From acc403c536778c082fbdf0cb0bfedbfddbfeedab Mon Sep 17 00:00:00 2001
From: virtualian <ian.marr@gmail.com>
Date: Sun, 26 Apr 2026 22:20:45 +0100
Subject: [PATCH] Fix SecurityValidator yaml import crash via lazy dynamic load
 (#156)
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Static `import { parse as parseYaml } from 'yaml'` crashed the hook at
module load on every PreToolUse:Read because no node_modules resolves
`yaml` from `~/.pai/hooks/`. Claude Code reported the error as
non-blocking, but the warning fired on every Read, polluting session
output.

Replace with a lazy dynamic import wrapped in try/catch:
- Type-only import via `import type { parse as YamlParse } from 'yaml'`
  (erased at parse time; cannot reintroduce the resolution warning)
- `ensureYamlLoaded()` awaits `import('yaml')` once at the top of `main()`
  and silently sets `parseYaml = null` on failure
- `loadPatterns()` short-circuits to a fail-open empty config when
  `parseYaml` is null, symmetric with the existing no-file and
  parse-error fail-open paths

The same edit is applied to the runtime `~/.pai/hooks/SecurityValidator.hook.ts`
so the warning stops in the current session; the runtime and shipped
copies remain byte-identical.

Verified empirically: hook returns `{"continue":true}` exit 0 with zero
stderr for Read/Bash/Write inputs (vs pre-fix `Cannot find package 'yaml'`
warning). Failing dynamic-import cost ~10ms total per invocation, well
inside the 200ms stdin window.

Audit confirms only `SecurityValidator.hook.ts` uses any third-party npm
package across all 17 PAI hooks — no other hooks affected.

Note: this fix silences the warning but does NOT restore SecurityValidator
to functional state. The validator has been silently a no-op since the
v3.0 → v4.x refactor stopped shipping `patterns.example.yaml`. Restoring
real pattern matching requires a separate PR that (a) makes `yaml`
resolvable from `~/.pai/hooks/` and (b) restores the patterns file under
`Releases/v4.0.3+/.claude/PAISECURITYSYSTEM/`. Tracked in follow-up issue.

Closes #156.
---
 .../.claude/hooks/SecurityValidator.hook.ts   | 26 ++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/Releases/v4.0.3+/.claude/hooks/SecurityValidator.hook.ts b/Releases/v4.0.3+/.claude/hooks/SecurityValidator.hook.ts
index 9c302d47..a8cf0756 100755
--- a/Releases/v4.0.3+/.claude/hooks/SecurityValidator.hook.ts
+++ b/Releases/v4.0.3+/.claude/hooks/SecurityValidator.hook.ts
@@ -63,9 +63,22 @@
 import { readFileSync, existsSync, writeFileSync, mkdirSync } from 'fs';
 import { join } from 'path';
 import { homedir } from 'os';
-import { parse as parseYaml } from 'yaml';
+import type { parse as YamlParse } from 'yaml';
 import { configPath, codePath } from './lib/paths';
 
+// Lazy yaml load — static `import 'yaml'` crashes module load when the package
+// isn't resolvable from this hook's directory.
+let parseYaml: typeof YamlParse | null = null;
+
+async function ensureYamlLoaded(): Promise<void> {
+  if (parseYaml) return;
+  try {
+    parseYaml = (await import('yaml')).parse;
+  } catch {
+    parseYaml = null;
+  }
+}
+
 // ========================================
 // Security Event Logging
 // ========================================
@@ -220,6 +233,16 @@ function loadPatterns(): PatternsConfig {
     };
   }
 
+  if (!parseYaml) {
+    return {
+      version: '0.0',
+      philosophy: { mode: 'permissive', principle: 'YAML parser unavailable - fail open' },
+      bash: { trusted: [], blocked: [], confirm: [], alert: [] },
+      paths: { zeroAccess: [], readOnly: [], confirmWrite: [], noDelete: [] },
+      projects: {}
+    };
+  }
+
   try {
     const content = readFileSync(patternsPath, 'utf-8');
     patternsCache = parseYaml(content) as PatternsConfig;
@@ -551,6 +574,7 @@ function handleRead(input: HookInput): void {
 // ========================================
 
 async function main(): Promise<void> {
+  await ensureYamlLoaded();
   let input: HookInput;
 
   try {