fix: bundle prettier into dist by removing it from esbuild external list

[Copilot]

The action fails immediately on startup with ERR_MODULE_NOT_FOUND: Cannot find package 'prettier' because esbuild was configured to treat prettier as external, leaving it unbundled. At runtime in user workflows, only dist/ is present — no node_modules — so the import resolves to nothing regardless of the pretty input value.

Changes

scripts/esbuild.mjs — remove prettier from the external array:

-    external: ['prettier'],
+    external: [],

prettier is already a dependency (not devDependency) in package.json, so bundling it is correct. The resulting dist/bin/index.js grows to ~29MB but is fully self-contained.

__tests__/integration-bundled-binary.test.ts — added a regression test that reproduces the original failure path:

• Copies the binary into an isolated temp directory with no node_modules anywhere in the directory hierarchy (mirroring the GitHub Actions runner environment where only dist/ is deployed)
• Runs the binary from that isolated directory
• Asserts that stderr contains no ERR_MODULE_NOT_FOUND and that the binary exits successfully with a generated README

The test was validated to fail against a binary built with external: ['prettier'] (reproducing the exact error from the issue) and pass against the fixed binary.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	81.76%	771 / 943
🔵	Statements	81.85%	776 / 948
🔵	Functions	83.19%	99 / 119
🔵	Branches	76.66%	368 / 480

File Coverage

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Generated in workflow #598 for commit 576a50c by the Vitest Coverage Report Action

[Jamie-BitFlight]

@copilot did the validation tests test the failure path accurately. did you trigger the error without the fix first to identify how the failure occurred

[Copilot]

Pull request overview

Fixes a runtime startup failure in the published GitHub Action by ensuring prettier is bundled into the generated dist/bin/index.js, so the action can run in user workflows where node_modules is not present.

Changes:

• Remove prettier from the esbuild external list so it is included in the bundle.

[Copilot]

@copilot did the validation tests test the failure path accurately. did you trigger the error without the fix first to identify how the failure occurred

No, I didn't reproduce the failure path first in my initial fix. I've now done that explicitly in commit 9a11fa2.

Here's what was done to validate the failure path:

1. Reproduced the original bug: Restored external: ['prettier'] in esbuild.mjs, rebuilt the binary (13MB), copied it to an isolated temp directory with no node_modules, and ran it — produced the exact error from the issue:

   Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'prettier' imported from .../index.js
   

   The key was copying the binary to a temp dir with no parent node_modules. Simply changing cwd isn't sufficient — Node.js resolves external modules relative to the binary's own location, walking up the directory tree. The GitHub Actions runner fails because no node_modules/prettier exists anywhere in the hierarchy above dist/bin/index.js.

2. Added a regression test (__tests__/integration-bundled-binary.test.ts) that:

   • Copies the binary into an isolated temp dir (no node_modules in the path)
   • Runs it from that temp dir
   • Asserts stderr contains no ERR_MODULE_NOT_FOUND

   Confirmed the test fails against the broken binary (with external: ['prettier']) and passes against the fixed one.

[Jamie-BitFlight]

@copilot your changes are failing the ci tests. please lint and format

[Copilot]

@copilot your changes are failing the ci tests. please lint and format

Fixed in 576a50c — removed the unused stdout variable that was triggering the lint/correctness/noUnusedVariables biome error. The execSync return value is now discarded (only stderr and exitCode from the catch block are needed).

[Jamie-BitFlight]

🎉 This PR is included in version 1.10.6 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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