docs: finalize plugin policy & birth unification rules; runner default auto; boot no-cache disabled; ensure_loaded reprobe(FileBox); VM always birth after new; CURRENT_TASK updated

Author: nyash-codex

CURRENT_TASK.md

@@ -336,3 +336,34 @@ apps/selfhost/hakorune-vm/
 - 既存 from の互換（非strict）を維持、strict で Fail‑Fast が働く
 
 - Builtin callAsync true async implemented (HAKO_CALLABLE_ASYNC=1): job queue + VM polling; added smoke quick/core/callable_async_builtin_vm.sh.
+
+---
+
+## Plugin Policy & Birth Unification (Phase 15.7) — Plan & Status
+
+Goals
+- Default plugin policy = auto (ON). If no providers configured, no side-effects.
+- VM unifies lifecycle: new → birth(me,args) always (birth missing = no-op, idempotent)
+- Plugin init: load-time nyash_plugin_init() (optional) and first-birth ensure_ready() (Once)
+- Provider resolution single order: Plugin → Builtin → Registry; on-demand reprobe for T
+- Boot disabled state is not cached (allow later retry when policy flips to ON)
+
+Done
+- Runner: default policy auto (None/unknown → auto)
+- Boot: policy off no longer cached as success (returns false; retry later)
+- ProviderBox: reprobe list extended to include FileBox
+- VM: always attempt birth after new (ignore missing method)
+- Smokes: plugins/filebox_write_read_vm added; quick/core/filebox stabilized (SKIP when unavailable)
+- Docs updated: docs/reference/plugin-system/vm-plugin-integration.md (final rules)
+
+Next
+- Determinism guard (deny IO caps like FileBox when HAKO_DETERMINISTIC=1)
+- Error ergonomics: ProviderNotFound/PluginInitFailed/BirthFailed with provenance
+- Optional: on-demand reprobe toggle for deterministic mode (off)
+
+Acceptance
+- plugins profile: all smokes green (callable/map/string/array/json/filebox)
+- quick profile: filebox_basic is PASS or SKIP (plugin missing)
+- Runner: default plugin policy is auto; no regressions
+- VM: new→birth unified; no double-birth
+

docs/reference/plugin-system/vm-plugin-integration.md

@@ -2,6 +2,17 @@
 
 Note: Terminology updated — “Nyash ABI” is now referred to as “Hako ABI (formerly Nyash ABI)”.
 
+## Policy & Lifecycle — Final Rules (Phase 15.7)
+
+- Plugin Policy: default ON (auto). If no plugins are configured in hako.toml/nyash.toml, nothing is loaded (no side‑effects). CI などで完全遮断したい場合のみ `NYASH_DISABLE_PLUGINS=1` を使う。
+- Creation: `new T(args…)` is always followed by `birth(me,args…)` by VM. When `birth` is not implemented, it is treated as no‑op (idempotent). Builder の auto‑birth は既定OFF。
+- Plugin Init: two idempotent stages are allowed (optional)
+  - Load‑time: `nyash_plugin_init()` called once per library when present
+  - First‑birth: plugin may call `ensure_ready()` guarded by `Once`
+- Provider Resolution: single order — `PluginProvider(T) → BuiltinProvider(T) → Registry/Fallback(T) → error`. Before resolving, the registry performs on‑demand re‑probe for `T` to avoid timing issues.
+- Boot Disabled Non‑cache: boot() no longer caches “disabled” as success (allows later retry when policy flips to ON). Operationally we run with policy=auto by default so this path is rarely used.
+
+
 ## 🎯 概要
 
 NyashのVMバックエンドとプラグインシステム（BID-FFI v1）の統合に関する技術仕様。Everything is Box哲学に基づき、**すべてのBox型（ビルトイン、ユーザー定義、プラグイン）**をVMで統一的に扱えるようにする。

src/backend/mir_interpreter/handlers/boxes/newbox.rs

@@ -24,6 +24,8 @@ impl MirInterpreter {
                 self.regs.insert(dst, created_vm.clone());
                 if let VMValue::BoxRef(arc_box) = &created_vm { self.scope.register_box(arc_box.clone()); }
                 crate::backend::mir_interpreter::helpers::lifecycle_contracts_box::LifecycleContractsBox::mark_new(self, dst, box_type, args.len());
+                // Always attempt birth; ignore missing method
+                let _ = self.handle_box_call(None, dst, "birth", args);
                 crate::backend::mir_interpreter::helpers::lifecycle_contracts_box::LifecycleContractsBox::born_if_no_birth(self, dst, box_type, args.len());
                 return Ok(());
             }
@@ -93,14 +95,8 @@ impl MirInterpreter {
         // Centralized lifecycle observation (contracts + traces)
         crate::backend::mir_interpreter::helpers::lifecycle_contracts_box::LifecycleContractsBox::mark_new(self, dst, box_type, args.len());
 
-        // Dev-only: optional auto birth after NewBox to unblock selfhost paths
-        // Guarded by NYASH_VM_AUTO_BIRTH_DEV=1. In production, builders must
-        // materialize explicit birth calls.
-        if super::super::VmConfig::global().auto_birth_dev {
-            // Dev: call birth with the same args that were provided to NewBox
-            // This covers user-defined boxes that rely on birth parameters
-            let _ = self.handle_box_call(None, dst, "birth", args);
-        }
+        // Always attempt birth after creation; ignore missing method to keep no-op semantics.
+        let _ = self.handle_box_call(None, dst, "birth", args);
 
         // C++-style constructor mode (interim): optionally invoke ModuleFunction
         // "Class.birth/N" immediately after NewBox, using fully qualified name.

src/runner/plugins.rs

@@ -24,12 +24,13 @@ impl NyashRunner {
         // Plugins (guarded)
         // Default policy: OFF (plugins disabled) unless explicitly set to auto/force.
         // Aliases handled by env core bootstrap (HAKO_* → NYASH_*), but we defensively read both.
+        // Policy: default ON (auto). Unknown/empty -> treat as auto.
         let policy = std::env::var("NYASH_PLUGIN_POLICY").ok().or_else(|| std::env::var("HAKO_PLUGIN_POLICY").ok());
         let disable_by_policy = match policy.as_deref() {
-            None => true, // default OFF in Hakorune build
             Some(s) if s.eq_ignore_ascii_case("off") => true,
             Some(s) if s.eq_ignore_ascii_case("auto") || s.eq_ignore_ascii_case("force") => false,
-            _ => true, // unknown → OFF
+            None => false, // default to auto
+            _ => false,    // unknown → consider auto (fail-open; providers may still be empty)
         };
         if !disable_by_policy && std::env::var("NYASH_DISABLE_PLUGINS").ok().as_deref() != Some("1") {
             runner_plugin_init::init_bid_plugins();

src/runtime/plugin_boot_box/mod.rs

@@ -20,8 +20,9 @@ fn policy_on() -> bool {
 pub fn boot() -> bool {
     if let Some(v) = BOOTED.get() { return *v; }
 
+    if !policy_on() { return false; }
+
     let ok = (|| {
-        if !policy_on() { return true; } // treat as success when policy off
 
         // Choose config candidates (prefer explicit override)
         let mut tried: Vec<String> = Vec::new();

src/runtime/provider_box/mod.rs

@@ -17,7 +17,7 @@ pub fn ensure_loaded(_config_path: Option<&str>) {
     if crate::runtime::env_gate_box::plugins_disabled() { return; }
     if !crate::runtime::env_gate_box::plugin_policy_on() { return; }
     let _ = crate::runtime::plugin_boot_box::boot();
-    let _ = crate::runtime::plugin_boot_box::reprobe_providers_for(["ArrayBox", "MapBox", "StringBox"].as_ref());
+    let _ = crate::runtime::plugin_boot_box::reprobe_providers_for(["ArrayBox", "MapBox", "StringBox", "FileBox"].as_ref());
 }
 
 /// Create a box using Plugin → Registry → Embedded order (best‑effort)