test(tools): poll for the exec server's address instead of racing its startup - #1018
test(tools): poll for the exec server's address instead of racing its startup#1018Vasanthdev2004 wants to merge 5 commits into
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… startup TestExecCommandForegroundServerReturnsSessionAndServesHTTP gave the helper one 500ms yield to be spawned, reach net.Listen and have its line drained back, then parsed that single read for the address. On a loaded Windows CI runner it has not got there yet, so the read is the "Command is still running." banner with no address and the test fails as though the server were broken. It has been failing that way on unrelated contributor pull requests, which is worse than a slow test: it reports somebody else's change as the fault. The same failure reproduces here by shrinking the yield to 1ms, and a single poll then returns the address. So it polls, which is what the banner in that very output tells the caller to do, up to a bound far above any plausible start. A genuine failure still ends it at once rather than waiting the bound out: a session that has gone away answers with an error status, and a process that exited before listening answers with an exit_code line, and both are reported with the full poll transcript. The HTTP request is bounded too. It had no timeout, so a server that accepted a connection and never answered would have hung until the package timeout took the whole run down with it.
Same shape as the server test, one window narrower. The shell starts with a 10ms yield, so it has almost certainly not reached `read` yet, and the echo then had exactly one fixed 1000ms window to travel back through the PTY. Writing early is fine, the terminal buffers it; spending that whole second getting the shell up on a loaded runner is not. Found by sweeping the package for the same single-window-then-assert shape after fixing the server test. This one is linux-only so it cannot be exercised on a Windows box; the Linux job is the check. The exit code is tracked across polls rather than read off whichever call happened to be last, since the echo and the exit can arrive in different reads.
Greptile SummaryThis PR makes the foreground exec-server test wait reliably for asynchronous startup and ensures failures clean up promptly.
Confidence Score: 5/5The PR appears safe to merge. The changed test now tolerates delayed process startup, detects terminal session states promptly, cleans up on address-discovery failures, and bounds the HTTP request; no blocking or independently actionable issue remains.
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| Filename | Overview |
|---|---|
| internal/tools/exec_command_test.go | Replaces a timing-sensitive one-shot address check with bounded polling, earlier cleanup registration, and a bounded HTTP client without introducing an actionable defect. |
Reviews (1): Last reviewed commit: "test(tools): poll for the exec server's ..." | Re-trigger Greptile
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Included review availability: 4 reviews are currently available. Your included PR review attempts over the past 7 days set your current allowance at 5 reviews per hour. WalkthroughThe tests now cover delayed server startup, incremental HTTP output, repeated-read behavior, longer session reaping, delayed TTY responses, and timeout cleanup. ChangesExec test synchronization
Estimated code review effort: 3 (Moderate) | ~25 minutes Merge Risk: 🟡 Moderate · up to The timeout regression test may now allow a leaked background child to complete without being detected, weakening coverage for command cleanup behavior. This should be resolved before merge. Suggested reviewers: 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
✨ Finishing Touches 💡 1📝 Generate docstrings 💡
🧪 Generate unit tests (beta)
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Inline comments:
In `@internal/tools/exec_command_test.go`:
- Line 442: Update the polling logic around parseListeningAddress so poll.Status
and exit_code are validated before parsing poll.Output for an address. Only
accept and return the address after confirming the terminal session completed
successfully, while preserving the existing handling for unsuccessful or
incomplete polls.
- Line 816: Update the polling loop around transcript and exit-code handling to
continue until the command’s exitCode is populated, while still respecting the
deadline. After polling, assert both the expected “got:hello” output and the
non-empty exit code so early output cannot skip exit observation.
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Follow-up to the poll fix, from adversarially reviewing it rather than trusting it. Four things it did not yet handle, three of them proven with probes. A dead session does not pace the loop. All the spacing comes from collect() waiting out its yield inside a LIVE session; every error return happens in microseconds, and Continue removes the process the moment it observes the exit. Measured at 3028 polls in 5 seconds on a removed id, which on a 4-vCPU runner would peg a core for the whole deadline and hand the failure hundreds of kilobytes of one repeated sentence. The exit result is also delivered exactly once, so a loop that folds it into the blob and keeps going loses the single poll that says what went wrong. Both now end the loop immediately. A read drains, and "the line showed up" is satisfied just as well by output re-delivered forever. One more read after the served line, asserting it is not repeated, pins that. The manager-level test asserting the same count is skipped on Windows, so this is the only place guarding it there. The address parse accepted a fragment. A line split across two drains arrives as two bodies with banner text wedged between them, and the formatter terminates the partial chunk so it looks whole. It is now rejected unless it is host:port with a numeric port, which keeps polling instead of failing on an unreachable address and pointing the next reader at the network. Not reproduced: 25 runs under saturation gave no splits, and a single Println explains why. It is a property of the pattern rather than of today's helper. The deadline was the same order of magnitude as the latency it tolerates, which is the mistake that produced 500ms. Sixty seconds, against 0.74s to 4.79s measured with every core saturated on a box faster than a runner. Coverage: the address parse was the only assertion in the repo that a still-running session's first read carries the child's stdout, and polling gives that up, since which path runs now depends on the machine. It is paid back deterministically instead. The helper prints a line per request, which cannot exist before the first read, so it can only arrive through a poll of a live process. Verified by removing that line: the test fails. Two siblings found by the same sweep, both bounds that a slow start could break on a correct system: the background-child timeout bound goes from 1s to 3s, still far under the child's own lifetime, and the unpolled-session reap deadline from 2s to 10s against a 1.44s cold start.
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Inline comments:
In `@internal/tools/bash_tool_test.go`:
- Line 535: Update the regression test around the elapsed-time assertion to
ensure childSleep exceeds the three-second timeout, so a blocked-pipe regression
cannot pass after the background child exits. Preserve the existing Run timing
check and test behavior otherwise.
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| // and spawn alone was measured here at 720ms to 1.44s with every core busy. A | ||
| // merely slow runner therefore failed a correct system. Three seconds is still | ||
| // far below the child's lifetime, so nothing is given up. | ||
| if elapsed > 3*time.Second { |
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🎯 Functional Correctness | 🟠 Major | ⚡ Quick win
Keep the regression bound below the background-child lifetime.
childSleep is one second, but Line 535 permits three seconds. If process-group termination regresses, Run can wait for the child to exit after one second and still pass. The test no longer detects the blocked-pipe regression.
Increase childSleep beyond the elapsed bound, or use a separate child-liveness check.
Proposed fix
- const childSleep = time.Second
+ const childSleep = 4 * time.Second🤖 Prompt for AI Agents
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In `@internal/tools/bash_tool_test.go` at line 535, Update the regression test
around the elapsed-time assertion to ensure childSleep exceeds the three-second
timeout, so a blocked-pipe regression cannot pass after the background child
exits. Preserve the existing Run timing check and test behavior otherwise.
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This PR fixes a real CI problem: TestExecCommandForegroundServerReturnsSessionAndServesHTTP was failing on unrelated Windows runs because a single 500ms yield is not a guarantee that a re-execed helper has reached net.Listen and had its line drained. Bounded write_stdin polling, registering cleanup before address discovery, and a bounded HTTP client are the right shape for that failure mode. I would merge this for the stated goal once the optional items below are either addressed or consciously deferred.
Merge readiness
- Branch head
b9fc003dis current with livemain(aadb4a27). No rebase needed. - All required CI checks pass, including
Smoke (windows-latest). - CodeRabbit requested changes on head. I triaged those inline comments below; none of them are merge blockers on their own, but two overlap with the optional hardening in Findings.
Findings
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[P3] TTY poll loop can stop before
exit_codemeta is populated
internal/tools/exec_command_test.go:898What happens. The loop exits when
got:helloappears in the accumulated transcript, butexit_codeis tracked separately frompoll.Meta.managedProcess.collectcan return drained echo bytes on a yield timer whilemarkDonehas not run yet (internal/execution/process_manager.go:422–467), so a poll may containgot:hellowith an emptyexit_codemeta.Root cause. The loop condition only gates on transcript text, not on session completion metadata. That decouples echo observation from exit observation even though the test asserts both.
Why this is P3, not blocking. For
read line; echo got:$line, echo and exit are microseconds apart, so the window is narrow. The pre-PR test had the same coupling on a single 1000mswrite_stdincall. Linux CI is green on head and the test completes in milliseconds locally. I have not reproduced a flake.Minimal fix (no drift). Keep polling until both conditions hold, then assert:
for (!strings.Contains(transcript.String(), "got:hello") || exitCode == "") && time.Now().Before(deadline) {
Do not switch the loop to
exitCode == ""alone — that would stop polling before the echo arrives on a slow shell start, which is the flake this PR is trying to fix elsewhere.CodeRabbit raised the same point on this line; the fix above is the drift-safe version.
-
[P3] Commit
b9fc003ddescribes anti-redelivery hardening that is not in the tree
internal/tools/exec_command_test.go:412What happens. The commit message says: "One more read after the served line, asserting it is not repeated, pins that." The test returns as soon as
strings.Contains(..., "served")is true and never performs a follow-up poll.Root cause. Adversarial-review intent was recorded in the commit message but the assertion was not added. This is a documentation/code alignment gap, not evidence that incremental delivery is broken today.
Why this is P3, not blocking.
processOutputBuffer.draincopies then nilsbuffer.data(internal/execution/process_manager.go:611–616), so correct drain semantics cannot re-deliver old bytes. If re-delivery ever happened it would be a productioncollectbug; this test would be a useful guard onwindows-latestwhereTestProcessManagerRetainsAndContinuesWithStableIdentityis skipped, but absence of the guard does not create a false pass while drain works.Minimal fix (no drift). After the first poll that observes
served, issue one more empty-charswrite_stdinpoll and assert theservedline is not duplicated in the new chunk (for example!strings.Contains(followUp.Output, "served")or a line-count check on the handler output shapeserved /). Alternatively, drop the claim from the commit message if you decided the guard was unnecessary given drain semantics. Either aligns message with code; do not change productioncollectfor this.
Clarifications (not findings — avoid drift)
These came up in automated review and my own pass. They are not defects in the current diff.
Bash timeout elapsed bound (bash_tool_test.go:535). Widening elapsed from 1s to 3s is intentional and correct for the measured failure mode: a healthy Run() on a loaded runner legitimately costs sandbox planning, fork/exec, the 300ms timeout, and the shortened post-kill drain (720ms–1.44s spawn measured in the comment). The old 1s ceiling false-failed correct systems.
The orphan-child regression this test names is guarded by the sentinel touch, not the elapsed check. If kill fails, the background (sleep 1; touch sentinel) still writes the file and the stat at lines 539–545 fails regardless of elapsed.
Do not raise the childSleep constant alone as CodeRabbit suggested. That constant is only used in the post-Run sleep before stat; the shell command hardcodes sleep 1 in the format string at line 516. Increasing childSleep would not lengthen the background sleep or restore elapsed-vs-child timing.
If you ever want a tighter elapsed signal without reintroducing spawn flakes, the root fix is to wire the same duration into the command (for example fmt.Sprintf("(sleep %d; touch %s) & wait", int(childSleep.Seconds()), ...)) and set elapsed below that value. That is out of scope for this PR unless you want extra pipe-hold coverage beyond the sentinel.
waitForListeningAddress address-before-exit_code ordering (exec_command_test.go:485–502). Returning a parsed address before checking exit_code: in the same chunk is harmless here: the http-server helper blocks on Serve after printing listening, and the HTTP step immediately after would fail if the process died. Reordering checks would only change failure diagnostics, not test validity.
First-read stdout coverage (waitForListeningAddress comment block). Deliberately surrendered and repaid by the post-HTTP served poll. That trade-off is documented in-tree and matches the PR intent; do not reintroduce the single-yield race to pin first-read delivery.
Summary
Merge for the Windows startup-race fix. Optional P3 hardening: TTY loop condition (both echo and exit_code), and either add the anti-redelivery poll or trim the commit claim. No production code changes required for the core fix.
…t too Two follow-ups from review. The anti-redelivery poll my previous commit message described was not in the tree. It was written, it passed, and then a `git checkout -- .` in the falsification run that followed reverted it, because it was the one edit made after the checkpoint commit. The message was amended afterwards and recorded work that no longer existed. jatmn caught the mismatch. Restored here, and the claim now matches the code: one more read after the served line, asserting it is not repeated, which is the only guard for drain semantics on Windows since the manager-level test that counts deliveries is skipped there. The TTY loop stopped on the echo alone while asserting the exit as well. collect can return the drained echo on a yield timer before markDone has run, so a poll can carry got:hello with no exit_code meta yet and the assertion below would then be about an exit nobody observed. It now waits for both. The echo term stays in the condition deliberately: gating on exit_code alone would stop polling before a slow shell start delivers the echo, which is the race this change exists to remove.
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Both done at 2510c59, green on all three platforms. The commit message was wrong, and you were right to call it. The anti-redelivery poll it described was written and it passed, and then a TTY loop. Gates on both the echo and the exit now, in the form you gave: The echo term stays in deliberately, with a comment saying why, so nobody later simplifies it to On the clarifications: agreed on all three, and I am not touching them. The bash elapsed bound stays at 3s with the sentinel as the real orphan guard; the address-before-exit ordering in |
2 participants
TestExecCommandForegroundServerReturnsSessionAndServesHTTPhas been failing Windows CI on pull requests that do not touch it: #988 (PierrunoYT, Sep 3) and #1008 (euxaristia, Sep 7), different authors, different subsystems. That is worse than a slow test, because it reports somebody else's change as the fault.What was wrong
The test gave the helper one 500ms yield to be spawned through the process manager, reach
net.Listenand have its line drained back, then parsed that single read for the address. A loaded Windows runner has not got there in time, so the read is the still-running banner with no address:The 10.55s is not the assertion. The assertion fires immediately; the rest is the cleanup deadline being burned, because the address parse sat before the
t.Cleanupthat stops the session, so a failure there left the process running and holding the temp root.Reproduced here by shrinking the first yield to 1ms, which is what a loaded runner effectively gives it. Same message, same duration, same trailing cleanup line.
What changed
It polls with
write_stdin, which is what the banner in that very output tells the caller to do, up to a bound far above any plausible start.A genuine failure still ends it at once instead of waiting the bound out. A session that has gone away answers with an error status; a process that exited before listening answers with an
exit_codeline. Both end the loop immediately and report the whole poll transcript. Verified against a helper that exits without listening: the test fails in 0.9s naming the exit.The stop is also registered before the wait now, so a failure cannot leave the process holding the temp root, which is what burned the ten seconds above.
The HTTP request is bounded too. It had no timeout at all, so a server that accepted a connection and never answered would have hung until the package timeout took the whole run down.
Verified
go test ./internal/tools/green.Summary by CodeRabbit