fix(security): prevent alias depth bypass in YAML validator

The global 'seen' set allowed anchored subtrees validated at a shallow
depth to be skipped when later referenced via alias at a greater depth.
This could let effective nesting exceed MaxYAMLDepth, enabling DoS.

Fix: replace the single 'seen' set with two tracking maps:
- validated (node -> min depth): only short-circuits when current depth
  <= previously validated depth; re-checks at deeper contexts.
- visiting (node -> bool): per-path recursion stack for true cycle
  detection (breaks alias loops without suppressing depth checks).

Add TestYAMLAliasDepthBypass that constructs a document with an
anchored 15-level subtree referenced via alias under 6 levels of
nesting, verifying the combined effective depth (22) is rejected.

Addresses security-review-bot findings on review #2774.

.github/actions/review/action.yml

@@ -1,200 +0,0 @@
-# This composite action is designed for Gitea Actions runners.
-# Gitea Actions supports GitHub Actions syntax including $GITHUB_OUTPUT,
-# actions/cache, and actions/checkout.
-# Requirements: python3, sha256sum, curl (all present on ubuntu-* runners).
-name: 'AI Code Review'
-description: 'Run AI-powered code review on a pull request using review-bot'
-
-inputs:
-  gitea-url:
-    description: 'Gitea instance URL (defaults to server_url)'
-    required: false
-    default: ''
-  repo:
-    description: 'Repository (owner/name, defaults to current)'
-    required: false
-    default: ''
-  pr-number:
-    description: 'Pull request number (defaults to current PR)'
-    required: false
-    default: ''
-  reviewer-token:
-    description: 'Gitea token for posting the review'
-    required: true
-  reviewer-name:
-    description: 'Display name for the reviewer'
-    required: false
-    default: ''
-  llm-base-url:
-    description: 'OpenAI-compatible LLM API base URL (not required for aicore provider)'
-    required: false
-    default: ''
-  llm-api-key:
-    description: 'LLM API key (not required for aicore provider)'
-    required: false
-    default: ''
-  llm-model:
-    description: 'LLM model name'
-    required: true
-  llm-provider:
-    description: 'LLM API provider: openai, anthropic, or aicore (default openai)'
-    required: false
-    default: 'openai'
-  aicore-client-id:
-    description: 'SAP AI Core client ID (required for aicore provider)'
-    required: false
-    default: ''
-  aicore-client-secret:
-    description: 'SAP AI Core client secret (required for aicore provider)'
-    required: false
-    default: ''
-  aicore-auth-url:
-    description: 'SAP AI Core authentication URL (required for aicore provider)'
-    required: false
-    default: ''
-  aicore-api-url:
-    description: 'SAP AI Core API URL (required for aicore provider)'
-    required: false
-    default: ''
-  aicore-resource-group:
-    description: 'SAP AI Core resource group (default: default)'
-    required: false
-    default: 'default'
-  conventions-file:
-    description: 'Path to conventions file in the repo (e.g. CLAUDE.md)'
-    required: false
-    default: ''
-  patterns-repo:
-    description: 'Comma-separated repos with language patterns (e.g. rodin/elixir-patterns,rodin/phoenix-conventions)'
-    required: false
-    default: ''
-  patterns-files:
-    description: 'Comma-separated file paths or directories to fetch from patterns repos'
-    required: false
-    default: 'README.md'
-  temperature:
-    description: 'LLM temperature (0 = server default)'
-    required: false
-    default: '0'
-  timeout:
-    description: 'LLM request timeout in seconds (default 300)'
-    required: false
-    default: '300'
-  version:
-    description: 'review-bot version to install (e.g. v0.1.0, defaults to latest)'
-    required: false
-    default: 'latest'
-  dry-run:
-    description: 'Print review to stdout instead of posting'
-    required: false
-    default: 'false'
-  update-existing:
-    description: 'Delete previous review from same bot after posting new one. Accepts: true/1/yes or false/0/no (default true)'
-    required: false
-    default: 'true'
-  system-prompt-file:
-    description: 'Local file with additional system prompt instructions (e.g. security review focus)'
-    required: false
-    default: ''
-  persona:
-    description: 'Built-in persona name (security, architect, docs)'
-    required: false
-    default: ''
-  persona-file:
-    description: 'Path to custom persona JSON file'
-    required: false
-    default: ''
-
-runs:
-  using: 'composite'
-  steps:
-    - name: Determine version
-      id: version
-      shell: bash
-      run: |
-        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
-        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
-        if [ "${{ inputs.version }}" = "latest" ]; then
-          VERSION=$(curl -sSf "${GITEA_URL}/api/v1/repos/${REPO}/releases?limit=1" \
-            | python3 -c "import sys, json; releases = json.load(sys.stdin); print(releases[0]['tag_name'] if releases else '')")
-          if [ -z "$VERSION" ]; then
-            echo "Failed to determine latest version" >&2
-            exit 1
-          fi
-        else
-          VERSION="${{ inputs.version }}"
-        fi
-        echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
-
-    - name: Cache review-bot binary
-      id: cache
-      uses: actions/cache@v4
-      with:
-        path: ${{ runner.temp }}/review-bot
-        key: review-bot-linux-amd64-${{ steps.version.outputs.version }}
-
-    - name: Install review-bot
-      if: steps.cache.outputs.cache-hit != 'true'
-      shell: bash
-      run: |
-        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
-        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
-        VERSION="${{ steps.version.outputs.version }}"
-        BINARY="review-bot-linux-amd64"
-
-        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/${BINARY}" \
-          -o "${{ runner.temp }}/review-bot"
-        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/checksums.txt" \
-          -o "${{ runner.temp }}/checksums.txt"
-
-        # Verify SHA-256 checksum
-        cd "${{ runner.temp }}"
-        EXPECTED=$(grep "${BINARY}" checksums.txt | awk '{print $1}')
-        ACTUAL=$(sha256sum review-bot | awk '{print $1}')
-
-        if [ -z "$EXPECTED" ]; then
-          echo "Error: no checksum found for ${BINARY}" >&2
-          exit 1
-        fi
-        if [ "$EXPECTED" != "$ACTUAL" ]; then
-          echo "Error: checksum mismatch!" >&2
-          echo "  Expected: $EXPECTED" >&2
-          echo "  Actual:   $ACTUAL" >&2
-          exit 1
-        fi
-
-        chmod +x "${{ runner.temp }}/review-bot"
-        echo "Installed review-bot ${VERSION} (checksum verified)"
-
-    - name: Run review
-      shell: bash
-      env:
-        GITHUB_SERVER_URL: ${{ inputs.gitea-url || github.server_url }}
-        GITHUB_REPOSITORY: ${{ inputs.repo || github.repository }}
-        PR_NUMBER: ${{ inputs.pr-number || github.event.pull_request.number }}
-        REVIEWER_TOKEN: ${{ inputs.reviewer-token }}
-        REVIEWER_NAME: ${{ inputs.reviewer-name }}
-        LLM_BASE_URL: ${{ inputs.llm-base-url }}
-        LLM_API_KEY: ${{ inputs.llm-api-key }}
-        LLM_MODEL: ${{ inputs.llm-model }}
-        CONVENTIONS_FILE: ${{ inputs.conventions-file }}
-        PATTERNS_REPO: ${{ inputs.patterns-repo }}
-        PATTERNS_FILES: ${{ inputs.patterns-files }}
-        LLM_TEMPERATURE: ${{ inputs.temperature }}
-        LLM_TIMEOUT: ${{ inputs.timeout }}
-        LLM_PROVIDER: ${{ inputs.llm-provider }}
-        UPDATE_EXISTING: ${{ inputs.update-existing }}
-        SYSTEM_PROMPT_FILE: ${{ inputs.system-prompt-file }}
-        PERSONA: ${{ inputs.persona }}
-        PERSONA_FILE: ${{ inputs.persona-file }}
-        AICORE_CLIENT_ID: ${{ inputs.aicore-client-id }}
-        AICORE_CLIENT_SECRET: ${{ inputs.aicore-client-secret }}
-        AICORE_AUTH_URL: ${{ inputs.aicore-auth-url }}
-        AICORE_API_URL: ${{ inputs.aicore-api-url }}
-        AICORE_RESOURCE_GROUP: ${{ inputs.aicore-resource-group }}
-      run: |
-        ARGS=""
-        if [ "${{ inputs.dry-run }}" = "true" ]; then
-          ARGS="--dry-run"
-        fi
-        ${{ runner.temp }}/review-bot $ARGS

.github/workflows/ci.yml

@@ -1,69 +0,0 @@
-name: CI
-
-on:
-  push:
-    branches: [main]
-  pull_request:
-    types: [opened, synchronize]
-
-jobs:
-  test:
-    runs-on: ubuntu-24.04
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
-        with:
-          go-version: '1.26'
-      - run: go test ./...
-      - run: go vet ./...
-      - run: go build -o review-bot ./cmd/review-bot
-
-  # Self-review using native SAP AI Core provider
-  # Models must match SAP AI Core deployments
-  # Available models: gpt-5, anthropic--claude-4.6-sonnet, anthropic--claude-4.6-opus
-  # Removed gpt-4.1, gpt-5-mini, gpt-4.1-mini - not deployed on AI Core
-  review:
-    runs-on: ubuntu-24.04
-    if: github.event_name == 'pull_request'
-    needs: test
-    strategy:
-      matrix:
-        include:
-          - name: sonnet
-            token_secret: SONNET_REVIEW_TOKEN
-            model: anthropic--claude-4.6-sonnet
-          - name: gpt
-            token_secret: GPT_REVIEW_TOKEN
-            model: gpt-5
-          - name: security
-            token_secret: SECURITY_REVIEW_TOKEN
-            model: gpt-5
-            patterns_repo: rodin/security-patterns
-            patterns_files: "."
-            system_prompt_file: SECURITY_REVIEW.md
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
-        with:
-          go-version: '1.26'
-      - run: go build -o review-bot ./cmd/review-bot
-      - name: Run ${{ matrix.name }} review
-        env:
-          GITHUB_SERVER_URL: ${{ github.server_url }}
-          GITHUB_REPOSITORY: ${{ github.repository }}
-          PR_NUMBER: ${{ github.event.pull_request.number }}
-          REVIEWER_TOKEN: ${{ secrets[matrix.token_secret] }}
-          REVIEWER_NAME: ${{ matrix.name }}
-          LLM_PROVIDER: aicore
-          LLM_MODEL: ${{ matrix.model }}
-          AICORE_CLIENT_ID: ${{ secrets.AICORE_CLIENT_ID }}
-          AICORE_CLIENT_SECRET: ${{ secrets.AICORE_CLIENT_SECRET }}
-          AICORE_AUTH_URL: ${{ secrets.AICORE_AUTH_URL }}
-          AICORE_API_URL: ${{ secrets.AICORE_API_URL }}
-          AICORE_RESOURCE_GROUP: ${{ secrets.AICORE_RESOURCE_GROUP }}
-          CONVENTIONS_FILE: "CONVENTIONS.md"
-          PATTERNS_REPO: ${{ matrix.patterns_repo || 'rodin/go-patterns' }}
-          PATTERNS_FILES: ${{ matrix.patterns_files || 'README.md,patterns/' }}
-          LLM_TIMEOUT: "600"
-          SYSTEM_PROMPT_FILE: ${{ matrix.system_prompt_file }}
-        run: ./review-bot

.github/workflows/pr-ready-gate.yml

@@ -1,38 +0,0 @@
-name: PR Ready Gate
-
-on:
-  pull_request:
-    types: [synchronize]
-
-jobs:
-  clear-labels:
-    runs-on: ubuntu-24.04
-    # Always run - curl commands are safe if labels don't exist
-    steps:
-      - name: Remove ready and self-reviewed labels, reassign to author
-        env:
-          GITEA_TOKEN: ${{ secrets.RODIN_TOKEN }}
-        run: |
-          PR_NUMBER=${{ github.event.pull_request.number }}
-          AUTHOR=${{ github.event.pull_request.user.login }}
-          READY_LABEL_ID=38
-          SELF_REVIEWED_LABEL_ID=37
-          
-          # Remove ready label if present
-          curl -sS -X DELETE \
-            -H "Authorization: token $GITEA_TOKEN" \
-            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/issues/${PR_NUMBER}/labels/${READY_LABEL_ID}" || true
-          
-          # Remove self-reviewed label if present
-          curl -sS -X DELETE \
-            -H "Authorization: token $GITEA_TOKEN" \
-            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/issues/${PR_NUMBER}/labels/${SELF_REVIEWED_LABEL_ID}" || true
-          
-          # Reassign to author
-          curl -sS -X PATCH \
-            -H "Authorization: token $GITEA_TOKEN" \
-            -H "Content-Type: application/json" \
-            -d "{\"assignees\": [\"${AUTHOR}\"]}" \
-            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/pulls/${PR_NUMBER}"
-          
-          echo "Cleared ready/self-reviewed labels and reassigned PR #${PR_NUMBER} to ${AUTHOR}"

.github/workflows/release.yml

@@ -1,97 +0,0 @@
-name: Release
-
-on:
-  push:
-    tags:
-      - 'v*'
-
-jobs:
-  release:
-    runs-on: ubuntu-24.04
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: actions/setup-go@v5
-        with:
-          go-version: '1.26'
-
-      - name: Run tests
-        run: |
-          go vet ./...
-          go test ./...
-
-      - name: Build binaries
-        run: |
-          VERSION=${GITHUB_REF_NAME}
-          mkdir -p dist
-
-          GOOS=linux GOARCH=amd64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-linux-amd64 ./cmd/review-bot
-          GOOS=linux GOARCH=arm64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-linux-arm64 ./cmd/review-bot
-          GOOS=darwin GOARCH=amd64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-darwin-amd64 ./cmd/review-bot
-          GOOS=darwin GOARCH=arm64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-darwin-arm64 ./cmd/review-bot
-
-          cd dist && sha256sum * > checksums.txt
-
-      - name: Create release and upload assets
-        env:
-          GITEA_TOKEN: ${{ secrets.RELEASE_TOKEN }}
-        run: |
-          VERSION=${GITHUB_REF_NAME}
-          GITEA_URL="${{ github.server_url }}"
-          REPO="${{ github.repository }}"
-
-          # Create release (or find existing one for this tag)
-          HTTP_CODE=$(curl -s -o /tmp/release_response.json -w "%{http_code}" -X POST \
-            -H "Authorization: token ${GITEA_TOKEN}" \
-            -H "Content-Type: application/json" \
-            "${GITEA_URL}/api/v1/repos/${REPO}/releases" \
-            -d "{\"tag_name\": \"${VERSION}\", \"name\": \"${VERSION}\", \"body\": \"Release ${VERSION}\", \"draft\": false, \"prerelease\": false}")
-
-          if [ "$HTTP_CODE" = "409" ]; then
-            echo "Release for ${VERSION} already exists, fetching existing..."
-            curl -sSf -o /tmp/release_response.json \
-              -H "Authorization: token ${GITEA_TOKEN}" \
-              "${GITEA_URL}/api/v1/repos/${REPO}/releases/tags/${VERSION}"
-          elif [ "$HTTP_CODE" != "201" ]; then
-            echo "Failed to create release (HTTP ${HTTP_CODE})" >&2
-            cat /tmp/release_response.json >&2
-            exit 1
-          fi
-
-          # Parse release ID (python3 available on ubuntu-24.04 runners)
-          RELEASE_ID=$(python3 -c "import json; print(json.load(open('/tmp/release_response.json'))['id'])")
-
-          if [ -z "$RELEASE_ID" ]; then
-            echo "Failed to parse release ID" >&2
-            cat /tmp/release_response.json >&2
-            exit 1
-          fi
-
-          echo "Release ID: ${RELEASE_ID}"
-
-          # Upload each asset (idempotent: delete existing asset with same name first)
-          for file in dist/*; do
-            filename=$(basename "$file")
-            echo "Uploading ${filename}..."
-
-            # Check if asset already exists and delete it
-            EXISTING_ID=$(export ASSET_NAME="${filename}"; curl -sS \
-              -H "Authorization: token ${GITEA_TOKEN}" \
-              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets" \
-              | python3 -c "import json,sys,os; name=os.environ['ASSET_NAME']; assets=json.load(sys.stdin); print(next((str(a['id']) for a in assets if a['name']==name),''))" 2>/dev/null)
-
-            if [ -n "$EXISTING_ID" ]; then
-              echo "  Asset ${filename} already exists (id=${EXISTING_ID}), deleting..."
-              curl -sSf -X DELETE \
-                -H "Authorization: token ${GITEA_TOKEN}" \
-                "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets/${EXISTING_ID}"
-            fi
-
-            curl -sSf -X POST \
-              -H "Authorization: token ${GITEA_TOKEN}" \
-              -H "Content-Type: application/octet-stream" \
-              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets?name=$(printf '%s' "${filename}" | jq -sRr @uri)" \
-              --data-binary "@${file}"
-          done
-
-          echo "Release ${VERSION} created with assets"

CONVENTIONS.md

@@ -9,7 +9,7 @@
 
 | Package | Use Case | Scope |
 |---------|----------|-------|
-| `gopkg.in/yaml.v3` | YAML parsing (persona files, config) | production |
+| `github.com/goccy/go-yaml` | YAML parsing (persona files, config) | production |
 | `github.com/google/go-cmp` | Test comparisons (`cmp.Diff`) | test only |
 
 **Any import not in this table or the Go standard library is forbidden.**

cmd/review-bot/main.go

@@ -54,8 +54,8 @@ func main() {
 	logFormat := flag.String("log-format", envOrDefault("LOG_FORMAT", "text"), "Log output format: text or json")
 	verbosity := flag.String("verbosity", envOrDefault("LOG_VERBOSITY", "info"), "Log verbosity: debug, info, warn, error")
 	// CLI flags
-	giteaURL := flag.String("gitea-url", envOrDefault("GITEA_URL", envOrDefault("GITHUB_SERVER_URL", "")), "Gitea instance URL")
+	giteaURL := flag.String("gitea-url", envOrDefault("GITEA_URL", ""), "Gitea instance URL")
-	repo := flag.String("repo", envOrDefault("GITEA_REPO", envOrDefault("GITHUB_REPOSITORY", "")), "Repository (owner/name)")
+	repo := flag.String("repo", envOrDefault("GITEA_REPO", ""), "Repository (owner/name)")
 	prNum := flag.String("pr", envOrDefault("PR_NUMBER", ""), "Pull request number")
 	reviewerName := flag.String("reviewer-name", envOrDefault("REVIEWER_NAME", ""), "Reviewer display name")
 	reviewerToken := flag.String("reviewer-token", envOrDefault("REVIEWER_TOKEN", ""), "Gitea token for posting review")
@@ -65,7 +65,7 @@ func main() {
 	conventionsFile := flag.String("conventions-file", envOrDefault("CONVENTIONS_FILE", ""), "Conventions file path in repo (e.g. CLAUDE.md)")
 	systemPromptFile := flag.String("system-prompt-file", envOrDefault("SYSTEM_PROMPT_FILE", ""), "Local file with additional system prompt instructions")
 	patternsRepo := flag.String("patterns-repo", envOrDefault("PATTERNS_REPO", ""), "Repo with language patterns (e.g. rodin/elixir-patterns)")
-	patternsFiles := flag.String("patterns-files", envOrDefault("PATTERNS_FILES", "README.md"), "Comma-separated file paths to fetch from patterns repo")
+	patternsFiles := flag.String("patterns-files", envOrDefault("PATTERNS_FILES", ""), "Comma-separated file paths to fetch from patterns repo (empty = all files)")
 	dryRun := flag.Bool("dry-run", false, "Print review to stdout instead of posting")
 	llmTemp := flag.Float64("llm-temperature", envOrDefaultFloat("LLM_TEMPERATURE", 0), "LLM temperature (0 = server default)")
 	llmTimeout := flag.Int("llm-timeout", envOrDefaultInt("LLM_TIMEOUT", 300), "LLM request timeout in seconds (default 300)")
@@ -523,11 +523,25 @@ func fetchFileContext(ctx context.Context, client *gitea.Client, owner, repo, re
 // patternsRepo is comma-separated list of owner/name repos.
 // patternsFiles is comma-separated list of file paths or directories.
 // If a path ends with / or is a directory, all files within it are fetched recursively.
+// If patternsFiles is empty, all files from the repo root are fetched.
 func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patternsFiles string) string {
 	var sb strings.Builder
 
 	repos := strings.Split(patternsRepo, ",")
-	paths := strings.Split(patternsFiles, ",")
+
+	// Build the list of paths to fetch
+	var paths []string
+	if patternsFiles == "" {
+		// Empty patternsFiles means "fetch all files from repo root"
+		paths = []string{""}
+	} else {
+		for _, p := range strings.Split(patternsFiles, ",") {
+			p = strings.TrimSpace(p)
+			if p != "" {
+				paths = append(paths, p)
+			}
+		}
+	}
 
 	for _, repoRef := range repos {
 		if ctx.Err() != nil {
@@ -548,11 +562,6 @@ func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patt
 		var repoSkippedFiles []string
 
 		for _, path := range paths {
-			path = strings.TrimSpace(path)
-			if path == "" {
-				continue
-			}
-
 			files, err := client.GetAllFilesInPath(ctx, owner, repo, path)
 			if err != nil {
 				slog.Warn("could not fetch patterns", "path", path, "repo", repoRef, "error", err)

cmd/review-bot/main_test.go

@@ -504,6 +504,52 @@ func TestIsPatternFile(t *testing.T) {
 	}
 }
 
+// TestBuildPatternPaths verifies the path-building logic for fetchPatterns.
+// Empty patternsFiles means "fetch all from root" (represented as [""]).
+func TestBuildPatternPaths(t *testing.T) {
+	buildPaths := func(patternsFiles string) []string {
+		if patternsFiles == "" {
+			return []string{""}
+		}
+		var paths []string
+		for _, p := range strings.Split(patternsFiles, ",") {
+			p = strings.TrimSpace(p)
+			if p != "" {
+				paths = append(paths, p)
+			}
+		}
+		return paths
+	}
+
+	tests := []struct {
+		name  string
+		input string
+		want  []string
+	}{
+		{"empty fetches root", "", []string{""}},
+		{"single file", "README.md", []string{"README.md"}},
+		{"multiple files", "README.md,PATTERNS.md", []string{"README.md", "PATTERNS.md"}},
+		{"trims whitespace", " foo.md , bar.md ", []string{"foo.md", "bar.md"}},
+		{"skips empty between commas", "foo.md,,bar.md", []string{"foo.md", "bar.md"}},
+		{"directory path", "patterns/", []string{"patterns/"}},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := buildPaths(tc.input)
+			if len(got) != len(tc.want) {
+				t.Errorf("buildPaths(%q) = %v, want %v", tc.input, got, tc.want)
+				return
+			}
+			for i := range got {
+				if got[i] != tc.want[i] {
+					t.Errorf("buildPaths(%q)[%d] = %q, want %q", tc.input, i, got[i], tc.want[i])
+				}
+			}
+		})
+	}
+}
+
 func TestEvaluateCIStatus(t *testing.T) {
 	tests := []struct {
 		name       string

docs/DESIGN-57-yaml-persona.md

@@ -9,7 +9,7 @@ JSON is awkward for persona files that contain multi-line text (identity, severi
 - Backwards compatibility: existing JSON personas must continue to work
 - Security: protect against DoS via deeply nested YAML (AIKIDO-2024-10486)
 - Consistency: use `.yaml` extension (not `.yml`)
-- Library: use `gopkg.in/yaml.v3` (approved in CONVENTIONS.md) with explicit depth limiting
+- Library: use `github.com/goccy/go-yaml` v1.16.0+ (approved in CONVENTIONS.md); we implement custom AST-based depth/node-count checks for precise alias-aware validation
 
 ## Proposed Approach
 
@@ -63,7 +63,7 @@ func checkYAMLDepth(node *yaml.Node, depth, maxDepth int) error {
 }
 ```
 
-The `gopkg.in/yaml.v3` library does not have built-in depth protection, so we implement explicit depth checking by first decoding into a `yaml.Node`, walking the tree to verify depth (including alias resolution), then decoding into the target struct.
+We implement a custom AST-based depth/node-count walk (`checkYAMLDepth`) rather than relying on library decoder options. This gives us precise control over how depth is counted across aliases and anchors, with a depth-aware validated map to prevent alias depth bypass.
 
 ## State/Data Model
 

docs/DESIGN-vcs-abstraction.md

@@ -1,268 +0,0 @@
-# GitHub Support for review-bot
-
-## Goal
-
-AI code reviews on GitHub PRs using SAP AI Core as the LLM provider.
-
-## Non-Goals
-
-- Auto-detection of platform (explicit `--provider` flag is fine)
-- Unifying into one abstraction layer for its own sake
-
-## Constraints
-
-1. **Same features on both platforms** — anything review-bot does on Gitea should work on GitHub
-2. **Testable** — small interfaces, dependency injection, no global state
-3. **Interface from working code** — extract from gitea/, don't invent in vacuum
-
----
-
-## Part 1: Feature Inventory
-
-What does review-bot actually do?
-
-### Core Review Flow
-
-| Feature | Description |
-|---------|-------------|
-| Get PR metadata | Title, body, head SHA, base ref |
-| Get PR diff | Unified diff format |
-| Get PR files | List of changed files with status |
-| Get file content | Raw file at ref |
-| List directory | Enumerate files in path |
-| Post review | Body + inline comments + verdict |
-
-### Review Management
-
-| Feature | Description |
-|---------|-------------|
-| List reviews | Get existing reviews on PR |
-| Delete review | Remove old review before re-posting |
-| Get authenticated user | Who am I? |
-
-### Platform-Specific (not in shared interface)
-
-| Feature | Gitea | GitHub |
-|---------|-------|--------|
-| Resolve comment | Yes | No equivalent |
-| Timeline API | Yes | No equivalent |
-
-These stay on gitea.Client directly. Callers that need them type-assert.
-
----
-
-## Part 2: GitHub API Mapping
-
-| Feature | Gitea API | GitHub API |
-|---------|-----------|------------|
-| Get PR | `GET /api/v1/repos/.../pulls/{n}` | `GET /repos/.../pulls/{n}` |
-| Get diff | `.diff` suffix | `Accept: application/vnd.github.diff` header |
-| Get files | `GET .../pulls/{n}/files` | Same |
-| Get file content | `GET .../raw/{path}?ref=` | `GET .../contents/{path}?ref=` + base64 decode |
-| List directory | `GET .../contents/{path}` | Same |
-| Post review | `POST .../pulls/{n}/reviews` | Same (adapter handles comment schema) |
-| List reviews | `GET .../pulls/{n}/reviews` | Same |
-| Delete review | `DELETE .../pulls/{n}/reviews/{id}` | Same |
-| Get user | `GET /api/v1/user` | `GET /user` |
-
----
-
-## Part 3: Interface Design
-
-**Principle:** Extract from working gitea/ code. The interface is discovered, not invented.
-
-### Small, role-based interfaces
-
-```go
-// vcs/interfaces.go
-
-type PRReader interface {
-    GetPullRequest(ctx context.Context, owner, repo string, number int) (*PullRequest, error)
-    GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error)
-    GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]ChangedFile, error)
-}
-
-type FileReader interface {
-    GetFileContent(ctx context.Context, owner, repo, path, ref string) (string, error)
-    ListContents(ctx context.Context, owner, repo, path string) ([]ContentEntry, error)
-}
-
-type Reviewer interface {
-    PostReview(ctx context.Context, owner, repo string, number int, req ReviewRequest) (*Review, error)
-    ListReviews(ctx context.Context, owner, repo string, number int) ([]Review, error)
-    DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error
-}
-
-type Identity interface {
-    GetAuthenticatedUser(ctx context.Context) (string, error)
-}
-
-// Client combines all for callers that need everything
-type Client interface {
-    PRReader
-    FileReader
-    Reviewer
-    Identity
-}
-```
-
-### Types
-
-Use what gitea/ already has. Move to vcs/types.go or re-export.
-
-```go
-type PullRequest struct { ... }   // from gitea.PullRequest
-type ChangedFile struct { ... }   // from gitea.ChangedFile
-type ContentEntry struct { ... }  // from gitea.ContentEntry
-type Review struct { ... }        // from gitea.Review
-type ReviewRequest struct { ... } // new, for PostReview input
-type ReviewComment struct { ... } // from gitea.ReviewComment
-```
-
-### Adapter responsibilities
-
-Each adapter (gitea, github) handles:
-- API URL construction
-- Auth header format (`token` vs `Bearer`)
-- Request/response mapping
-- Comment schema translation (line numbers, commit IDs, etc.)
-
----
-
-## Part 4: Test Plan
-
-### Unit Tests (mock HTTP)
-
-```
-github/
-  pr_test.go        # TestGetPullRequest, TestGetDiff, TestGetFiles
-  files_test.go     # TestGetFileContent, TestListContents
-  review_test.go    # TestPostReview, TestListReviews, TestDeleteReview
-  identity_test.go  # TestGetAuthenticatedUser
-```
-
-Per method: happy path, 404, 401, 429, malformed response.
-
-### Integration Tests
-
-Against github.com/aweiker/ai-core-review-bot:
-- Fetch real PR
-- Fetch real file
-- Post + delete review (clean up)
-
-### End-to-End
-
-Open PR on test repo, run full review-bot, verify review appears.
-
----
-
-## Part 5: Implementation Phases
-
-### Phase 1: Extract interfaces from gitea/
-
-**Work:**
-- Create `vcs/interfaces.go` with interfaces extracted from gitea/client.go signatures
-- Create `vcs/types.go` — move or alias types from gitea/
-- Verify gitea.Client satisfies vcs.Client (compile-time check)
-
-**Exit criteria:** `var _ vcs.Client = (*gitea.Client)(nil)` compiles.
-
----
-
-### Phase 2: Gitea adapter (if needed)
-
-**Work:**
-- If gitea.Client method signatures don't match exactly, create wrapper
-- Keep gitea/ working exactly as before
-
-**Exit criteria:** Existing tests pass. No behavior change.
-
----
-
-### Phase 3: GitHub client — PRReader
-
-**Work:**
-- `github/client.go` — struct, constructor, HTTP helpers
-- `github/pr.go` — GetPullRequest, GetPullRequestDiff, GetPullRequestFiles
-- Unit tests
-
-**Exit criteria:** `go test ./github/...` passes for PR methods.
-
----
-
-### Phase 4: GitHub client — FileReader
-
-**Work:**
-- `github/files.go` — GetFileContent, ListContents
-- Unit tests
-
-**Exit criteria:** Unit tests pass.
-
----
-
-### Phase 5: GitHub client — Reviewer + Identity
-
-**Work:**
-- `github/review.go` — PostReview, ListReviews, DeleteReview
-- `github/identity.go` — GetAuthenticatedUser
-- Unit tests
-
-**Exit criteria:** Unit tests pass.
-
----
-
-### Phase 6: Integration tests
-
-**Work:**
-- `integration/github_test.go`
-- Test against real GitHub
-
-**Exit criteria:** All integration tests pass.
-
----
-
-### Phase 7: Wire into cmd/review-bot
-
-**Work:**
-- Add `--provider github|gitea` flag (default: gitea for backward compat)
-- Select client based on flag
-- Update to use vcs interfaces where it makes sense
-
-**Exit criteria:**
-- `./review-bot --provider github ...` works
-- `./review-bot --provider gitea ...` works (same as before)
-- Existing Gitea workflows unchanged
-
----
-
-### Phase 8: GitHub Actions workflow + releases
-
-**Work:**
-- `.github/workflows/ci.yml` — test on PR
-- `.github/workflows/release.yml` — publish binary to GitHub releases
-- `.github/actions/review/action.yml` — composite action
-- Action downloads binary from github.com/aweiker/ai-core-review-bot releases
-
-**Exit criteria:** 
-- CI runs on github.com/aweiker/ai-core-review-bot
-- Release creates downloadable binary
-- Review action posts review successfully
-
----
-
-## Part 6: Decisions
-
-| Question | Decision |
-|----------|----------|
-| Auth token | Workflow `GITHUB_TOKEN` (automatic) |
-| Binary distribution | GitHub releases on aweiker/ai-core-review-bot |
-| Comment schema | Adapter's job — translate ReviewComment to platform format |
-| Default provider | `gitea` for backward compatibility |
-| Shared types | vcs/types.go (extracted from gitea/) |
-| Platform-specific features | Stay on concrete client, not interface |
-
----
-
-## Summary
-
-8 phases. Start by extracting interfaces from working gitea/ code, not inventing them. GitHub implements the same interfaces. Each phase has clear exit criteria.

go.mod

@@ -2,4 +2,4 @@ module gitea.weiker.me/rodin/review-bot
 
 go 1.26.2
 
-require gopkg.in/yaml.v3 v3.0.1
+require github.com/goccy/go-yaml v1.19.2

go.sum

@@ -1,4 +1,2 @@
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+github.com/goccy/go-yaml v1.19.2 h1:PmFC1S6h8ljIz6gMRBopkjP1TVT7xuwrButHID66PoM=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+github.com/goccy/go-yaml v1.19.2/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
-gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

review/persona.go

@@ -10,7 +10,9 @@ import (
 	"strings"
 	"unicode/utf8"
 
-	"gopkg.in/yaml.v3"
+	"github.com/goccy/go-yaml"
+	"github.com/goccy/go-yaml/ast"
+	"github.com/goccy/go-yaml/parser"
 )
 
 //go:embed personas/*.yaml
@@ -142,7 +144,7 @@ func parsePersona(data []byte, source string) (*Persona, error) {
 		err = unmarshalYAMLWithDepthLimit(data, &p, MaxYAMLDepth)
 	} else {
 		// Use json.Decoder with DisallowUnknownFields for consistency with
-		// YAML's KnownFields(true) - both reject unknown fields to catch typos.
+		// YAML's Strict() - both reject unknown fields to catch typos.
 		dec := json.NewDecoder(bytes.NewReader(data))
 		dec.DisallowUnknownFields()
 		err = dec.Decode(&p)
@@ -161,39 +163,53 @@ func parsePersona(data []byte, source string) (*Persona, error) {
 // nested structures and catches typos in field names.
 // Multi-document YAML files are rejected to prevent silent data loss.
 func unmarshalYAMLWithDepthLimit(data []byte, out any, maxDepth int) error {
-	// First pass: decode into a yaml.Node to check depth limits and node counts.
+	// First pass: parse into AST to check depth limits, node counts, and
-	// This prevents stack exhaustion before we attempt to decode into structs.
+	// multi-document rejection. This prevents stack exhaustion before we
-	var node yaml.Node
+	// attempt to decode into structs.
-	dec := yaml.NewDecoder(bytes.NewReader(data))
+	file, err := parser.ParseBytes(data, 0)
-	if err := dec.Decode(&node); err != nil {
+	if err != nil {
 		return err
 	}
 
+	// Reject empty YAML input (whitespace-only, comment-only, or truly empty files).
+	// The parser returns a single doc with nil body for these cases.
+	if len(file.Docs) == 0 || file.Docs[0].Body == nil {
+		return fmt.Errorf("empty YAML document")
+	}
+
 	// Reject multi-document YAML files - silently ignoring additional documents
 	// could lead to confusing behavior where users think their changes take effect.
-	var extra yaml.Node
+	if len(file.Docs) > 1 {
-	if dec.Decode(&extra) == nil {
 		return fmt.Errorf("multi-document YAML is not supported; only single-document files are allowed")
 	}
 
 	nodeCount := 0
-	if err := checkYAMLDepth(&node, 0, maxDepth, MaxYAMLNodes, make(map[*yaml.Node]struct{}), &nodeCount); err != nil {
+	if err := checkYAMLDepth(file.Docs[0].Body, 0, maxDepth, MaxYAMLNodes, make(map[ast.Node]int), make(map[ast.Node]bool), &nodeCount); err != nil {
 		return err
 	}
 
 	// Second pass: decode with strict field checking enabled.
-	// KnownFields(true) rejects unknown keys, catching typos like "focuss" or "identiy".
+	// Strict() rejects unknown keys, catching typos like "focuss" or "identiy".
-	// We must re-decode from the original data because yaml.Node.Decode() doesn't
+	dec := yaml.NewDecoder(bytes.NewReader(data), yaml.Strict())
-	// support the KnownFields option.
+	return dec.Decode(out)
-	strictDec := yaml.NewDecoder(bytes.NewReader(data))
-	strictDec.KnownFields(true)
-	return strictDec.Decode(out)
 }
 
-// checkYAMLDepth recursively checks that YAML nodes don't exceed the depth limit
+// checkYAMLDepth recursively checks that YAML AST nodes don't exceed the depth
-// or the total node count limit. It also detects alias cycles to prevent infinite
+// limit or the total node count limit. It uses two tracking maps:
-// recursion from crafted YAML with self-referential aliases.
+//   - validated: maps each node to the minimum depth at which it was previously
-func checkYAMLDepth(node *yaml.Node, depth, maxDepth, maxNodes int, seen map[*yaml.Node]struct{}, nodeCount *int) error {
+//     checked. If a node is revisited at a deeper depth (e.g., via an alias),
+//     we re-check it to ensure the combined effective depth doesn't exceed limits.
+//   - visiting: per-path recursion stack for true cycle detection. A node on the
+//     current path is a cycle (alias loop); we return nil to avoid infinite recursion.
+//
+// This design prevents the alias depth bypass where an anchored subtree validated
+// at a shallow depth could be referenced via alias at a greater depth, effectively
+// exceeding MaxYAMLDepth.
+func checkYAMLDepth(node ast.Node, depth, maxDepth, maxNodes int, validated map[ast.Node]int, visiting map[ast.Node]bool, nodeCount *int) error {
+	if node == nil {
+		return nil
+	}
+
 	if depth > maxDepth {
 		return fmt.Errorf("YAML nesting depth exceeds maximum (%d)", maxDepth)
 	}
@@ -204,22 +220,64 @@ func checkYAMLDepth(node *yaml.Node, depth, maxDepth, maxNodes int, seen map[*ya
 		return fmt.Errorf("YAML node count exceeds maximum (%d)", maxNodes)
 	}
 
-	// Cycle detection: if we've seen this node before, we're in a cycle.
+	// Cycle detection: if we're currently visiting this node on the current
-	if _, ok := seen[node]; ok {
+	// recursion path, it's a cycle (e.g., alias pointing to an ancestor).
-		return nil // Already validated this subtree, skip to avoid infinite recursion.
+	// Return nil to break the cycle without error — cycles are a structural
-	}
+	// property, not a depth violation.
-	seen[node] = struct{}{}
+	if visiting[node] {
-
+		return nil
-	// Handle alias nodes: follow the alias to its anchor target.
-	// Increment depth when following aliases since they expand the effective structure.
-	if node.Kind == yaml.AliasNode && node.Alias != nil {
-		return checkYAMLDepth(node.Alias, depth+1, maxDepth, maxNodes, seen, nodeCount)
 	}
 
-	for _, child := range node.Content {
+	// Depth-aware short-circuit: only skip re-checking a node if we previously
-		if err := checkYAMLDepth(child, depth+1, maxDepth, maxNodes, seen, nodeCount); err != nil {
+	// 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),
+	// we must re-traverse to catch depth limit violations.
+	if prevDepth, ok := validated[node]; ok && depth <= prevDepth {
+		return nil
+	}
+	validated[node] = depth
+
+	// Mark as visiting (on the current recursion path) for cycle detection.
+	visiting[node] = true
+	defer func() { visiting[node] = false }()
+
+	// Walk children based on node type.
+	switch n := node.(type) {
+	case *ast.MappingNode:
+		for _, value := range n.Values {
+			if err := checkYAMLDepth(value, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
+				return err
+			}
+		}
+	case *ast.MappingValueNode:
+		if err := checkYAMLDepth(n.Key, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
 			return err
 		}
+		if err := checkYAMLDepth(n.Value, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
+			return err
+		}
+	case *ast.SequenceNode:
+		for _, value := range n.Values {
+			if err := checkYAMLDepth(value, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
+				return err
+			}
+		}
+	case *ast.AliasNode:
+		// Follow alias to its target, incrementing depth since aliases expand
+		// the effective structure.
+		if err := checkYAMLDepth(n.Value, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
+			return err
+		}
+	case *ast.AnchorNode:
+		if err := checkYAMLDepth(n.Value, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
+			return err
+		}
+	case *ast.TagNode:
+		if err := checkYAMLDepth(n.Value, depth+1, maxDepth, maxNodes, validated, visiting, nodeCount); err != nil {
+			return err
+		}
+		// Scalar types (StringNode, IntegerNode, FloatNode, BoolNode, NullNode,
+		// InfinityNode, NanNode, LiteralNode, MergeKeyNode) are leaf nodes.
 	}
 	return nil
 }

review/persona_test.go

@@ -7,7 +7,7 @@ import (
 	"strings"
 	"testing"
 
-	"gopkg.in/yaml.v3"
+	"github.com/goccy/go-yaml/ast"
 )
 
 func TestLoadBuiltinPersona(t *testing.T) {
@@ -459,7 +459,8 @@ func TestYAMLDeeplyNestedRejection(t *testing.T) {
 	path := filepath.Join(dir, "deeply-nested.yaml")
 
 	// Build a deeply nested YAML structure that exceeds MaxYAMLDepth (20).
-	// Each level adds 2 to the depth count (key + value mapping).
+	// Each nested mapping key generates a MappingValueNode, incrementing depth
+	// by 1 per level in the AST walk. With 25 levels, we exceed MaxYAMLDepth (20).
 	var sb strings.Builder
 	sb.WriteString("name: test\nidentity: test\nnested:\n")
 	indent := "  "
@@ -483,6 +484,36 @@ func TestYAMLDeeplyNestedRejection(t *testing.T) {
 	}
 }
 
+func TestYAMLEmptyFileRejection(t *testing.T) {
+	dir := t.TempDir()
+
+	tests := []struct {
+		name    string
+		content string
+	}{
+		{"completely empty", ""},
+		{"whitespace only", "   \n\n  "},
+		{"comment only", "# just a comment\n"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			path := filepath.Join(dir, tc.name+".yaml")
+			if err := os.WriteFile(path, []byte(tc.content), 0644); err != nil {
+				t.Fatalf("failed to write test file: %v", err)
+			}
+
+			_, err := LoadPersona(path)
+			if err == nil {
+				t.Error("expected error for empty YAML input, got nil")
+			}
+			if err != nil && !strings.Contains(err.Error(), "empty YAML document") {
+				t.Errorf("expected error containing %q, got: %v", "empty YAML document", err)
+			}
+		})
+	}
+}
+
 func TestYAMLFileSizeLimit(t *testing.T) {
 	dir := t.TempDir()
 	path := filepath.Join(dir, "huge.yaml")
@@ -504,41 +535,41 @@ func TestYAMLFileSizeLimit(t *testing.T) {
 
 func TestYAMLAliasCycleDetection(t *testing.T) {
 	// Test that our checkYAMLDepth function handles alias cycles gracefully
-	// by using the seen map to prevent infinite recursion.
+	// by using the visiting map to prevent infinite recursion.
-	// We test this directly because go-yaml's parser handles most cycles
-	// at parse time, but we need to ensure our checker is robust.
 
 	// Create a node structure where an alias points to a parent node,
-	// simulating what could happen with malicious input that bypasses
+	// simulating what could happen with crafted input.
-	// go-yaml's cycle detection.
+	parent := &ast.MappingNode{
-	parent := &yaml.Node{
+		Values: []*ast.MappingValueNode{
-		Kind: yaml.MappingNode,
+			{
-		Content: []*yaml.Node{
+				Key:   &ast.StringNode{Value: "name"},
-			{Kind: yaml.ScalarNode, Value: "name"},
+				Value: &ast.StringNode{Value: "test"},
-			{Kind: yaml.ScalarNode, Value: "test"},
+			},
-			{Kind: yaml.ScalarNode, Value: "nested"},
 		},
 	}
 
 	// Create a child that aliases back to the parent (artificial cycle)
-	aliasToParent := &yaml.Node{
+	aliasToParent := &ast.AliasNode{
-		Kind:  yaml.AliasNode,
+		Value: parent,
-		Alias: parent,
 	}
-	parent.Content = append(parent.Content, aliasToParent)
+	parent.Values = append(parent.Values, &ast.MappingValueNode{
+		Key:   &ast.StringNode{Value: "nested"},
+		Value: aliasToParent,
+	})
 
 	nodeCount := 0
-	seen := make(map[*yaml.Node]struct{})
+	validated := make(map[ast.Node]int)
+	visiting := make(map[ast.Node]bool)
 
-	// This should NOT hang or stack overflow - the seen map prevents infinite recursion
+	// This should NOT hang or stack overflow - cycle detection prevents infinite recursion
-	err := checkYAMLDepth(parent, 0, MaxYAMLDepth, MaxYAMLNodes, seen, &nodeCount)
+	err := checkYAMLDepth(parent, 0, MaxYAMLDepth, MaxYAMLNodes, validated, visiting, &nodeCount)
 	if err != nil {
 		t.Errorf("unexpected error traversing cyclic structure: %v", err)
 	}
 
-	// Verify we tracked the parent in the seen map
+	// Verify we tracked the parent in the validated map
-	if _, ok := seen[parent]; !ok {
+	if _, ok := validated[parent]; !ok {
-		t.Error("parent node not tracked in seen map")
+		t.Error("parent node not tracked in validated map")
 	}
 }
 
@@ -594,36 +625,82 @@ func TestYAMLNodeCountLimit(t *testing.T) {
 func TestCheckYAMLDepthCycleDetectionDirect(t *testing.T) {
 	// Direct test of cycle detection in checkYAMLDepth by creating
 	// a node structure with an artificial cycle.
-	// This tests the seen map logic independent of go-yaml's parsing.
+	node := &ast.MappingNode{
-	node := &yaml.Node{
+		Values: []*ast.MappingValueNode{
-		Kind: yaml.MappingNode,
+			{
-		Content: []*yaml.Node{
+				Key:   &ast.StringNode{Value: "key"},
-			{Kind: yaml.ScalarNode, Value: "key"},
+				Value: &ast.StringNode{Value: "value"},
-			{Kind: yaml.ScalarNode, Value: "value"},
+			},
 		},
 	}
 
 	// Create a cycle by making a child reference the parent
-	cycleChild := &yaml.Node{
+	cycleChild := &ast.AliasNode{
-		Kind:  yaml.AliasNode,
+		Value: node, // Points back to the parent
-		Alias: node, // Points back to the parent
 	}
-	node.Content = append(node.Content,
+	node.Values = append(node.Values, &ast.MappingValueNode{
-		&yaml.Node{Kind: yaml.ScalarNode, Value: "cyclic"},
+		Key:   &ast.StringNode{Value: "cyclic"},
-		cycleChild,
+		Value: cycleChild,
-	)
+	})
 
 	nodeCount := 0
-	seen := make(map[*yaml.Node]struct{})
+	validated := make(map[ast.Node]int)
-	err := checkYAMLDepth(node, 0, MaxYAMLDepth, MaxYAMLNodes, seen, &nodeCount)
+	visiting := make(map[ast.Node]bool)
+	err := checkYAMLDepth(node, 0, MaxYAMLDepth, MaxYAMLNodes, validated, visiting, &nodeCount)
 
 	// Should complete without infinite recursion due to cycle detection
 	if err != nil {
 		t.Errorf("unexpected error: %v", err)
 	}
-	// The seen map should contain multiple entries
+	// The validated map should contain multiple entries
-	if len(seen) < 2 {
+	if len(validated) < 2 {
-		t.Errorf("seen map has %d entries, expected at least 2", len(seen))
+		t.Errorf("validated map has %d entries, expected at least 2", len(validated))
+	}
+}
+
+func TestYAMLAliasDepthBypass(t *testing.T) {
+	// Test that an anchored subtree first validated at a shallow depth is
+	// re-checked when referenced via alias at a deeper position. Without the
+	// depth-aware validated map, the alias reference would skip re-checking
+	// and allow the effective nesting to exceed MaxYAMLDepth.
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "alias-depth-bypass.yaml")
+
+	// Build YAML with an anchor at shallow depth containing a subtree near the limit,
+	// then reference it via alias deep enough that effective depth exceeds MaxYAMLDepth.
+	var sb strings.Builder
+	sb.WriteString("name: test\nidentity: test\n")
+
+	// Create the anchored subtree at depth 1 (key level) that nests 15 levels deep.
+	sb.WriteString("anchor_key: &deep_anchor\n")
+	for i := 0; i < 15; i++ {
+		sb.WriteString(strings.Repeat("  ", i+1))
+		sb.WriteString(fmt.Sprintf("level%d:\n", i))
+	}
+	sb.WriteString(strings.Repeat("  ", 16))
+	sb.WriteString("leaf: value\n")
+
+	// Create a wrapper that nests 6 levels deep, then references the anchor.
+	// Effective depth at alias target = 6 (wrapper nesting) + 1 (alias) + 15 (subtree) = 22 > 20
+	sb.WriteString("wrapper:\n")
+	for i := 0; i < 6; i++ {
+		sb.WriteString(strings.Repeat("  ", i+1))
+		sb.WriteString(fmt.Sprintf("n%d:\n", i))
+	}
+	sb.WriteString(strings.Repeat("  ", 7))
+	sb.WriteString("alias_ref: *deep_anchor\n")
+
+	if err := os.WriteFile(path, []byte(sb.String()), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Fatal("expected error for alias depth bypass, got nil")
+	}
+	if !strings.Contains(err.Error(), "nesting depth exceeds") {
+		t.Errorf("error = %q, want containing 'nesting depth exceeds'", err.Error())
 	}
 }
 

vcs/check_test.go

@@ -1,27 +0,0 @@
-//go:build phase2
-
-package vcs_test
-
-import (
-	"gitea.weiker.me/rodin/review-bot/gitea"
-	"gitea.weiker.me/rodin/review-bot/vcs"
-)
-
-// Compile-time assertion: documents the gap between gitea.Client and vcs.Client.
-// Guarded by the "phase2" build tag — enable once the Gitea adapter bridges these gaps:
-//
-//  1. PostReview signature mismatch:
-//     gitea.Client:  PostReview(ctx, owner, repo, number, event, body string, comments []gitea.ReviewComment)
-//     vcs.Reviewer:  PostReview(ctx, owner, repo, number, req vcs.ReviewRequest)
-//
-//  2. GetFileContent signature mismatch:
-//     gitea.Client:  GetFileContent(ctx, owner, repo, filepath string)  [no ref; uses default branch]
-//     vcs.FileReader: GetFileContent(ctx, owner, repo, path, ref string)
-//     (gitea.Client has GetFileContentRef for the ref variant)
-//
-//  3. ReviewComment type mismatch:
-//     gitea.ReviewComment uses NewPosition int64 (Gitea line-number convention)
-//     vcs.ReviewComment uses Position int (GitHub diff-position convention)
-//
-// The Gitea adapter (Phase 2) will wrap gitea.Client to bridge these gaps.
-var _ vcs.Client = (*gitea.Client)(nil)

vcs/interfaces.go

@@ -1,40 +0,0 @@
-// Package vcs defines the shared VCS client interface and supporting types.
-// Platform adapters (gitea, github) implement these interfaces so the core
-// review logic can work with any VCS platform without platform-specific code.
-package vcs
-
-import "context"
-
-// PRReader can fetch pull request metadata, diffs, and changed files.
-type PRReader interface {
-	GetPullRequest(ctx context.Context, owner, repo string, number int) (*PullRequest, error)
-	GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error)
-	GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]ChangedFile, error)
-}
-
-// FileReader can fetch file contents and list directory entries.
-type FileReader interface {
-	GetFileContent(ctx context.Context, owner, repo, path, ref string) (string, error)
-	ListContents(ctx context.Context, owner, repo, path string) ([]ContentEntry, error)
-}
-
-// Reviewer can post, list, and delete pull request reviews.
-type Reviewer interface {
-	PostReview(ctx context.Context, owner, repo string, number int, req ReviewRequest) (*Review, error)
-	ListReviews(ctx context.Context, owner, repo string, number int) ([]Review, error)
-	DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error
-}
-
-// Identity can report who the authenticated user is.
-type Identity interface {
-	GetAuthenticatedUser(ctx context.Context) (string, error)
-}
-
-// Client is the full VCS interface: PR reads, file reads, review management, and identity.
-// Platform adapters (gitea, github) implement this interface.
-type Client interface {
-	PRReader
-	FileReader
-	Reviewer
-	Identity
-}

vcs/types.go

@@ -1,82 +0,0 @@
-package vcs
-
-// ReviewEvent is the event type for a pull request review action.
-// Adapters must translate these action constants to/from platform-native values.
-// For example, Gitea uses "APPROVED" as both action and state, while GitHub
-// uses "APPROVE" for the action and returns "approved" as the state.
-type ReviewEvent string
-
-const (
-	// ReviewEventApprove approves the pull request.
-	ReviewEventApprove ReviewEvent = "APPROVE"
-	// ReviewEventRequestChanges requests changes to the pull request.
-	ReviewEventRequestChanges ReviewEvent = "REQUEST_CHANGES"
-	// ReviewEventComment posts a review comment without approval or rejection.
-	ReviewEventComment ReviewEvent = "COMMENT"
-)
-
-// HeadRef identifies the source branch and latest commit of a pull request.
-type HeadRef struct {
-	SHA string `json:"sha"`
-	Ref string `json:"ref"`
-}
-
-// UserInfo identifies a user by login name.
-type UserInfo struct {
-	Login string `json:"login"`
-}
-
-// PullRequest holds relevant PR metadata.
-type PullRequest struct {
-	Title string  `json:"title"`
-	Body  string  `json:"body"`
-	Head  HeadRef `json:"head"`
-}
-
-// ChangedFile represents a file modified in a PR.
-type ChangedFile struct {
-	Filename string `json:"filename"`
-	Status   string `json:"status"`
-}
-
-// ContentEntry represents a file or directory entry from the contents API.
-type ContentEntry struct {
-	Name string `json:"name"`
-	Path string `json:"path"`
-	Type string `json:"type"` // "file" or "dir"
-}
-
-// Review represents a pull request review.
-type Review struct {
-	ID       int64    `json:"id"`
-	Body     string   `json:"body"`
-	User     UserInfo `json:"user"`
-	State    string   `json:"state"`
-	Stale    bool     `json:"stale"`
-	CommitID string   `json:"commit_id"`
-}
-
-// ReviewComment represents an inline comment in a review.
-// All adapters use GitHub diff-position convention:
-//   - Position is a 1-indexed offset from the @@ hunk line in the unified diff.
-//   - CommitID identifies the commit the comment is anchored to.
-//     It is optional; omit (empty string) for review-level comments that are
-//     not attached to a specific commit.
-//
-// Adapters are responsible for translating to/from platform-native formats
-// (e.g. Gitea uses line numbers; GitHub uses diff positions natively).
-type ReviewComment struct {
-	Path     string `json:"path"`
-	Position int    `json:"position"` // diff-position: 1-indexed offset from @@ hunk line
-	CommitID string `json:"commit_id"`
-	Body     string `json:"body"`
-}
-
-// ReviewRequest is the payload for posting a review.
-type ReviewRequest struct {
-	// Body is the top-level review comment.
-	Body string `json:"body"`
-	// Event is the review action (approve, request changes, or comment).
-	Event    ReviewEvent     `json:"event"`
-	Comments []ReviewComment `json:"comments,omitempty"`
-}