fix(windows): repair PATHEXT in spawned shells + ESM ripgrep wrapper by wonderwhy-er · Pull Request #484 · wonderwhy-er/DesktopCommanderMCP

wonderwhy-er · 2026-05-31T13:22:50Z

Summary

Two Windows-specific fixes, both surfaced while investigating #481.

Investigates: #481

1. Repair corrupted `PATHEXT` before spawning shells (the #481 report)

On some Windows Claude Desktop / DXT launches, the Desktop Commander server
process inherits a broken PATHEXT (observed as .CPL only). Because
terminal-manager.ts builds each child shell's environment from
{ ...process.env }, that broken value propagated into every spawned shell,
stripping .EXE and breaking resolution of git / node / python / rg
(and even full-path .exe invocations under PowerShell).

Findings that refine the original report:

Not ARM64-specific — reproduced on AMD64/x64 as well. It affects the
Windows DXT v0.2.41 launch path generally.
DC's own code never sets PATHEXT; the value is inherited from how the DXT
host launches the server, then faithfully copied to children. Root cause is
upstream (Claude Desktop's DXT launcher), but DC is the right place to defend
since it controls the env handed to child shells.

Fix: on win32, repair PATHEXT immediately before spawn. If .EXE is
missing, merge the standard extension list with whatever was present
(non-destructive when PATHEXT is already healthy).

2. Make the bundled ripgrep wrapper ESM

@vscode/ripgrep 1.18.0+ ships package.json with "type": "module". The
MCPB build copies scripts/ripgrep-wrapper.js over the package's
lib/index.js, but the wrapper was CommonJS (require / module.exports), so
it threw require is not defined in ES module scope on import. That throw was
swallowed by getRipgrepPath()'s try/catch and surfaced as a misleading
ripgrep binary not found, silently breaking start_search on Windows even
though the bundled binaries were present.

Fix: rewrite the wrapper as ESM (import + export const rgPath,
__dirname via fileURLToPath). Verified with a fresh Node import against the
deployed extension: rgPath resolves to rg-x86_64-pc-windows-msvc.exe and the
binary exists.

Testing

tsc --noEmit: no new type errors from these changes.
ripgrep wrapper: validated via fresh import() against the bundled package on
Windows x64 — named rgPath export resolves and the target binary exists.
PATHEXT: confirmed the broken .CPL value at process level on x64, and that
restoring PATHEXT makes git/node/etc. resolve again.

Notes

Both fixes are Windows-only in effect; non-Windows behavior is unchanged.
The PATHEXT issue likely also warrants a parallel report to Claude Desktop's
DXT launcher, but this PR lets DC self-heal without waiting on that.

Summary by CodeRabbit

Bug Fixes
- Fixed Windows shell command resolution issues caused by corrupted inherited environment variables.
Improvements
- Enhanced ripgrep binary discovery with improved fallback logic for platform-specific binaries and clearer error messages when unavailable.

On some Windows Claude Desktop/DXT launches the server process inherits a broken PATHEXT (observed as '.CPL' only). Since child shells are spawned with { ...process.env }, that value propagated into every shell, stripping '.EXE' and breaking resolution of git/node/python/rg and even full-path .exe invocations under PowerShell. Repair PATHEXT on win32 just before spawn: if '.EXE' is missing, merge the standard list with whatever was present (non-destructive otherwise). Reproduces on x64 too, not only ARM64. Refs #481

…module) @vscode/ripgrep 1.18.0+ ships package.json with 'type: module'. The MCPB build copies scripts/ripgrep-wrapper.js over the package's lib/index.js, but it was CommonJS (require/module.exports), so it threw 'require is not defined in ES module scope' on import. That throw was swallowed by getRipgrepPath()'s try/catch and surfaced as a misleading 'ripgrep binary not found', silently breaking search on Windows despite the bundled binaries being present. Rewrite the wrapper as ESM (import + export const rgPath, __dirname via fileURLToPath). Refs #481

coderabbitai · 2026-05-31T13:23:02Z

No actionable comments were generated in the recent review. 🎉

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Run ID: daf362cd-4057-493e-bc43-42103968dd9b

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Reviewing files that changed from the base of the PR and between 9c44119 and 9ad0bca.

📒 Files selected for processing (2)

scripts/ripgrep-wrapper.js
src/terminal-manager.ts

📝 Walkthrough

Walkthrough

This PR migrates the ripgrep wrapper from CommonJS to ES modules with improved binary resolution fallback logic, and adds Windows-specific PATHEXT environment variable repair to prevent command resolution failures in spawned shell processes when the inherited PATHEXT is corrupted.

Changes

Windows Command Execution Reliability

Layer / File(s)	Summary
ESM migration and ripgrep binary resolution `scripts/ripgrep-wrapper.js`	Converts from CommonJS `require/module.exports` to ESM `import/export`. Derives `__dirname` via `fileURLToPath(import.meta.url)`. Refactors binary path resolution to check platform-specific binary first (`rg-[platform]`), fall back to generic `rg`/`rg.exe`, and throw a descriptive error if neither exists. Preserves Unix `chmodSync(0o755)` behavior to ensure executable permissions.
Windows PATHEXT environment repair `src/terminal-manager.ts`	Adds a standard PATHEXT constant and a helper function that detects missing `.EXE` extension in inherited PATHEXT and merges it with the standard list while preserving extras. Applies the repaired PATHEXT to `spawnOptions.env` on Windows before spawning child processes to prevent command resolution failures.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related issues

#481: Windows PATHEXT corruption in spawned processes directly addressed by terminal-manager PATHEXT repair logic.
#480: PATHEXT inheritance problem directly resolved by the new Windows environment variable repair helper.

Possibly related PRs

wonderwhy-er/DesktopCommanderMCP#262: Both modify scripts/ripgrep-wrapper.js ripgrep binary resolution and export (retrieved uses CJS, main refactors to ESM).
wonderwhy-er/DesktopCommanderMCP#401: Both modify Windows child_process.spawn options in src/terminal-manager.ts before spawning.
wonderwhy-er/DesktopCommanderMCP#270: Both modify src/terminal-manager.ts process-spawning and command execution paths.

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Suggested reviewers

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Poem

🐰 A ripgrep wrapper dons new ESM clothes,
While PATHEXT healers mend Windows woes,
Platform binaries fallback with care,
Spawned shells breathe clean Unix air,
Commands resolve without despair! 🎯

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the two main changes: fixing PATHEXT on Windows and converting the ripgrep wrapper to ESM, matching the core objectives.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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Commit on current branch

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Create PR with unit tests
Commit unit tests in branch fix/windows-support

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wonderwhy-er added 2 commits May 31, 2026 16:21

edgarsskore approved these changes Jun 1, 2026

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wonderwhy-er merged commit 673111c into main Jun 1, 2026
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coderabbitai Bot mentioned this pull request Jun 5, 2026

fix(windows): preserve quotes in cmd commands (start_process) #495

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fix(windows): repair PATHEXT in spawned shells + ESM ripgrep wrapper#484

fix(windows): repair PATHEXT in spawned shells + ESM ripgrep wrapper#484
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wonderwhy-er commented May 31, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

1. Repair corrupted PATHEXT before spawning shells (the #481 report)

2. Make the bundled ripgrep wrapper ESM

Testing

Notes

Summary by CodeRabbit

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wonderwhy-er commented May 31, 2026 •

edited by coderabbitai Bot

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1. Repair corrupted `PATHEXT` before spawning shells (the #481 report)

coderabbitai Bot commented May 31, 2026 •

edited

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