DMC worktree add returns PHP-WASM ErrnoError after creating worktree

[chubes4]

Summary

studio wp datamachine-code workspace worktree add can create the requested worktree, then exit non-zero with a PHP-WASM ErrnoError 33 from the Studio runtime.

Observed while fixing wp-site-generator bench blocker

Commands attempted from /Users/chubes/Studio/intelligence-chubes4:

studio wp datamachine-code workspace worktree add wp-codebox fix/bench-wp-cli-ssi-workload --base-branch=main --task-url=https://github.com/chubes4/wp-site-generator/issues/368 --task-ref=chubes4/wp-site-generator#368

studio wp datamachine-code workspace worktree add wp-site-generator verify/ssi-bench-workload --from=origin/static/issue-367-kiln-ledger --skip-bootstrap --task-url=https://github.com/chubes4/wp-site-generator/pull/373 --task-ref=chubes4/wp-site-generator#373

studio wp datamachine-code workspace worktree add static-site-importer fix/asset-policy-default --base-branch=main --skip-bootstrap --task-url=https://github.com/chubes4/wp-site-generator/issues/368 --task-ref=chubes4/wp-site-generator#368

All returned:

file:///Users/chubes/Developer/studio/node_modules/@php-wasm/node-8-3/jspi/php_8_3.js:2955
    throw new FS.ErrnoError(33);
    ^
ErrnoError { name: 'ErrnoError', errno: 33 }

Node.js v24.13.1

In each case the worktree directory existed afterward and was usable. Example: /Users/chubes/Developer/static-site-importer@fix-asset-policy-default.

Expected

If worktree creation succeeds, the command should exit 0 or clearly report a bounded post-create/bootstrap failure while preserving the created worktree metadata.

Impact

Agents see a failed DMC worktree command even though the worktree exists, which encourages unsafe raw-git fallback or duplicate worktree creation.

[chubes4]

Fresh reproduction from Homeboy issue worktree creation:

• Command: studio wp datamachine-code workspace worktree add homeboy fix/issue-3264-deploy-plan --task-url=https://github.com/Extra-Chill/homeboy/issues/3264 --task-ref=Extra-Chill/homeboy#3264
• First attempt returned a structured busy error: Workspace repo "homeboy" is busy with another worktree lifecycle mutation.
• Retry after 10s crashed in PHP-WASM/Node result handling:

file:///Users/chubes/Developer/studio/node_modules/@php-wasm/node-8-3/jspi/php_8_3.js:2955
    throw new FS.ErrnoError(33);
    ^
ErrnoError { name: 'ErrnoError', errno: 33 }

Node.js v24.13.1

• The worktree was still created successfully at /Users/chubes/Developer/homeboy@fix-issue-3264-deploy-plan.
• Inside that worktree, git status --short --branch reports: ## fix/issue-3264-deploy-plan...origin/main.

This looks like a DMC/Studio/PHP-WASM result-reporting crash after the mutating operation succeeds, not a failure to create the worktree. Chris noted there is an open upstream WordPress Playground PR that may be related; the investigation should check whether this matches that upstream failure mode before patching around it in DMC.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Capturing reproduction evidence from a live DMC worktree-add failure.