Server(fix[new_session]): Harden error handling and TMUX env restoration#628
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Server(fix[new_session]): Harden error handling and TMUX env restoration#628
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #628 +/- ##
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+ Coverage 46.58% 46.90% +0.32%
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Files 22 22
Lines 2372 2375 +3
Branches 390 391 +1
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+ Hits 1105 1114 +9
+ Misses 1098 1093 -5
+ Partials 169 168 -1 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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… empty why: Server.new_session reads session_stdout via proc.stdout[0] without checking that proc.stdout has any elements. If tmux returns empty stdout (without writing to stderr — corrupt pipe, kernel-level signal mid-write, mocked transport), this raises an unhelpful IndexError instead of a branded LibTmuxException. The TMUX env restoration was already wrapped in try/finally on master, but the empty-stdout guard was missing. what: - add 'if not proc.stdout: raise LibTmuxException' check before indexing proc.stdout[0] - add tests for empty stdout, TMUX env restoration on cmd-side errors, and TMUX env restoration on setup-phase errors (to verify the existing try/finally covers arg-building, not just the cmd() call) - tests use monkeypatch per CLAUDE.md (cannot trigger empty stdout from a healthy tmux server otherwise)
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Summary
new_session()deletesos.environ["TMUX"]before calling tmux but only restores it on the success path — any exception permanently leaks the deletion. This wraps all post-deletion code intry/finally.proc.stdout[0]raises an unhelpfulIndexErrorif tmux produces no output. This adds an explicit guard with a descriptiveLibTmuxException.Split out from #576 — hardening that's independent of the race condition fix itself.
Changes
src/libtmux/server.py:del os.environ["TMUX"]intry/finallyto ensure restoration on any exception (including setup-phase errors likepathlib.Path.expanduser())proc.stdoutwith descriptiveLibTmuxExceptiontests/test_server.py:test_new_session_empty_stdout— verifies error on empty stdouttest_new_session_restores_tmux_env_on_error— verifies TMUX restored after cmd errortest_new_session_restores_tmux_env_on_setup_error— verifies TMUX restored after setup-phase errorTest plan
uv run pytest— 875 passed, 1 skippeduv run ruff check .— all checks passeduv run mypy src tests— no issues