fix(logging): eliminate global slog usage per original PR intent

- Add NewLogIgnorePluginLoadErrorFilterFunc(logger) factory so plugin load
  warnings are routed through the DI logger instead of global slog
- Add FindPluginsWithErrorFilter to thread logger through CLI plugin loading
- Update loadCLIPlugins, plugin_list, plugin_uninstall, plugin_update to use
  DI logger for plugin load warnings
- Add WithLogger option to getter for HTTP fetch debug logging
- Remove slog.SetDefault() from newRootCmdWithConfig; global slog is no longer
  mutated by the CLI
- Replace slog.Default() fallbacks with slog.New(slog.DiscardHandler) in
  public API functions whose signatures cannot change until Helm v5
  (ProcessDependencies, ValidateAgainstSchema, ValidateAgainstSingleSchema,
  IndexFile.log)

Signed-off-by: JaeguKim <rlaworn1993@gmail.com>

internal/chart/v3/util/dependencies.go

@@ -30,7 +30,7 @@ import (
 
 // ProcessDependencies checks through this chart's dependencies, processing accordingly.
 func ProcessDependencies(c *chart.Chart, v common.Values) error {
-	logger := slog.Default()
+	logger := slog.New(slog.DiscardHandler)
 	if err := processDependencyEnabled(c, v, "", logger); err != nil {
 		return err
 	}

internal/plugin/loader.go

@@ -159,9 +159,19 @@ func LoadDir(dirname string) (Plugin, error) {
 	return pm.CreatePlugin(dirname, m)
 }
 
+// NewLogIgnorePluginLoadErrorFilterFunc returns an ErrorFilterFunc that logs
+// plugin load errors using the provided logger and ignores them.
+func NewLogIgnorePluginLoadErrorFilterFunc(logger *slog.Logger) ErrorFilterFunc {
+	return func(pluginYAML string, err error) error {
+		logger.Warn("failed to load plugin (ignoring)", slog.String("plugin_yaml", pluginYAML), slog.Any("error", err))
+		return nil
+	}
+}
+
+// LogIgnorePluginLoadErrorFilterFunc logs plugin load errors and ignores them.
+// Deprecated: Use NewLogIgnorePluginLoadErrorFilterFunc to inject a logger.
 func LogIgnorePluginLoadErrorFilterFunc(pluginYAML string, err error) error {
-	slog.Warn("failed to load plugin (ignoring)", slog.String("plugin_yaml", pluginYAML), slog.Any("error", err))
-	return nil
+	return NewLogIgnorePluginLoadErrorFilterFunc(slog.New(slog.DiscardHandler))(pluginYAML, err)
 }
 
 // errorFilterFunc is a function that can filter errors during plugin loading
@@ -205,13 +215,20 @@ type findFunc func(pluginsDir string) ([]Plugin, error)
 // filterFunc is a function that filters plugins
 type filterFunc func(Plugin) bool
 
-// FindPlugins returns a list of plugins that match the descriptor
-// Errors loading a plugin are ignored with a warning
-func FindPlugins(pluginsDirs []string, descriptor Descriptor) ([]Plugin, error) {
-	loadAllIgnoreErrors := func(pluginsDir string) ([]Plugin, error) {
-		return LoadAllDir(pluginsDir, LogIgnorePluginLoadErrorFilterFunc)
+// FindPluginsWithErrorFilter returns a list of plugins that match the descriptor,
+// using the provided error filter to handle individual plugin load errors.
+func FindPluginsWithErrorFilter(pluginsDirs []string, descriptor Descriptor, errFilter ErrorFilterFunc) ([]Plugin, error) {
+	loadAll := func(pluginsDir string) ([]Plugin, error) {
+		return LoadAllDir(pluginsDir, errFilter)
 	}
-	return findPlugins(pluginsDirs, loadAllIgnoreErrors, makeDescriptorFilter(descriptor))
+	return findPlugins(pluginsDirs, loadAll, makeDescriptorFilter(descriptor))
+}
+
+// FindPlugins returns a list of plugins that match the descriptor.
+// Errors loading a plugin are silently ignored.
+// Deprecated: Use FindPluginsWithErrorFilter to handle load errors explicitly.
+func FindPlugins(pluginsDirs []string, descriptor Descriptor) ([]Plugin, error) {
+	return FindPluginsWithErrorFilter(pluginsDirs, descriptor, LogIgnorePluginLoadErrorFilterFunc)
 }
 
 // findPlugins is the internal implementation that uses the find and filter functions

pkg/chart/common/util/jsonschema.go

@@ -74,7 +74,7 @@ func newHTTPURLLoader() *HTTPURLLoader {
 
 // ValidateAgainstSchema checks that values does not violate the structure laid out in schema
 func ValidateAgainstSchema(ch chart.Charter, values map[string]any) error {
-	logger := slog.Default()
+	logger := slog.New(slog.DiscardHandler)
 	chrt, err := chart.NewAccessor(ch)
 	if err != nil {
 		return err
@@ -123,7 +123,7 @@ func ValidateAgainstSchema(ch chart.Charter, values map[string]any) error {
 
 // ValidateAgainstSingleSchema checks that values does not violate the structure laid out in this schema
 func ValidateAgainstSingleSchema(values common.Values, schemaJSON []byte) (reterr error) {
-	logger := slog.Default()
+	logger := slog.New(slog.DiscardHandler)
 	defer func() {
 		if r := recover(); r != nil {
 			reterr = fmt.Errorf("unable to validate schema: %s", r)

pkg/chart/v2/util/dependencies.go

@@ -30,7 +30,7 @@ import (
 
 // ProcessDependencies checks through this chart's dependencies, processing accordingly.
 func ProcessDependencies(c *chart.Chart, v common.Values) error {
-	logger := slog.Default()
+	logger := slog.New(slog.DiscardHandler)
 	if err := processDependencyEnabled(c, v, "", logger); err != nil {
 		return err
 	}

pkg/cmd/load_plugins.go

@@ -62,7 +62,7 @@ func loadCLIPlugins(baseCmd *cobra.Command, out io.Writer, logger *slog.Logger)
 	descriptor := plugin.Descriptor{
 		Type: "cli/v1",
 	}
-	found, err := plugin.FindPlugins(dirs, descriptor)
+	found, err := plugin.FindPluginsWithErrorFilter(dirs, descriptor, plugin.NewLogIgnorePluginLoadErrorFilterFunc(logger))
 	if err != nil {
 		logger.Error("failed to load plugins", slog.String("error", err.Error()))
 		return

pkg/cmd/plugin_list.go

@@ -42,7 +42,7 @@ func newPluginListCmd(out io.Writer, logger *slog.Logger) *cobra.Command {
 			descriptor := plugin.Descriptor{
 				Type: pluginType,
 			}
-			plugins, err := plugin.FindPlugins(dirs, descriptor)
+			plugins, err := plugin.FindPluginsWithErrorFilter(dirs, descriptor, plugin.NewLogIgnorePluginLoadErrorFilterFunc(logger))
 			if err != nil {
 				return err
 			}

pkg/cmd/plugin_uninstall.go

@@ -63,7 +63,7 @@ func (o *pluginUninstallOptions) complete(args []string) error {
 
 func (o *pluginUninstallOptions) run(out io.Writer) error {
 	o.logger.Debug("loading installer plugins", "dir", settings.PluginsDirectory)
-	plugins, err := plugin.LoadAllDir(settings.PluginsDirectory, plugin.LogIgnorePluginLoadErrorFilterFunc)
+	plugins, err := plugin.LoadAllDir(settings.PluginsDirectory, plugin.NewLogIgnorePluginLoadErrorFilterFunc(o.logger))
 	if err != nil {
 		return err
 	}

pkg/cmd/plugin_update.go

@@ -63,7 +63,7 @@ func (o *pluginUpdateOptions) complete(args []string) error {
 
 func (o *pluginUpdateOptions) run(out io.Writer) error {
 	o.logger.Debug("loading installed plugins", "path", settings.PluginsDirectory)
-	plugins, err := plugin.LoadAllDir(settings.PluginsDirectory, plugin.LogIgnorePluginLoadErrorFilterFunc)
+	plugins, err := plugin.LoadAllDir(settings.PluginsDirectory, plugin.NewLogIgnorePluginLoadErrorFilterFunc(o.logger))
 	if err != nil {
 		return err
 	}

pkg/cmd/root.go

@@ -177,7 +177,6 @@ func newRootCmdWithConfig(actionConfig *action.Configuration, out io.Writer, arg
 	flags.Parse(args)
 
 	logger := logSetup(settings.Debug)
-	slog.SetDefault(logger)
 	actionConfig.SetLogger(logger.Handler())
 
 	// Validate color mode setting

pkg/cmd/root_test.go

@@ -149,9 +149,9 @@ func TestRootCmdLogger(t *testing.T) {
 		t.Error("expected actionConfig logger to be set, got discard handler")
 	}
 
-	// slog.SetDefault is called so the global default should use the same handler
-	if l.Handler() != slog.Default().Handler() {
-		t.Error("expected actionConfig logger to match the global slog default logger")
+	// slog.SetDefault is not called, so the global default should differ from the actionConfig logger
+	if l.Handler() == slog.Default().Handler() {
+		t.Error("expected actionConfig logger to differ from the global slog default logger")
 	}
 }
 

pkg/getter/getter.go

@@ -19,6 +19,7 @@ package getter
 import (
 	"bytes"
 	"fmt"
+	"log/slog"
 	"net/http"
 	"slices"
 	"time"
@@ -49,6 +50,7 @@ type getterOptions struct {
 	timeout               time.Duration
 	transport             *http.Transport
 	artifactType          string
+	logger                *slog.Logger
 }
 
 // Option allows specifying various settings configurable by the user for overriding the defaults
@@ -152,6 +154,13 @@ func WithArtifactType(artifactType string) Option {
 	}
 }
 
+// WithLogger sets the logger for the getter.
+func WithLogger(logger *slog.Logger) Option {
+	return func(opts *getterOptions) {
+		opts.logger = logger
+	}
+}
+
 // Getter is an interface to support GET to the specified URL.
 type Getter interface {
 	// Get file content by url string

pkg/getter/httpgetter.go

@@ -88,13 +88,17 @@ func (g *HTTPGetter) get(href string, opts getterOptions) (*bytes.Buffer, error)
 		return nil, err
 	}
 
-	slog.Debug("fetching", "url", href)
+	logger := opts.logger
+	if logger == nil {
+		logger = slog.New(slog.DiscardHandler)
+	}
+	logger.Debug("fetching", "url", href)
 	resp, err := client.Do(req)
 	if err != nil {
 		return nil, err
 	}
 	defer resp.Body.Close()
-	slog.Debug("fetch complete", "url", href, "status", resp.Status, "content-length", resp.ContentLength)
+	logger.Debug("fetch complete", "url", href, "status", resp.Status, "content-length", resp.ContentLength)
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("failed to fetch %s : %s", href, resp.Status)
 	}

pkg/repo/v1/index.go

@@ -99,7 +99,7 @@ func (i IndexFile) log() *slog.Logger {
 	if i.Logger != nil {
 		return i.Logger
 	}
-	return slog.Default()
+	return slog.New(slog.DiscardHandler)
 }
 
 // NewIndexFile initializes an index.