fix: detect Bun compiled binary when import.meta.url percent-encodes ~BUN

[gjtorikian]

Why

The v0.20.0 release failed both Windows smoke tests with:

VERIFY_ASSETS_AGENT_SDK_FAILED: Cannot find module
'@anthropic-ai/claude-agent-sdk-win32-x64/package.json' from 'B:\~BUN\root\workos-windows-x64.exe'

isCompiledBinary() checks import.meta.url for $bunfs (POSIX) or ~BUN (Windows). But Bun's URL serializer (WebKit WTF::URL::fileURLWithFileSystemPath) percent-encodes the tilde, so on Windows the URL is file:///B:/%7EBUN/root/… — neither marker matches. The compiled binary then took the dev-mode path and tried to resolve the Agent SDK from node_modules, which doesn't exist in a standalone binary.

Verified empirically (same serializer as Bun.pathToFileURL):

$ bun -e 'console.log(Bun.pathToFileURL("/tmp/~BUN/root/x.exe").href)'
file:///tmp/%7EBUN/root/x.exe

POSIX targets were unaffected because $ isn't percent-encoded, which is why all six macOS/Linux smoke tests passed.

What

• Extract the marker check into isBunVirtualFsUrl() and additionally match the percent-encoded %7EBUN form.
• Regression tests covering the exact URL shape observed in the failed Windows smoke run.

Note: Bun.isStandaloneExecutable is the official API for this, but it shipped after Bun 1.3.14 (the version CI pins), so the URL heuristic stays.

Verification

• bun run test (2033 pass), bun run typecheck, bun run build all green.
• The real gate is the release pipeline's Windows smoke jobs, which run internal verify-assets on real Windows hardware before anything publishes.

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR fixes Bun standalone-binary detection for percent-encoded Windows virtual-filesystem URLs.

• Extracts the virtual-filesystem marker check into an exported helper.
• Recognizes %7EBUN in addition to the existing POSIX and raw Windows markers.
• Adds regression coverage for compiled and source-mode URL forms.

Confidence Score: 4/5

The PR appears safe to merge, with a non-blocking path-boundary hardening opportunity in the new encoded-marker check.

The intended Windows standalone URL is now detected, but matching %7EBUN anywhere can send an unusual source checkout path through the download-and-cache branch.

Files Needing Attention: src/lib/agent-sdk-assets.ts

Important Files Changed

Filename	Overview
src/lib/agent-sdk-assets.ts	Adds encoded Windows marker detection, though the unbounded substring match can classify ordinary source paths containing ~BUN as compiled.
src/lib/agent-sdk-assets.spec.ts	Adds focused positive and negative tests for Bun virtual-filesystem URL detection.

Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
src/lib/agent-sdk-assets.ts:64
**Unbounded virtual-filesystem marker match**

The new check accepts `%7EBUN` anywhere in a source-mode module URL, so an ordinary path containing a `~BUN` component is classified as compiled and unnecessarily enters the download-and-cache flow instead of resolving the installed node_modules asset. Match the documented virtual-filesystem segment, such as `%7EBUN/root/`, to avoid breaking offline use from such paths.

_{Reviews (1): Last reviewed commit: "fix: detect Bun compiled binary when imp..." | Re-trigger Greptile}

[greptile-apps]

Unbounded virtual-filesystem marker match

The new check accepts %7EBUN anywhere in a source-mode module URL, so an ordinary path containing a ~BUN component is classified as compiled and unnecessarily enters the download-and-cache flow instead of resolving the installed node_modules asset. Match the documented virtual-filesystem segment, such as %7EBUN/root/, to avoid breaking offline use from such paths.

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/lib/agent-sdk-assets.ts
Line: 64

Comment:
**Unbounded virtual-filesystem marker match**

The new check accepts `%7EBUN` anywhere in a source-mode module URL, so an ordinary path containing a `~BUN` component is classified as compiled and unnecessarily enters the download-and-cache flow instead of resolving the installed node_modules asset. Match the documented virtual-filesystem segment, such as `%7EBUN/root/`, to avoid breaking offline use from such paths.

How can I resolve this? If you propose a fix, please make it concise.