vfs: add a composite merged-filesystem implementation #83

New Issue

2026-07-12T02:17:44+02:00

codinget commented

2026-07-12 02:17:44 +02:00

Motivation

Applications increasingly need to present several AsyncVFS backends through one namespace—for example memory/OPFS content, Taildrop, WebDAV, FTP, SFTP, and SMB shares. Without a package-owned composite, each application must implement path routing, synthetic directory entries, cross-backend operations, capability negotiation, and error handling itself.

Requested direction

Add a composite or merged AsyncVFS implementation to @webnet/vfs.

The initial design should explicitly choose and document its namespace model. A mount-table model is the safest baseline:

mount independent VFS instances at normalized paths;
expose synthetic ancestor directories and merge their entries with backend entries;
route operations to the longest matching mount;
prevent .. and normalization from escaping or bypassing a mount;
support dynamic or immutable mount configuration.

If overlay semantics—multiple backends at the same path with precedence and copy-up—are desired, treat those as an explicit additional policy rather than an accidental consequence of iteration order.

Operations and capabilities

Specify:

stat/readdir behavior at root, synthetic ancestors, mount points, and collisions;
same-backend versus cross-backend copy/move;
whether cross-backend operations use the standard shims;
write routing and read-only mounts;
propagation of optional capabilities and runtime unimplemented errors;
mount lifecycle, backend shutdown, and failures from one backend;
stable path/name rewriting in returned Stat values;
behavior when a mount disappears during an open stream.

Use the canonical path utilities tracked in #78 and the optional-operation/error model tracked in the companion VFS issue. Add composite-specific tests plus the common AsyncVFS conformance suite from #80.

This is a larger follow-up and should start only after the current filesystem protocol PRs have merged.

## Motivation Applications increasingly need to present several `AsyncVFS` backends through one namespace—for example memory/OPFS content, Taildrop, WebDAV, FTP, SFTP, and SMB shares. Without a package-owned composite, each application must implement path routing, synthetic directory entries, cross-backend operations, capability negotiation, and error handling itself. ## Requested direction Add a composite or merged `AsyncVFS` implementation to `@webnet/vfs`. The initial design should explicitly choose and document its namespace model. A mount-table model is the safest baseline: - mount independent VFS instances at normalized paths; - expose synthetic ancestor directories and merge their entries with backend entries; - route operations to the longest matching mount; - prevent `..` and normalization from escaping or bypassing a mount; - support dynamic or immutable mount configuration. If overlay semantics—multiple backends at the same path with precedence and copy-up—are desired, treat those as an explicit additional policy rather than an accidental consequence of iteration order. ## Operations and capabilities Specify: - stat/readdir behavior at root, synthetic ancestors, mount points, and collisions; - same-backend versus cross-backend copy/move; - whether cross-backend operations use the standard shims; - write routing and read-only mounts; - propagation of optional capabilities and runtime `unimplemented` errors; - mount lifecycle, backend shutdown, and failures from one backend; - stable path/name rewriting in returned `Stat` values; - behavior when a mount disappears during an open stream. Use the canonical path utilities tracked in #78 and the optional-operation/error model tracked in the companion VFS issue. Add composite-specific tests plus the common `AsyncVFS` conformance suite from #80. This is a larger follow-up and should start only after the current filesystem protocol PRs have merged.

codinget referenced this issue

2026-07-12 02:46:53 +02:00

tailshare: copy and move files between sources #87

codinget referenced this issue

2026-07-12 02:46:54 +02:00

tailshare: serve VFS content over WebDAV to Tailnet, Funnel, and Taildrive #90

codinget added this to the Tailshare roadmap project 2026-07-12 03:05:49 +02:00

codinget moved this to Blocked in Tailshare roadmap on 2026-07-12 03:07:21 +02:00

codinget added the

Agent

gpt-5.6-sol

4