fix(FR-3015): gate app-launch session-not-found message to managers below 26.4.4

[nowgnuesLee]

Resolves #7662 (FR-3015)

Summary

Follow-up to #7409 (FR-2586). That PR added a friendly "session not accessible" message when an app launch fails with a 404 / "session not found" — the common cause being an access-key (AK) mismatch, where the session was created under a different keypair than the one currently in use.

From manager 26.4.4 on, streaming session lookups are scoped by the owner's user id instead of the access key. A user's sessions are therefore reachable across all of their keypairs, so the AK-mismatch case the FR-2586 workaround targets no longer occurs on those managers. This PR version-gates the workaround so it only applies to managers below 26.4.4.

Implementation

• packages/backend.ai-client/src/client.ts: register a new capability flag session-app-by-user-uuid, enabled for managers >= 26.4.4 in _updateSupportList().

• react/src/hooks/useBackendAIAppLauncher.tsx: gate the FR-2586 friendly AppLaunchError behind both conditions — the error is a session-not-found error and the manager lacks session-app-by-user-uuid:

  if (
    isSessionNotFoundError(err) &&
    !baiClient.supports('session-app-by-user-uuid')
  ) {
    // friendly "SessionNotAccessible" message (pre-26.4.4 only)
  }

  On 26.4.4+ the workaround is disabled and the original manager error surfaces unchanged.

Behavior matrix

Manager	Error	Before this PR	After this PR
< 26.4.4	404 session-not-found (AK mismatch)	friendly message	friendly message
< 26.4.4	non-404 (proxy down, timeout)	raw error	raw error
26.4.4+	404 session-not-found (genuinely gone)	friendly message	raw error
26.4.4+	non-404	raw error	raw error

Test Plan

• Pre-26.4.4 manager: launch an app on a session created under a different AK → friendly "SessionNotAccessible" message appears.
• Pre-26.4.4 manager: trigger a non-404 launch failure (e.g. proxy down) → original error message, not the AK-mismatch message.
• 26.4.4+ manager: a session is reachable across the user's keypairs; if a launch 404s for an unrelated reason, the raw manager error surfaces (no AK-mismatch message).
• Normal session launch on any manager → no behavior change.

Verification

bash scripts/verify.sh — Relay / Lint / Format / TypeScript all PASS. (The "Vite warmup paths" check fails on a clean checkout too because it resolves production-build artifacts that are absent without pnpm build; unrelated to this change.)

Related

• fix(FR-2586): clearer error when app launch fails due to access key mismatch #7409 (FR-2586) — the original workaround this PR version-gates.

[nowgnuesLee]

• fix(FR-3015): gate app-launch session-not-found message to managers below 26.4.4 #7663 👈 (View in Graphite)
• main

---

How to use the Graphite Merge Queue

Add either label to this PR to merge it via the merge queue:

• flow:merge-queue - adds this PR to the back of the merge queue
• flow:hotfix - for urgent changes, fast-track this PR to the front of the merge queue

You must have a Graphite account in order to use the merge queue. Sign up using this link.

An organization admin has required the Graphite Merge Queue in this repository.

Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.

This stack of pull requests is managed by Graphite. Learn more about stacking.

[github-actions]

Coverage Report for react-coverage (./react)

Status	Category	Percentage	Covered / Total
🔵	Lines	6.63%	1799 / 27095
🔵	Statements	5.41%	1994 / 36805
🔵	Functions	5.38%	297 / 5514
🔵	Branches	3.78%	1300 / 34373

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
react/src/hooks/useBackendAIAppLauncher.tsx	0%	0%	0%	0%	13-1075

Generated in workflow #1261 for commit 3fab8ae by the Vitest Coverage Report Action