fix(tools): prevent worker deadlock when agent backgrounds server via shell & (#68915) - #70549
Closed
webtecnica wants to merge 1 commit into
Closed
webtecnica wants to merge 1 commit into
webtecnica wants to merge 1 commit into
Conversation
…ker deadlock on server backgrounding Issue NousResearch#68915: when the agent runs a compound command with trailing & (e.g. `cd /app && node server.js &`), bash parses it as `(A && B) &` — a subshell that holds the stdout pipe open forever when B is a long-running server. The existing _rewrite_compound_background in terminal_tool.py correctly rewrites this to `A && { B & }` to avoid the subshell fork, but it was only applied in the foreground execute() path (tools/environments/base.py). The background spawn_local() path bypasses base.py entirely and passed the raw command directly to Popen/PTY, leaving the deadlock unmitigated. Fix: apply _rewrite_compound_background in spawn_local() before the command is passed to Popen or PTY spawn. Uses a lazy import to avoid circular dependency (terminal_tool imports process_registry). - PTY spawn path: now uses safe_command (rewritten) - Popen spawn path: now uses safe_command (rewritten) - Session.command still stores the original (unrewritten) command for display - Simple `cmd &` is left unchanged (no subshell bug) Tests: 4 regression tests verifying (1) compound is rewritten, (2) simple bg is preserved, (3) multi-line compounds are rewritten, (4) session.command stores original.
alt-glitch
added
type/bug
Contributor
|
Closing as duplicate of #70884 (salvage of #70546). Both your spawn_local fix and the telegram connect fix were salvaged together. Your authorship preserved via cherry-pick. Note: the commits in #70546 were authored under "Hermes Agent" identity — added contributor email mapping (agent@hermes.dev -> webtecnica) in the salvage PR. |
kshitijk4poor
added a commit
to kshitijk4poor/hermes-agent
that referenced
this pull request
Jul 24, 2026
Follow-up to salvaged PR NousResearch#70549: - Replace fragile 'or' assertions with single precise checks that catch partial-rewrite regressions (would have masked a missing closing brace) - Add test_pty_path_uses_rewritten_command covering the PTY spawn path that was modified but previously untested
kshitijk4poor
added a commit
that referenced
this pull request
Jul 24, 2026
Follow-up to salvaged PR #70549: - Replace fragile 'or' assertions with single precise checks that catch partial-rewrite regressions (would have masked a missing closing brace) - Add test_pty_path_uses_rewritten_command covering the PTY spawn path that was modified but previously untested
Contributor
|
Merged via #70876 — your fix was cherry-picked with authorship preserved, and the original fix landed on main (commit d7512c8). Your PR identified that Thanks for the contribution! |
randlee
pushed a commit
to randlee/hermes-agent
that referenced
this pull request
Aug 11, 2026
Follow-up to salvaged PR NousResearch#70549: - Replace fragile 'or' assertions with single precise checks that catch partial-rewrite regressions (would have masked a missing closing brace) - Add test_pty_path_uses_rewritten_command covering the PTY spawn path that was modified but previously untested
prmartinow
pushed a commit
to prmartinow/hermes-agent
that referenced
this pull request
Aug 26, 2026
Follow-up to salvaged PR NousResearch#70549: - Replace fragile 'or' assertions with single precise checks that catch partial-rewrite regressions (would have masked a missing closing brace) - Add test_pty_path_uses_rewritten_command covering the PTY spawn path that was modified but previously untested
melon-xf
added a commit
to melon-xf/hermes-agent
that referenced
this pull request
Sep 3, 2026
Follow-up to salvaged PR NousResearch#70549: - Replace fragile 'or' assertions with single precise checks that catch partial-rewrite regressions (would have masked a missing closing brace) - Add test_pty_path_uses_rewritten_command covering the PTY spawn path that was modified but previously untested
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Problem
When LLM issues
A && B &via terminal, bash creates a subshell that holds stdout pipe open → worker deadlocks permanently (requires kill -9).Root Cause
The existing
_rewrite_compound_backgroundfix only ran in the foreground path (base.py:execute()). The backgroundspawn_local()path inprocess_registry.pybypassed it entirely.Fix
_rewrite_compound_backgroundcall inspawn_local()before Popen/PTY spawncmd &(without &&) preserved unchangedFixes #68915