[fp-enhancer] Functional Programming & Immutability Enhancements

pkg/cli/run_workflow_execution.go

@@ -149,17 +149,15 @@ func RunWorkflowOnGitHub(ctx context.Context, workflowIdOrName string, enable bo
 		}
 	}
 
-	// Determine the lock file name based on the workflow source
-	var lockFileName string
-	var lockFilePath string
-
 	// Normalize workflow ID to handle both \"workflow-name\" and \".github/workflows/workflow-name.md\" formats
 	normalizedID := normalizeWorkflowID(workflowIdOrName)
 
-	if repoOverride != "" {
-		// For remote repositories, construct lock file name from normalized ID
-		lockFileName = normalizedID + ".lock.yml"
-	} else {
+	// Construct lock file name from normalized ID (same for both local and remote)
+	lockFileName := normalizedID + ".lock.yml"
+
+	// For local workflows, validate the workflow exists and check for lock file
+	var lockFilePath string
+	if repoOverride == "" {
 		// For local workflows, validate the workflow exists locally
 		workflowsDir := getWorkflowsDir()
 
@@ -168,9 +166,6 @@ func RunWorkflowOnGitHub(ctx context.Context, workflowIdOrName string, enable bo
 			return fmt.Errorf("failed to find workflow in local .github/workflows: %w", err)
 		}
 
-		// For local workflows, construct lock file name from normalized ID
-		lockFileName = normalizedID + ".lock.yml"
-
 		// Check if the lock file exists in .github/workflows
 		lockFilePath = filepath.Join(".github/workflows", lockFileName)
 		if _, err := os.Stat(lockFilePath); os.IsNotExist(err) {

pkg/cli/workflows.go

@@ -13,6 +13,7 @@ import (
 	"github.com/githubnext/gh-aw/pkg/constants"
 	"github.com/githubnext/gh-aw/pkg/logger"
 	"github.com/githubnext/gh-aw/pkg/parser"
+	"github.com/githubnext/gh-aw/pkg/sliceutil"
 	"github.com/githubnext/gh-aw/pkg/workflow"
 )
 
@@ -207,13 +208,9 @@ func getAvailableWorkflowNames() []string {
 		return nil
 	}
 
-	var names []string
-	for _, file := range mdFiles {
-		base := filepath.Base(file)
-		name := strings.TrimSuffix(base, ".md")
-		names = append(names, name)
-	}
-	return names
+	return sliceutil.Map(mdFiles, func(file string) string {
+		return strings.TrimSuffix(filepath.Base(file), ".md")
+	})
 }
 
 // suggestWorkflowNames returns up to 3 similar workflow names using fuzzy matching
@@ -240,11 +237,5 @@ func isWorkflowFile(filename string) bool {
 
 // filterWorkflowFiles filters out non-workflow files from a list of markdown files.
 func filterWorkflowFiles(files []string) []string {
-	var filtered []string
-	for _, file := range files {
-		if isWorkflowFile(file) {
-			filtered = append(filtered, file)
-		}
-	}
-	return filtered
+	return sliceutil.Filter(files, isWorkflowFile)
 }

pkg/sliceutil/sliceutil.go

@@ -60,3 +60,44 @@ func MapToSlice[K comparable, V any](m map[K]V) []K {
 	}
 	return result
 }
+
+// FilterMap filters and transforms elements in a single pass.
+// Only elements where the predicate returns true are transformed and included in the result.
+// This is a pure function that does not modify the input slice.
+func FilterMap[T, U any](slice []T, predicate func(T) bool, transform func(T) U) []U {
+	result := make([]U, 0, len(slice))
+	for _, item := range slice {
+		if predicate(item) {
+			result = append(result, transform(item))
+		}
+	}
+	return result
+}
+
+// FilterMapKeys returns map keys that match the given predicate.
+// The order of elements is not guaranteed as map iteration order is undefined.
+// This is a pure function that does not modify the input map.
+func FilterMapKeys[K comparable, V any](m map[K]V, predicate func(K, V) bool) []K {
+	result := make([]K, 0, len(m))
+	for key, value := range m {
+		if predicate(key, value) {
+			result = append(result, key)
+		}
+	}
+	return result
+}
+
+// Deduplicate returns a new slice with duplicate elements removed.
+// The order of first occurrence is preserved.
+// This is a pure function that does not modify the input slice.
+func Deduplicate[T comparable](slice []T) []T {
+	seen := make(map[T]bool, len(slice))
+	result := make([]T, 0, len(slice))
+	for _, item := range slice {
+		if !seen[item] {
+			seen[item] = true
+			result = append(result, item)
+		}
+	}
+	return result
+}

pkg/workflow/compiler_jobs.go

@@ -12,6 +12,7 @@ import (
 	"github.com/githubnext/gh-aw/pkg/constants"
 	"github.com/githubnext/gh-aw/pkg/logger"
 	"github.com/githubnext/gh-aw/pkg/parser"
+	"github.com/githubnext/gh-aw/pkg/sliceutil"
 	"github.com/goccy/go-yaml"
 )
 
@@ -92,15 +93,12 @@ func jobDependsOnAgent(jobConfig map[string]any) bool {
 // getCustomJobsDependingOnPreActivation returns custom job names that explicitly depend on pre_activation.
 // These jobs run after pre_activation but before activation, and activation should depend on them.
 func (c *Compiler) getCustomJobsDependingOnPreActivation(customJobs map[string]any) []string {
-	var jobNames []string
-	for jobName, jobConfig := range customJobs {
+	return sliceutil.FilterMapKeys(customJobs, func(jobName string, jobConfig any) bool {
 		if configMap, ok := jobConfig.(map[string]any); ok {
-			if jobDependsOnPreActivation(configMap) {
-				jobNames = append(jobNames, jobName)
-			}
+			return jobDependsOnPreActivation(configMap)
 		}
-	}
-	return jobNames
+		return false
+	})
 }
 
 // getReferencedCustomJobs returns custom job names that are referenced in the given content.
@@ -109,17 +107,13 @@ func (c *Compiler) getReferencedCustomJobs(content string, customJobs map[string
 	if content == "" || customJobs == nil {
 		return nil
 	}
-	var referencedJobs []string
-	for jobName := range customJobs {
-		// Check for patterns like "needs.job_name." which covers:
-		// - needs.job_name.outputs.X
-		// - ${{ needs.job_name.outputs.X }}
-		// - needs.job_name.result
-		if strings.Contains(content, fmt.Sprintf("needs.%s.", jobName)) {
-			referencedJobs = append(referencedJobs, jobName)
-		}
-	}
-	return referencedJobs
+	// Check for patterns like "needs.job_name." which covers:
+	// - needs.job_name.outputs.X
+	// - ${{ needs.job_name.outputs.X }}
+	// - needs.job_name.result
+	return sliceutil.FilterMapKeys(customJobs, func(jobName string, _ any) bool {
+		return strings.Contains(content, fmt.Sprintf("needs.%s.", jobName))
+	})
 }
 
 // buildJobs creates all jobs for the workflow and adds them to the job manager

pkg/workflow/compiler_safe_outputs_config.go

@@ -17,7 +17,7 @@ type handlerConfigBuilder struct {
 // newHandlerConfigBuilder creates a new handler config builder
 func newHandlerConfigBuilder() *handlerConfigBuilder {
 	return &handlerConfigBuilder{
-		config: make(map[string]any),
+		config: map[string]any{},
 	}
 }