refactor(registry): return default cache TTL by value (#296)

Return the default TTL without allocating a pointer, while preserving
the existing Duration.String nil behavior at CLI call sites.

Refs #174

Assisted-by: Codex (GPT-5) <noreply@openai.com>

Author: danielgaskins

cmd/add.go

@@ -131,10 +131,11 @@ func NewAddCmd(baseCmd *internalcmd.BaseCmd, opt ...cmdopts.CmdOption) (*cobra.C
 		"Directory for caching registry manifests",
 	)
 
+	defaultCacheTTL := regopts.DefaultCacheTTL()
 	cobraCommand.Flags().StringVar(
 		&c.CacheTTL,
 		"cache-ttl",
-		regopts.DefaultCacheTTL().String(),
+		defaultCacheTTL.String(),
 		"Time-to-live for cached registry manifests (e.g. 1h, 30m, 24h)",
 	)
 

cmd/config/tools/list.go

@@ -100,10 +100,11 @@ func NewListCmd(baseCmd *internalcmd.BaseCmd, opt ...cmdopts.CmdOption) (*cobra.
 		"Directory for caching registry manifests",
 	)
 
+	defaultCacheTTL := options.DefaultCacheTTL()
 	cobraCmd.Flags().StringVar(
 		&c.cacheTTL,
 		"cache-ttl",
-		options.DefaultCacheTTL().String(),
+		defaultCacheTTL.String(),
 		"Time-to-live for cached registry manifests (e.g. 1h, 30m, 24h)",
 	)
 

cmd/config/tools/set.go

@@ -91,10 +91,11 @@ func NewSetCmd(baseCmd *cmd.BaseCmd, opt ...cmdopts.CmdOption) (*cobra.Command,
 		"Directory for caching registry manifests",
 	)
 
+	defaultCacheTTL := options.DefaultCacheTTL()
 	cobraCmd.Flags().StringVar(
 		&c.cacheTTL,
 		"cache-ttl",
-		options.DefaultCacheTTL().String(),
+		defaultCacheTTL.String(),
 		"Time-to-live for cached registry manifests (e.g. 1h, 30m, 24h)",
 	)
 

cmd/search.go

@@ -148,10 +148,11 @@ func NewSearchCmd(baseCmd *internalcmd.BaseCmd, opt ...cmdopts.CmdOption) (*cobr
 		"Directory for caching registry manifests",
 	)
 
+	defaultCacheTTL := options.DefaultCacheTTL()
 	cobraCommand.Flags().StringVar(
 		&c.CacheTTL,
 		"cache-ttl",
-		options.DefaultCacheTTL().String(),
+		defaultCacheTTL.String(),
 		"Time-to-live for cached registry manifests (e.g. 1h, 30m, 24h)",
 	)
 

internal/cache/cache_options.go

@@ -35,7 +35,7 @@ func NewOptions(opts ...Option) (Options, error) {
 	// Default options.
 	o := Options{
 		dir:          dir,
-		ttl:          time.Duration(*options.DefaultCacheTTL()),
+		ttl:          time.Duration(options.DefaultCacheTTL()),
 		enabled:      true,
 		refreshCache: false,
 	}

internal/registry/options/build_options.go

@@ -91,7 +91,6 @@ func DefaultCacheDir() (string, error) {
 }
 
 // DefaultCacheTTL returns the default cache time-to-live.
-func DefaultCacheTTL() *config.Duration {
-	d := config.Duration(24 * time.Hour)
-	return &d
+func DefaultCacheTTL() config.Duration {
+	return config.Duration(24 * time.Hour)
 }

internal/registry/options/build_options_test.go

@@ -0,0 +1,18 @@
+package options
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/mozilla-ai/mcpd/internal/config"
+)
+
+func TestDefaultCacheTTL(t *testing.T) {
+	t.Parallel()
+
+	ttl := DefaultCacheTTL()
+	require.Equal(t, config.Duration(24*time.Hour), ttl)
+	require.Equal(t, "24h", ttl.String())
+}