fix: work in flight hangs after the app is suspended in the background

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
dart, flutter, ios
Domain
mobile

Research direction

Start with SSHKeepAlive.ping() in packages/dartssh2/lib/src/ssh_keepalive.dart: add a timeout and close the client on failure so later pings still run. Then bound the cancel paths — collectSshExecOutput in lib/core/utils/ssh_exec.dart (await commandDone) and _terminateAiCommandSession in lib/view/page/ssh/page/ask_ai.dart. In fl_pi_llm's runtime.dart add a stream stall watchdog and a resume check; wrap in-flight iOS runs in beginBackgroundTask. Done when a connection killed during suspension ends within the short wait instead of hanging.

Written by the indexing model from the issue text.

Description

bug

A run or connection that is in flight when the app is suspended in the background can hang after resume, and nothing ends it.

SSH
  • SSHKeepAlive (packages/dartssh2/lib/src/ssh_keepalive.dart): ping() has no timeout and a failure never closes the client. One unanswered ping stops every later keepalive, so a silently dead connection (NAT/server dropped it while suspended) is never detected.
  • Cancel paths wait on session.done with no limit: collectSshExecOutput (lib/core/utils/ssh_exec.dart, await commandDone) and _terminateAiCommandSession (lib/view/page/ssh/page/ask_ai.dart). On a dead connection neither the 5-minute tool timeout nor Stop ends an Agent tool call. Fall back to closing the channel/client after a short wait.
  • ServerNotifier keeps a client whose status read timed out and marks it connected; ensureShellClient/ensureExec reuse it. Nothing checks state.client on resume (terminal tabs reconnect, but they own separate clients).
Agent (fl_pi_llm)
  • LLM HTTP streams have no stall timeout (runtime.dart, default HttpClient, body read with no watchdog).
  • No lifecycle handling: a run suspended mid-request or mid-tool is not checked on resume.
iOS
  • No beginBackgroundTask around an in-flight transfer. UIBackgroundModes declares fetch with no handler (removed).
  • No beginBackgroundTask around an in-flight Agent run: needs fl_pi_llm to say whether any chat is running (InFlightWork TODO).

Related: a run cut off by the process being killed was left holding its session ("Lane "main" already has an active operation"); fixed in fl_pi_llm. Android Agent runs keep the foreground service up in a separate change.

Done in #1705 (lollipopkit/dartssh2#26). The rest is fl_pi_llm.

Dominant language
Dart
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Merged PRs (30d)
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