fixup! make shim opt-in via process.env

Author: erights

packages/non-trapping-shim/README.md

@@ -1,4 +1,4 @@
-# Shim for Non-trapping Integrity Trait
+# Opt-in Shim for Non-trapping Integrity Trait
 
 Emulates support for the non-trapping integrity trait from the
 [Stabilize proposal](https://github.com/tc39/proposal-stabilize).
@@ -11,4 +11,11 @@ This package is currently organized internally as a ponyfill, and a shim based o
 
 See https://github.com/endojs/endo/blob/master/packages/ses/docs/preparing-for-stabilize.md for guidance on how to prepare for the changes that will be introduced by this proposal.
 
-TODO: More explanation.
+## Opt-in env-option `SES_NON_TRAPPING_SHIM`
+
+To cope with various compat problems in linking code that uses or assumes this shim to code that does not, we have made this shim opt-in via the env-option `SES_NON_TRAPPING_SHIM`. This has two settings, `'enabled'` and the default `'disabled'`. As with all env options, this is represented at the property `process.env.SES_NON_TRAPPING_SHIM`, which typically represents the environment variable `SES_NON_TRAPPING_SHIM`. Thus, if nothing else sets `process.env.SES_NON_TRAPPING_SHIM`, you can opt-in at the shell level by
+```sh
+$ export SES_NON_TRAPPING_SHIM=enabled
+```
+
+When not opted into, importing the shim has no effect.

packages/non-trapping-shim/package.json

@@ -20,6 +20,7 @@
   "module": "./index.js",
   "exports": {
     "./shim.js": "./shim.js",
+    "./prepare-enable-shim.js": "./prepare-enable-shim.js",
     "./package.json": "./package.json"
   },
   "scripts": {
@@ -35,6 +36,9 @@
     "test:c8": "c8 $C8_OPTIONS ava --config=ava-nesm.config.js",
     "test:xs": "exit 0"
   },
+  "dependencies": {
+    "@endo/env-options": "workspace:^"
+  },
   "devDependencies": {
     "ava": "^6.1.3",
     "c8": "^7.14.0",

packages/non-trapping-shim/prepare-enable-shim.js

@@ -0,0 +1,7 @@
+/* global globalThis */
+
+// TODO consider adding env option setting APIs to @endo/env-options
+// TODO should set up globalThis.process.env if absent
+const env = (globalThis.process || {}).env || {};
+
+env.SES_NON_TRAPPING_SHIM = 'enabled';

packages/non-trapping-shim/shim.js

@@ -1,10 +1,22 @@
 /* global globalThis */
+import { getEnvironmentOption } from '@endo/env-options';
 import { ReflectPlus, ObjectPlus, ProxyPlus } from './src/non-trapping-pony.js';
 
-globalThis.Reflect = ReflectPlus;
+const nonTrappingShimOption = getEnvironmentOption(
+  'SES_NON_TRAPPING_SHIM',
+  'disabled',
+  ['enabled'],
+);
 
-globalThis.Object = ObjectPlus;
-// eslint-disable-next-line no-extend-native
-Object.prototype.constructor = ObjectPlus;
+if (nonTrappingShimOption === 'enabled') {
+  // TODO figure this out, either remove directive or change to
+  // at-ts-expect-error.
+  // @ts-ignore type of ReflectPlus vs Reflect, I think
+  globalThis.Reflect = ReflectPlus;
 
-globalThis.Proxy = ProxyPlus;
+  globalThis.Object = ObjectPlus;
+  // eslint-disable-next-line no-extend-native
+  Object.prototype.constructor = ObjectPlus;
+
+  globalThis.Proxy = ProxyPlus;
+}

packages/non-trapping-shim/test/non-trapping-shim.test.js

@@ -1,3 +1,4 @@
+import '../prepare-enable-shim.js';
 // Uses 'ava' rather than @endo/ses-ava to avoid worries about cyclic
 // dependencies. We will need similar tests is higher level packages, in order
 // to test compat with ses and ses-ava.

yarn.lock

@@ -706,6 +706,7 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@endo/non-trapping-shim@workspace:packages/non-trapping-shim"
   dependencies:
+    "@endo/env-options": "workspace:^"
     ava: "npm:^6.1.3"
     c8: "npm:^7.14.0"
     tsd: "npm:^0.31.2"