Release: auto-switch profiles for cross-profile session links (#5419)

[nesquena-hermes]

Release: auto-switch profiles for cross-profile session links (#5419)

A valid session:// deep link to a session owned by a different Hermes profile used to look identical to a deleted session (404 → the frontend self-healed away, "Session not available in web UI"). Now GET /api/session returns a structured 409 session_profile_mismatch envelope (error/code/session_id/profile ONLY — no transcript) when the owning profile is known, and loadSession() switches to the owning profile and retries once. Truly missing/deleted (or legacy None-profile) sessions keep the 404 self-heal.

Source PR: #5419 by @harcek. Diff: +226 (api/routes.py, static/sessions.js, tests).

Maintainer changes + gate fixes (Codex + Fable)

• Codex CORE: added a post-await stale-load guard after _switchProfileForSessionLoad so a navigation during the profile switch (POST + list re-render) can't hijack the UI back to the old session.
• Fable Finding 1 (moderate-high, reproduced): only emit the 409 when _session_profile is truthy. _profiles_match coerces None→'default', so a truly-missing/legacy None-profile session under a non-default active profile would otherwise emit a useless profile:null 409 — the frontend requires a truthy profile, so it fell into the generic error branch, skipped the 404 self-heal, and re-armed the SSE stream against a dead session id. Fixed on both detail branches + 2 mutation-checked regression tests.
• Fable Finding 2 (moderate): _switchProfileForSessionLoad now clears the sidebar skeleton + re-renders from cache on switch-POST failure (mirrors the Profile switch: polished loading skeletons (sidebar + workspace) — #4662 phase 1 #4671 canonical-switch catch), then rethrows — a failed switch no longer strands the sidebar on the skeleton.
• Reconciled the 4 test_issue1611 profile-isolation tests to the 409 contract while preserving the no-leak boundary assertion (envelope-key allowlist + explicit forbidden-key checks).

Gate (all green)

• Codex: SAFE after the stale-load fix (no transcript leak, exemption safe — both detail branches re-check, no infinite loop).
• Fable: the 2 findings above fixed; re-verified everything else clean. Info-disclosure delta (session-existence oracle + owning-profile-name) judged acceptable for the single-user/multi-profile model (profile names already enumerable via /api/profiles); Finding-1 fix narrows it further.
• Full suite: clean (39/39 isolation+sweep tests via prod venv; the 1 TLS failure in the stage worktree is the known worktree-.venv-missing-deps artifact — passes with deps, fix: auto-switch profiles for session links #5419 touches no TLS code).

Attribution preserved: authored as @harcek + maintainer Co-authored-by. CHANGELOG credit.

[greptile-apps]

Greptile Summary

This PR teaches session deep links how to recover across profiles. The main changes are:

• /api/session can return a structured profile-mismatch response.
• The session loader can switch profiles and retry the load once.
• Missing or unknown-profile sessions keep the old 404 self-heal path.
• Profile-isolation tests now cover the new envelope shape.

Confidence Score: 4/5

The cross-profile CLI session path needs a fix before merging.

• The main web-session mismatch path returns a small terminal envelope before content is returned.
• The frontend retry path has guards for stale navigation during the profile switch.
• The CLI fallback can still return 404 for a valid foreign-profile CLI session because its owner lookup stays scoped to the active profile.

api/routes.py

Important Files Changed

Filename	Overview
api/routes.py	Adds route-local profile-mismatch handling for /api/session; the CLI fallback can still miss foreign-profile ownership metadata.
static/sessions.js	Adds mismatch parsing, profile switching, stale-load guards, and retry-once behavior for session loads.
tests/test_issue1611_session_profile_filtering.py	Updates profile-isolation tests for the 409 envelope and keeps coverage for unknown-profile 404 behavior.
tests/test_bugfix_sweep.py	Adds a smoke test for the cross-profile deep-link flow.
CHANGELOG.md	Documents the release-visible session-link behavior change.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
  participant UI as loadSession()
  participant API as GET /api/session
  participant Switch as POST /api/profile/switch
  UI->>API: Load session under active profile
  API-->>UI: 409 session_profile_mismatch(profile)
  UI->>Switch: Switch to owning profile
  Switch-->>UI: New active profile
  UI->>API: Retry session load once
  API-->>UI: Session data or normal error

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
  participant UI as loadSession()
  participant API as GET /api/session
  participant Switch as POST /api/profile/switch
  UI->>API: Load session under active profile
  API-->>UI: 409 session_profile_mismatch(profile)
  UI->>Switch: Switch to owning profile
  Switch-->>UI: New active profile
  UI->>API: Retry session load once
  API-->>UI: Session data or normal error

Loading

_{Reviews (1): Last reviewed commit: "fix: auto-switch profiles for session li..." | Re-trigger Greptile}

[greptile-apps]

CLI Owner Lookup Stays Scoped

When a session:// link points to a CLI session owned by another profile, this lookup still uses the active-profile-only default, so it returns no metadata and _session_profile becomes None. That sends the request down the 404 self-heal path instead of the new session_profile_mismatch response, so valid cross-profile CLI links are still treated as deleted sessions.

[cutter-sh]

🎬 Cutter preview — PR #5728

Open cross-profile session deep link — Opening a cross-profile session link auto-switches to that session's profile with a notification.