Vercel: use /tmp for data dir

[gitgrahamdunn]

Motivation

• Prevent import-time OSError: [Errno 30] Read-only file system on serverless platforms (Vercel) by avoiding creating directories inside the deployed code folder.
• Preserve existing override via the DATA_DIR env var while defaulting to a writable location when not provided.

Description

• Add _ensure_writable_data_dir(path: Path) to attempt mkdir and fall back to "/tmp/gitplant-data" on OSError during import-time initialization.
• Use _default_data_dir() (which still honors DATA_DIR and prefixes relative paths with /tmp) together with the new helper to set DEFAULT_DATA_DIR.
• Move default DEFAULT_STORAGE_DIR and DEFAULT_PLANT_STORAGE_DIR to live under the resolved DEFAULT_DATA_DIR instead of the repository storage folder.
• Do not change route or business logic; only change default storage path resolution and make directory creation resilient.

Testing

• Ran python -m compileall backend/app/config.py which completed successfully.
• Performed an import smoke check with python - <<'PY' ... from backend.app.config import DEFAULT_DATA_DIR, DEFAULT_STORAGE_DIR, DEFAULT_PLANT_STORAGE_DIR ... PY which printed the resolved /tmp-based paths and succeeded.

---

Codex Task

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
gitplant	Ready	Preview, Comment	Feb 18, 2026 10:13pm
gitplant-backend	Ready	Preview, Comment	Feb 18, 2026 10:13pm
gitplant-oggy	Ready	Preview, Comment	Feb 18, 2026 10:13pm

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: d9839f9b67

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Don't ignore configured DATA_DIR on mkdir errors

If DATA_DIR is explicitly set but path.mkdir(...) fails (for example, the target is a file path or a mounted volume is not writable at startup), this branch silently falls back to /tmp/gitplant-data and continues. That causes the app to write DB/files to ephemeral storage while operators believe the configured persistent path is in use, which can lead to apparent data loss after restarts. Consider failing fast (or at least surfacing an error) when a user-provided DATA_DIR cannot be created, and reserve fallback for implicit defaults.

Useful? React with 👍 / 👎.