[errors] Replace chalk import in @workfow/errors with inline ANSI shim (vercel#1915)

Author: VaguelySerious

.changeset/errors-no-chalk.md

@@ -0,0 +1,5 @@
+---
+"@workflow/errors": patch
+---
+
+Replace the `chalk` import in `@workflow/errors/ansi` with a tiny inline ANSI shim. `@workflow/errors/ansi` is reachable from the workflow-VM bundle (via `@workflow/core/workflow` → `context-errors` → `context-violation-error` → here), and `chalk` pulls in `supports-color`, which calls `require('os')` at module load — crashing every workflow with `ReferenceError: require is not defined` in the sandboxed VM.

packages/errors/__mocks__/chalk.ts

@@ -42,7 +42,6 @@
   },
   "dependencies": {
     "@workflow/utils": "workspace:*",
-    "chalk": "5.6.2",
     "ms": "2.1.3"
   }
 }

packages/errors/package.json

@@ -1,8 +1,30 @@
 import { describe, expect, it, vi } from 'vitest';
-import * as Ansi from './ansi.js';
 
-// Render ANSI styles as HTML-like tags in snapshots so they're readable.
-vi.mock('chalk');
+// Render styles as readable HTML-like tags in snapshots so a reviewer can
+// see at a glance which fragments are colored and how. The production
+// implementation in `./internal-chalk.ts` emits ANSI SGR escapes and
+// short-circuits to identity functions when there's no TTY (and in the
+// workflow VM, where `globalThis.process` is undefined).
+vi.mock('./internal-chalk.js', () => {
+  const tag =
+    (name: string) =>
+    (s: string): string =>
+      `<${name}>${s}</${name}>`;
+  return {
+    default: {
+      bold: tag('b'),
+      dim: tag('dim'),
+      italic: tag('i'),
+      red: tag('red'),
+      blue: tag('blue'),
+      cyan: tag('cyan'),
+      yellow: tag('yellow'),
+      magenta: tag('magenta'),
+    },
+  };
+});
+
+const Ansi = await import('./ansi.js');
 
 describe('Ansi.frame', () => {
   it('renders a single-line title with no contents', () => {
@@ -62,7 +84,10 @@ describe('Ansi.hint / note / help / docs', () => {
     expect(
       Ansi.note(['read more:', 'https://example.com'])
     ).toMatchInlineSnapshot(
-      `"<blue><b>note:</b> read more:\nhttps://example.com</blue>"`
+      `
+      "<blue><b>note:</b> read more:
+      https://example.com</blue>"
+    `
     );
   });
 

packages/errors/src/ansi.test.ts

@@ -1,4 +1,9 @@
-import chalk from 'chalk';
+// Imported from a sibling module rather than `chalk` proper so this file
+// (and everything that statically imports it — including the workflow-VM
+// reachable `context-violation-error.ts`) doesn't pull in chalk's
+// `supports-color` / `require('os')` chain. See `./internal-chalk.ts`
+// for the full rationale and the test mock that swaps it out.
+import chalk from './internal-chalk.js';
 
 /**
  * Helpers for composing structured, human-friendly error messages.

packages/errors/src/ansi.ts

@@ -0,0 +1,61 @@
+/**
+ * Tiny inline `chalk` replacement.
+ *
+ * `@workflow/errors/ansi` is reachable from the workflow-VM bundle (via
+ * `@workflow/core/workflow` → `context-errors` → `context-violation-error`
+ * → here), and the workflow VM has no `require()`. The real `chalk` package
+ * pulls in `supports-color`, which calls `require('os')` at module load —
+ * so importing `chalk` here crashes every workflow with
+ * `ReferenceError: require is not defined`.
+ *
+ * This module exposes the subset of chalk's call surface that `ansi.ts`
+ * uses (`bold`, `dim`, `italic`, `red`, `blue`, `cyan`, `yellow`,
+ * `magenta`). Color detection mirrors chalk's defaults at a coarse level:
+ * `FORCE_COLOR` forces on, `NO_COLOR` forces off, otherwise we emit ANSI
+ * only on a TTY stdout. In the workflow VM `process` is absent so this
+ * evaluates to "no color" and the helpers become identity functions —
+ * which is what the runtime wants anyway, since the host catches and
+ * re-renders the error.
+ *
+ * Exported from its own module so tests can replace it with `vi.mock` to
+ * render styles as readable HTML-like tags in snapshots without dragging
+ * `chalk` (and its transitive `supports-color` / `require('os')` chain)
+ * back into the workflow VM bundle.
+ */
+
+const colorEnabled = (() => {
+  const p = (globalThis as { process?: NodeJS.Process }).process;
+  if (!p?.env) return false;
+  if (p.env.FORCE_COLOR && p.env.FORCE_COLOR !== '0') return true;
+  if (p.env.NO_COLOR) return false;
+  return Boolean(p.stdout?.isTTY);
+})();
+
+const sgr =
+  (open: number, close: number) =>
+  (s: string): string =>
+    colorEnabled ? `\x1b[${open}m${s}\x1b[${close}m` : s;
+
+export interface InternalChalk {
+  bold: (s: string) => string;
+  dim: (s: string) => string;
+  italic: (s: string) => string;
+  red: (s: string) => string;
+  blue: (s: string) => string;
+  cyan: (s: string) => string;
+  yellow: (s: string) => string;
+  magenta: (s: string) => string;
+}
+
+const chalk: InternalChalk = {
+  bold: sgr(1, 22),
+  dim: sgr(2, 22),
+  italic: sgr(3, 23),
+  red: sgr(31, 39),
+  blue: sgr(34, 39),
+  cyan: sgr(36, 39),
+  yellow: sgr(33, 39),
+  magenta: sgr(35, 39),
+};
+
+export default chalk;