fix(loader): replace panic with error handling in template loader

Replace panic with proper error return when dialers are missing,
allowing callers to handle the situation gracefully.

Changes:
- Modify LoadTemplatesWithTags to return ([]*templates.Template, error)
- Modify LoadTemplates to return ([]*templates.Template, error)
- Modify Load to return error
- Replace panic("dialers with executionId...") with fmt.Errorf
- Replace panic("could not create wait group") with fmt.Errorf
- Update all callers to handle the new error return

Callers updated:
- internal/runner/lazy.go
- internal/runner/runner.go
- internal/server/nuclei_sdk.go
- lib/multi.go
- lib/sdk.go
- cmd/integration-test/library.go
- pkg/protocols/common/automaticscan/util.go
- pkg/catalog/loader/loader_bench_test.go

Fixes #6674

cmd/integration-test/library.go

@@ -132,7 +132,9 @@ func executeNucleiAsLibrary(templatePath, templateURL string) ([]string, error)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not create loader")
 	}
-	store.Load()
+	if err := store.Load(); err != nil {
+		return nil, errors.Wrap(err, "could not load templates")
+	}
 
 	_ = engine.Execute(context.Background(), store.Templates(), provider.NewSimpleInputProviderWithUrls(defaultOpts.ExecutionId, templateURL))
 	engine.WorkPool().Wait() // Wait for the scan to finish

internal/runner/lazy.go

@@ -67,7 +67,10 @@ func GetAuthTmplStore(opts *types.Options, catalog catalog.Catalog, execOpts *pr
 // GetLazyAuthFetchCallback returns a lazy fetch callback for auth secrets
 func GetLazyAuthFetchCallback(opts *AuthLazyFetchOptions) authx.LazyFetchSecret {
 	return func(d *authx.Dynamic) error {
-		tmpls := opts.TemplateStore.LoadTemplates([]string{d.TemplatePath})
+		tmpls, err := opts.TemplateStore.LoadTemplates([]string{d.TemplatePath})
+		if err != nil {
+			return fmt.Errorf("failed to load templates: %w", err)
+		}
 		if len(tmpls) == 0 {
 			return fmt.Errorf("%w for path: %s", disk.ErrNoTemplatesFound, d.TemplatePath)
 		}
@@ -140,9 +143,9 @@ func GetLazyAuthFetchCallback(opts *AuthLazyFetchOptions) authx.LazyFetchSecret
 			// log result of template in result file/screen
 			_ = writer.WriteResult(e, opts.ExecOpts.Output, opts.ExecOpts.Progress, opts.ExecOpts.IssuesClient)
 		}
-		_, err := tmpl.Executer.ExecuteWithResults(ctx)
-		if err != nil {
-			finalErr = err
+		_, execErr := tmpl.Executer.ExecuteWithResults(ctx)
+		if execErr != nil {
+			finalErr = execErr
 		}
 		// store extracted result in auth context
 		d.Extracted = data

internal/runner/runner.go

@@ -660,7 +660,9 @@ func (r *Runner) RunEnumeration() error {
 		}
 		return nil // exit
 	}
-	store.Load()
+	if err := store.Load(); err != nil {
+		return err
+	}
 	// TODO: remove below functions after v3 or update warning messages
 	templates.PrintDeprecatedProtocolNameMsgIfApplicable(r.options.Silent, r.options.Verbose)
 

internal/server/nuclei_sdk.go

@@ -125,7 +125,9 @@ func newNucleiExecutor(opts *NucleiExecutorOptions) (*nucleiExecutor, error) {
 	if err != nil {
 		return nil, errors.Wrap(err, "Could not create loader options.")
 	}
-	store.Load()
+	if err := store.Load(); err != nil {
+		return nil, errors.Wrap(err, "Could not load templates.")
+	}
 
 	return &nucleiExecutor{
 		engine:       executorEngine,

lib/multi.go

@@ -150,7 +150,9 @@ func (e *ThreadSafeNucleiEngine) ExecuteNucleiWithOptsCtx(ctx context.Context, t
 	if err != nil {
 		return errkit.Wrapf(err, "Could not create loader client: %s", err)
 	}
-	store.Load()
+	if err := store.Load(); err != nil {
+		return errkit.Wrapf(err, "Could not load templates: %s", err)
+	}
 
 	inputProvider := provider.NewSimpleInputProviderWithUrls(e.eng.opts.ExecutionId, targets...)
 

lib/sdk.go

@@ -110,7 +110,9 @@ func (e *NucleiEngine) LoadAllTemplates() error {
 	if err != nil {
 		return errkit.Wrapf(err, "Could not create loader client: %s", err)
 	}
-	e.store.Load()
+	if err := e.store.Load(); err != nil {
+		return errkit.Wrapf(err, "Could not load templates: %s", err)
+	}
 	e.templatesLoaded = true
 	return nil
 }

pkg/catalog/loader/loader.go

@@ -333,9 +333,14 @@ func (store *Store) RegisterPreprocessor(preprocessor templates.Preprocessor) {
 
 // Load loads all the templates from a store, performs filtering and returns
 // the complete compiled templates for a nuclei execution configuration.
-func (store *Store) Load() {
-	store.templates = store.LoadTemplates(store.finalTemplates)
+func (store *Store) Load() error {
+	templates, err := store.LoadTemplates(store.finalTemplates)
+	if err != nil {
+		return err
+	}
+	store.templates = templates
 	store.workflows = store.LoadWorkflows(store.finalWorkflows)
+	return nil
 }
 
 var templateIDPathMap map[string]string
@@ -637,7 +642,7 @@ func isParsingError(store *Store, message string, template string, err error) bo
 }
 
 // LoadTemplates takes a list of templates and returns paths for them
-func (store *Store) LoadTemplates(templatesList []string) []*templates.Template {
+func (store *Store) LoadTemplates(templatesList []string) ([]*templates.Template, error) {
 	return store.LoadTemplatesWithTags(templatesList, nil)
 }
 
@@ -668,7 +673,8 @@ func (store *Store) LoadWorkflows(workflowsList []string) []*templates.Template
 
 // LoadTemplatesWithTags takes a list of templates and extra tags
 // returning templates that match.
-func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templates.Template {
+// Returns an error if dialers are not initialized for the given execution ID.
+func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) ([]*templates.Template, error) {
 	defer store.saveMetadataIndexOnce()
 
 	indexFilter := store.indexFilter
@@ -708,7 +714,7 @@ func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templ
 
 	wgLoadTemplates, errWg := syncutil.New(syncutil.WithSize(concurrency))
 	if errWg != nil {
-		panic("could not create wait group")
+		return nil, fmt.Errorf("could not create wait group: %w", errWg)
 	}
 
 	if typesOpts.ExecutionId == "" {
@@ -717,7 +723,7 @@ func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templ
 
 	dialers := protocolstate.GetDialersWithId(typesOpts.ExecutionId)
 	if dialers == nil {
-		panic("dialers with executionId " + typesOpts.ExecutionId + " not found")
+		return nil, fmt.Errorf("dialers with executionId %s not found", typesOpts.ExecutionId)
 	}
 
 	for _, templatePath := range includedTemplates {
@@ -852,7 +858,7 @@ func (store *Store) LoadTemplatesWithTags(templatesList, tags []string) []*templ
 		return loadedTemplates.Slice[i].Path < loadedTemplates.Slice[j].Path
 	})
 
-	return loadedTemplates.Slice
+	return loadedTemplates.Slice, nil
 }
 
 // IsHTTPBasedProtocolUsed returns true if http/headless protocol is being used for

pkg/catalog/loader/loader_bench_test.go

@@ -71,7 +71,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 
@@ -89,7 +89,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 
@@ -107,7 +107,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 
@@ -125,7 +125,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 
@@ -143,7 +143,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 
@@ -161,7 +161,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 
@@ -181,7 +181,7 @@ func BenchmarkLoadTemplates(b *testing.B) {
 		b.ReportAllocs()
 
 		for b.Loop() {
-			_ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
+			_, _ = store.LoadTemplates([]string{config.DefaultConfig.TemplatesDirectory})
 		}
 	})
 }

pkg/protocols/common/automaticscan/util.go

@@ -37,7 +37,10 @@ func getTemplateDirs(opts Options) ([]string, error) {
 
 // LoadTemplatesWithTags loads and returns templates with given tags
 func LoadTemplatesWithTags(opts Options, templateDirs []string, tags []string, logInfo bool) ([]*templates.Template, error) {
-	finalTemplates := opts.Store.LoadTemplatesWithTags(templateDirs, tags)
+	finalTemplates, err := opts.Store.LoadTemplatesWithTags(templateDirs, tags)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not load templates")
+	}
 	if len(finalTemplates) == 0 {
 		return nil, errors.New("could not find any templates with tech tag")
 	}