fix(review): address feedback from reviews 2788, 2789, 2791

- Move nodeCount increment after cycle detection to avoid over-counting
  cyclic references (sonnet #2)
- Use underscores in test case names used as filenames (sonnet #3)
- Fix function comment: 'prevent silent data loss' → 'prevent confusing
  behavior where additional documents are silently ignored' (sonnet #4)
- Mark design doc pseudocode as historical since implementation uses
  goccy/go-yaml ast.Node, not gopkg.in/yaml.v3 yaml.Node (sonnet #5)

docs/DESIGN-57-yaml-persona.md

@@ -33,6 +33,11 @@ func parsePersona(data []byte, source string) (*Persona, error) {
 
 ### YAML Parsing with Depth Protection
 
+> **Note:** The pseudocode below reflects the initial design using `gopkg.in/yaml.v3`
+> types (`yaml.Node`). The actual implementation uses `github.com/goccy/go-yaml`
+> with `ast.Node`-based traversal, dual-map cycle/depth tracking, and node-count
+> limits. See `review/persona.go` for the current implementation.
+
 ```go
 func unmarshalYAMLWithDepthLimit(data []byte, out any, maxDepth int) error {
     var node yaml.Node

review/persona.go

@@ -161,7 +161,8 @@ func parsePersona(data []byte, source string) (*Persona, error) {
 // unmarshalYAMLWithDepthLimit unmarshals YAML data with explicit depth limiting
 // and strict field checking. This protects against stack exhaustion from deeply
 // nested structures and catches typos in field names.
-// Multi-document YAML files are rejected to prevent silent data loss.
+// Multi-document YAML files are rejected to prevent confusing behavior
+// where additional documents are silently ignored.
 func unmarshalYAMLWithDepthLimit(data []byte, out any, maxDepth int) error {
 	// First pass: parse into AST to check depth limits, node counts, and
 	// multi-document rejection. This prevents stack exhaustion before we
@@ -214,12 +215,6 @@ func checkYAMLDepth(node ast.Node, depth, maxDepth, maxNodes int, validated map[
 		return fmt.Errorf("YAML nesting depth exceeds maximum (%d)", maxDepth)
 	}
 
-	// Track total nodes visited as defense-in-depth against wide-but-shallow attacks.
-	*nodeCount++
-	if *nodeCount > maxNodes {
-		return fmt.Errorf("YAML node count exceeds maximum (%d)", maxNodes)
-	}
-
 	// Cycle detection: if we're currently visiting this node on the current
 	// recursion path, it's a cycle (e.g., alias pointing to an ancestor).
 	// Return nil to break the cycle without error — cycles are a structural
@@ -228,6 +223,13 @@ func checkYAMLDepth(node ast.Node, depth, maxDepth, maxNodes int, validated map[
 		return nil
 	}
 
+	// Track total nodes visited as defense-in-depth against wide-but-shallow attacks.
+	// Placed after cycle detection to avoid over-counting cyclic references.
+	*nodeCount++
+	if *nodeCount > maxNodes {
+		return fmt.Errorf("YAML node count exceeds maximum (%d)", maxNodes)
+	}
+
 	// Depth-aware short-circuit: only skip re-checking a node if we previously
 	// validated it at the same or deeper effective depth. If this visit is at a
 	// greater depth than before (e.g., alias referenced deeper in the tree),

review/persona_test.go

@@ -491,9 +491,9 @@ func TestYAMLEmptyFileRejection(t *testing.T) {
 		name    string
 		content string
 	}{
-		{"completely empty", ""},
-		{"whitespace only", "   \n\n  "},
-		{"comment only", "# just a comment\n"},
+		{"completely_empty", ""},
+		{"whitespace_only", "   \n\n  "},
+		{"comment_only", "# just a comment\n"},
 	}
 
 	for _, tc := range tests {