Graph Filesystem File Interactions

fs:<path> is the generic filesystem path adapter. Directory paths render the existing searchable directory listing and opening an entry materializes a child fs:<child-path> node with an explicit edge.

Regular file paths render a SearchView of explicit interaction rows. Interaction rows are data objects with kind fields; labels are display text only.

File type detection is conservative and extension-based for this iteration. Viewer and module rows are emitted only for regular files classified as known text/source extensions; unknown regular files expose only the safe :external-editor interaction.

File interactions

• :external-editor opens ExternalEditor.open-file(path, callback) and does not add graph topology.
• :file-viewer materializes fs-file-viewer:<absolute-path> and adds an explicit edge from the file FsNode.
• :module materializes fnl-module:<absolute-path>, cpp-module:<absolute-path>, or text-module:<absolute-path> and adds an explicit edge.

Editable lazy internal viewer

fs-file-viewer:<absolute-path> is a UX-purpose graph node backed by LazyTextSource.file, LazyTextBuffer, and the VirtualInput widget. It opens regular text/source files as editable lazy text without loading the whole file into memory and without serializing file contents into graph state.

The viewer UI uses VirtualInput for internal editing. Input and InputModel remain for small in-memory controls and must not be used for file-scale text. VirtualInput renders only visible rows from bounded viewport snapshots and routes edits to the lazy piece-table buffer.

The viewer provides explicit Save and Edit externally controls. The external-editor button remains available because double-click behavior is not the primary file-opening affordance for this lazy editable viewer.

Saving follows a pragmatic Neovim/Vim-style contract: the viewer does not blindly overwrite known stale external changes, and detected conflicts leave the user's in-memory edits dirty. Before saving, the viewer checks whether the file token still matches the buffer baseline; the buffer then saves through fs.atomic-replace-if-current, which revalidates the token after writing the temporary replacement and immediately before rename. POSIX/Linux cannot prevent a non-cooperating writer from changing the path in the tiny gap between final validation and rename, so this is normal stale-change detection rather than strict race-free CAS.

Persistence invariant

Graph persistence stores visible node keys and explicit edge keys only. File content remains owned by the filesystem and is never captured in graph topology state.