fix: support mixed hook formats in UnmarshalYAML

cli/azd/pkg/ext/hooks_config.go

@@ -3,34 +3,77 @@
 
 package ext
 
-import "fmt"
+import (
+	"fmt"
+
+	"gopkg.in/yaml.v3"
+)
 
 // HooksConfig is an alias for map of hook names to slices of hook configurations.
 // It supports unmarshalling both legacy single-hook and newer multi-hook formats.
 type HooksConfig map[string][]*HookConfig
 
 // UnmarshalYAML converts hook configuration from YAML, supporting both single-hook configuration
 // and multiple-hooks configuration.
+//
+// Each hook entry is independently parsed as either a single HookConfig (mapping node) or a list
+// of HookConfigs (sequence node), allowing mixed formats within the same hooks: block.
 func (ch *HooksConfig) UnmarshalYAML(unmarshal func(any) error) error {
-	var legacyConfig map[string]*HookConfig
+	// Unmarshal into map[string]any so each value retains its Go representation:
+	//   YAML mapping  → map[string]any
+	//   YAML sequence → []any
+	//   YAML null     → nil
+	var raw map[string]any
+	if err := unmarshal(&raw); err != nil {
+		return fmt.Errorf("failed to unmarshal hooks configuration: %w", err)
+	}
 
-	if err := unmarshal(&legacyConfig); err == nil {
-		newConfig := HooksConfig{}
+	result := make(HooksConfig, len(raw))
 
-		for key, value := range legacyConfig {
-			newConfig[key] = []*HookConfig{value}
-		}
+	for key, val := range raw {
+		switch val.(type) {
+		case nil:
+			// A null YAML value (e.g. "preprovision:" with no body).
+			// Preserve with a nil entry so downstream validation can report it.
+			result[key] = []*HookConfig{nil}
 
-		*ch = newConfig
-		return nil
-	}
+		case map[string]any:
+			// Single hook configuration (a YAML mapping).
+			encoded, encErr := yaml.Marshal(val)
+			if encErr != nil {
+				return fmt.Errorf("failed to unmarshal hook %q: %w", key, encErr)
+			}
 
-	var newConfig map[string][]*HookConfig
-	if err := unmarshal(&newConfig); err != nil {
-		return fmt.Errorf("failed to unmarshal hooks configuration: %w", err)
+			var single HookConfig
+			if err := yaml.Unmarshal(encoded, &single); err != nil {
+				return fmt.Errorf("failed to unmarshal hook %q: %w", key, err)
+			}
+
+			result[key] = []*HookConfig{&single}
+
+		case []any:
+			// List of hook configurations (a YAML sequence).
+			encoded, encErr := yaml.Marshal(val)
+			if encErr != nil {
+				return fmt.Errorf("failed to unmarshal hook %q: %w", key, encErr)
+			}
+
+			var list []*HookConfig
+			if err := yaml.Unmarshal(encoded, &list); err != nil {
+				return fmt.Errorf("failed to unmarshal hook %q: %w", key, err)
+			}
+
+			result[key] = list
+
+		default:
+			return fmt.Errorf(
+				"failed to unmarshal hook %q: expected mapping or sequence, got %T",
+				key, val,
+			)
+		}
 	}
 
-	*ch = newConfig
+	*ch = result
 
 	return nil
 }