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dl looks for devpod's ssh config where devpod writes it #421
Description
Question
dl looks for devpod's ssh config at a hardcoded ~/.ssh/config, which devpod
never creates when DEVPOD_SSH_CONFIG is set. This is a shipped bug, not just
a prerequisite: on any host that sets that variable, dl silently loses the pty
transport and falls back, with nothing said.
Found twice independently, by
#389 and
#390; read #390's resolution
comment for the shape it wants, since the next slice builds on this one.
The change, in rust/devlaunch-core/src/clients/ssh.rs:
config_path()honours$DEVPOD_SSH_CONFIGbefore~/.ssh/config.- Context-option paths come only from the already-cached context options —
never a newdevpod context optionsround trip. The cache exists (keyed on
devpod's own config file changing); a new trip here would spend more than the
whole slice saves. Terminal::NoAliassplits, so "no config anywhere" is a legible state
rather than indistinguishable from "config present, alias absent". Silence is
what let this ship.
#390 reports a red test already exists for this. Find it, confirm it is red for
the right reason, and make it green.
Notes for the builder
- Cut from
origin/main; use your own worktree. Other agents are active. - Guards in
rust/:cargo test --workspace,cargo clippy --locked --all-targets -- -D warnings,
cargo fmt --check. - Known pre-existing flake, do not chase:
aid's
a_pasted_multi_line_prompt_arrives_whole_rather_than_leakingunder full-workspace load. - Note for anyone measuring after this lands: scratch-scoped benchmark runs that
setDEVPOD_SSH_CONFIGhave been silently taking the non-pty path, so
before/after numbers taken that way are not comparable across this change.
Activity
blooop commentedon Aug 24, 2026
breadcrumb: built as #433 on
fix/ssh-config-path, cut fromorigin/mainat 57955a3.No red test pre-existed. #421 says #390 reports one; #390's "How it is tested" section proposes it ("red on merged main today") and nothing was ever written, on
mainor onresearch/devpod-ssh-trip. So I proved the red by hand onorigin/mainwith a throwaway test first, since the fixed signature does not exist there:then wrote the permanent ones against the new shape.
All three parts landed.
ssh::config_pathtakes aConfigSourcesand walks devpod's own order (SSH_CONFIG_INCLUDE_PATHcontext option, then$DEVPOD_SSH_CONFIG, then theSSH_CONFIG_PATHcontext option, then~/.ssh/config), expanding a leading~/the wayResolveSSHConfigPathdoes and reading an empty value as unset. The order is read out ofskevetter/devpodv0.26.1 rather than assumed:ConfigureSSHConfigprefers the include path outright, andcmd/root.go::inheritFlagsFromEnvironmentis why devpod reads a variable it never names, since it gives every flag aDEVPOD_<FLAG>default anduphas--ssh-config.The no-round-trip constraint is held by the signature, not by a test. The context-option paths come from a new
already_cached_options, which reads the disk cache and nothing else; neither it norterminal_fortakes aRunner, so neither has anything to ask devpod with. A cache miss answers with devpod's defaults, which is what dl assumed unconditionally before, so a miss is never worse than the bug.The split is three arms, not two.
NoAlias { config }(read the config, this workspace absent),ConfigMissing { looked_in }(nothing readable where devpod publishes),ConfigUnlocatable(no home directory and nothing naming a config, whichXDG_CACHE_HOMEmakes reachable).devpod_host_configured's bool becamessh::Alias, so the collapse cannot come back by accident. Each has its own notice and each names the path dl read.And the e2e harness stops working around it.
route_ssh_throughsymlinked a scratch~/.ssh/configonto the run's config precisely so dl's hardcoded lookup would find it. That symlink is deleted: the scratch home now holds no ssh config at all, sotest/e2e/test_interactive_session.pypassing is what says the resolution order holds. OpenSSH still needs its-Fshim, reading neither$HOMEnor any devpod variable.Guards green in the devcontainer:
cargo test --workspace,clippy --locked --all-targets -- -D warnings,fmt --check, andpytest test/ --ignore=test/e2e(411). e2e not run (no docker/devpod here).public-api.rest.txtupdated for the three notice arms; nothing enters the promisedapitier.The flake behaved as the ticket said.
aid'sa_pasted_multi_line_prompt_arrives_whole_rather_than_leakingfailed once under full-workspace load here, and reproduces onorigin/mainwith this branch stashed: 1 failure in 8 runs under CPU load, 0 in 3 unloaded full-workspace runs. It touches no file this branch changes.Recorded for whoever measures next: the note in the ticket is right and worth repeating on the PR, so it is in the body. Every scratch-scoped run sets
DEVPOD_SSH_CONFIG, so all of them have silently been on the non-pty transport, and a before/after that straddles this commit is comparing two transports rather than two builds.blooop commentedon Aug 24, 2026
breadcrumb: correction to this ticket's own text, on the record. It said "#390 reports a red test already exists for this" — it does not. #390's "How it is tested" section proposed one; nothing existed on
mainor onresearch/devpod-ssh-trip. That was the manager transcribing a proposal as an artefact when it wrote this ticket, which is the same class of error the review of PR #403 caught twice indocs/performance.md. The build proved the red by hand onorigin/mainbefore writing the permanent tests, and said so rather than quietly satisfying the instruction.blooop commentedon Aug 24, 2026
breadcrumb: stage — in review, all checks green at
9c8dc90, awaiting a human merge. PR #433.One review round and one fix round, and the review caught a defect that would have made this worse than the bug it fixes: the PR made dl decide which ssh config to read while leaving
ssh::command_argsemitting no-F, so OpenSSH still resolved the alias throughgetpwuid's~/.ssh/config. On exactly the hosts this ticket targets,dl <ws> -- <cmd>at a terminal would have gone from works without a pty to exit 255, could not resolve hostname. Reproduced twice: by hand on OpenSSH_9.6p1, and then through dl against a real container with the e2e shim deleted, where 6 of 7 terminal tests failed.The fix is the modelling one rather than the symptom: every arm of
Terminalnow carries a path, including the one that works (Usable { config }),Route::Terminalcarries it beside the payload, andcommand_argstakes it as its first parameter, so an invocation with no-Fis not expressible and nothing re-derives the path downstream of the decision.-Fis unconditional by argument, not by omission:$HOMEandgetpwuid's home can differ, so a conditional-Fwould be a guess.The e2e shim is deleted. It prepended
-Fto every invocation, which is the only reason the pty assertions ever passed against a dl emitting none. A harness must not supply the fix under test. What remains is a scratchHOMEwith no.ssh/config, so these tests reaching a container is itself the assertion, and a new e2e test proves the alias resolves with no shim at all.Merging stays human. This ticket stays open until the PR lands.
blooop commentedon Aug 28, 2026
Shipped in PR #433 (merged 2026-08-25):
ssh::config_pathwalks devpod's four-candidate order viaConfigSources, the context-option paths come from the cache-onlyalready_cached_options, andNoAliassplit intoNoAlias/ConfigMissing/ConfigUnlocatable. The review round also made-Funconditional viaTerminal::Usable { config }.