fix(daemon): keep gateway up when --mount fails

[karawitan]

What

Fixes #8977.

When ipfs daemon --mount was requested but the FUSE mount failed (missing or unusable mount points, no FUSE support, permission errors, etc.), the daemon aborted before reaching serveHTTPGateway, so the node silently stopped acting as a gateway. The startup output did not even mention the gateway.

Why

The startup sequence in cmd/ipfs/kubo/daemon.go ordered the FUSE mount (mountFuse) before serveHTTPGateway:

if mount {
    if err := mountFuse(req, cctx); err != nil {
        return err          // <-- daemon exits here
    }
    ...
}
...
gwErrc, err := serveHTTPGateway(req, cctx)   // <-- never reached

A FUSE mount is an optional, experimental feature. Its failure should not take down the HTTP gateway the operator asked the daemon to serve, nor the rest of the daemon (GC, libp2p gateway, metrics, MFS pinning).

Change

When mountFuse fails, print a warning to stderr and via the log, then continue without FUSE mounts so the rest of the daemon — including the HTTP gateway — starts normally. The unmount cleanup defer only runs when the mount actually succeeded.

This is a bug fix for the kind/bug/help wanted issue #8977; it does not touch the /api/v0/ RPC API, the HTTP gateway contract, the CID recipe, or any wire behavior.

Verification

• go build ./cmd/ipfs/ and go vet ./cmd/ipfs/ ./test/cli/ pass.
• New regression test TestDaemonGatewayUpWhenMountFails in test/cli/daemon_mount_test.go:
  • starts the daemon with --mount and non-existent mount paths (forces mountFuse to fail at checkFusePath, no FUSE support needed on the host),
  • asserts the gateway still serves content (GET /ipfs/<cid> → 200),
  • asserts the mount failure is reported on stderr and nothing was silently mounted.
• Test passes locally.

=== RUN   TestDaemonGatewayUpWhenMountFails
--- PASS: TestDaemonGatewayUpWhenMountFails (2.87s)
    --- PASS: TestDaemonGatewayUpWhenMountFails/gateway_still_serves_content (0.00s)
    --- PASS: TestDaemonGatewayUpWhenMountFails/mount_failure_was_reported_on_stderr (0.00s)
PASS

Changelog

Added a highlight to docs/changelogs/v0.44.md.

Generated with Devin