Filesystem Footprint 📂

Every host-filesystem location the editor reads or writes, mapped to its producing code, with cross-platform resolution and cleanup recipes.

macOS Linux Windows

Why This Document Exists 🎯

Both Land (Tauri shell + workbench wiring) and the bundled VS Code dependency are ours to modify. That means today’s filesystem layout is incidental rather than required - the doc enumerates what we touch so future work on cleanup, versioning, packaging, and encapsulation has a single source of truth to start from. The minimum-effect-over-the-system goal demands knowing exactly where the side effects are.

The Four Ownership Domains 🗺️

Three observations follow from this split and inform every sub-document:

• The bundled VS Code expects a per-instance app_data_dir-style root (settings, keybindings, profiles). Tauri’s PathResolver resolves it per-OS - so one tree per build profile, OS-specific leaf.
• Land’s own product state lives under ~/.fiddee/ (cross-OS), shared across every build profile of the editor a user runs.
• The webview half writes through the OS-native webview, so its persisted state lands in OS-controlled directories. Land cannot rename those locations but can configure what the webview writes into them.

The Bundle-Identifier Story 🆔

The Tauri identifier is the leaf segment of every per-bundle path. Today’s identifiers encode each Maintain build profile’s full configuration matrix into a single string:

Source of truth: Element/Mountain/tauri.conf.json (per-profile via Maintain templating).

Two consequences:

• A user who runs both debug and release accumulates two parallel per-bundle trees - one tree of caches and logs per profile.
• Mountain’s IPC/DevLog/AppDataPrefix.rs::DetectAppDataPrefix does a runtime read_dir of the OS <app_data_dir> looking for the directory whose name starts with land.editor. and contains mountain. The match returns its own bundle identifier - so when DevLog needs to write a session log, it discovers the path rather than hard-coding it. This is what makes the editor robust against identifier changes from Maintain regenerating tauri.conf.json.

A shorter, stable bundle identifier (e.g. cloud.fiddee.editor or editor.fiddee.binary) would fold all profile-specific differences into a per-profile subdirectory and make uninstall a one-line rm -rf. Not done today.

Document Index 📑

The footprint splits across six focused documents. Read in order for a full tour, or jump to whichever matches the task at hand.

Cross-Cutting Observations 🔍

• Three log destinations. Mountain session logs land in <app_data_dir>/<bundle>/logs/<ts>/Mountain.dev.log; workbench logs live in <app_data_dir>/<bundle>/logs/window1/output_*; per-extension logs in ~/.fiddee/logs/<extId>/. No central rotation, no max-size enforcement. Trace=all debug sessions of ~200 MB compound quickly.
• Two userdata bases per profile. <app_data_dir>/<bundle>/ (Tauri, per-profile, holds machine-id + workbench userdata) coexists with ~/.fiddee/ (product, shared across profiles, holds extensions + per-extension storage). “Wipe the app’s state” requires touching both plus four OS-managed locations.
• Two extension roots. ~/.fiddee/extensions/ (primary) and ~/.land/extensions/ (legacy). Both scanned; only the former is written.
• Two FIDDEE roots. Mountain owns ~/.fiddee/ (dotfile, lowercase). The Air background daemon writes to <config_dir>/FIDDEE/ (uppercase, under the OS config root). Different conventions; same product. Reconciliation is a Branch H encapsulation candidate.
• Two install identifiers. <app_data_dir>/<bundle>/machine-id.txt (Mountain UUID) is separate from the PostHog distinctId (Sky-side, lives in webview localStorage). Analytics see two identities per install.
• Backup files accumulate. Memento corruption recovery writes <state>.json.backup and <state>.json.corrupted.<YYYYMMDD_HHMMSS> siblings but never prunes them.
• Temp-dir leakage. <tmp>/land-zsh-integration-<pid>/ accumulates (one per integrated-terminal launch); <tmp>/vine_fallback.proto is overwritten but never removed.
• Cocoon writes inside the extension bundle dir (~/.fiddee/extensions/<id>/.storage/). Removing or version-bumping an extension destroys that state - subtle, since Land’s three other storage paths (extensionStorage, globalStorage, logs) live outside the bundle and would survive a reinstall.
• Bundle identifier explosion. Each Maintain profile produces its own per-bundle tree. A developer running debug, release, and a browser variant accumulates three full sets.

Related Documentation 📚

• Environment Variables - the canonical environment-variable registry. Cross-referenced from the Environment Variables sub-document.
• Building - Maintain build profiles and how they produce the bundle identifiers enumerated above.
• Build Matrix - the matrix of (profile, target, level) combinations that map to bundle identifier suffixes.
• Application Startup and Handshake
  • the boot sequence inside which AppLifecycle::Dirs runs.

Key source files 🦴

Update this index and the relevant sub-document when adding any new path, renaming a leaf, or retiring a location.