if err := os.WriteFile(path, []byte("machine cache.example.com password oldtoken\n"), 0600); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := Upsert(path, "cache.example.com", "newtoken"); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	content, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read error: %v", err)
+	}
+	text := string(content)
+	if !strings.Contains(text, "machine cache.example.com login dummy password newtoken\n") {
+		t.Fatalf("unexpected netrc content: %q", text)
+	}
+	if strings.Contains(text, "\nlogin ") || strings.Contains(text, "\npassword ") {
+		t.Fatalf("netrc entry should be written on one line: %q", text)
+	}
+}