[piekstra]

Summary

Fixes the intermittent HTTP/1.x transport connection broken: http: CloseIdleConnections called failures in jtk tests. Seen on main in TestRunDelete_MultipleIssues, TestRunDelete (remote links), TestRunDelete_Force (fields), TestDeleteFieldContext and TestRunRemove_IDOnly (sprints).

Root cause: client.New built an http.Client with no Transport, so every client shared http.DefaultTransport. httptest.Server.Close calls http.DefaultTransport.CloseIdleConnections() on every test server shutdown. For a response without a body (a 204, or an empty 200), net/http puts the connection back in the idle pool in readLoop before it hands the response to the waiting roundTrip. If another parallel test closes its server in that window, the connection is closed with errCloseIdleConns, roundTrip sees the close before the response, and the request fails. Every failing test uses a bodiless response (DELETE 204, field trash, backlog move).

Changes:

• shared/client: each Client gets its own http.DefaultTransport.Clone(), so other code closing the default pool cannot touch its connections. The clone keeps the default proxy, dial, TLS and HTTP/2 settings. This covers jtk and cfl, which both build on this client.
• tools/jtk/internal/cmd/issues/delete_test.go: when runDelete fails, the test prints the per-issue errors it wrote to stderr. The returned error is only already reported (1 of 3 issue(s) failed), which hid the transport error in CI.

Tests

Reproduction: the flake did not reproduce at package level locally (issues.test -test.count=200 -test.cpu 1,2,8: 0 failures in 600 package runs), so I reproduced the mechanism directly with a temporary rig in shared/client (source below, not committed): 4 goroutines each issue DELETEs returning 204 against their own httptest server through client.New, while another goroutine calls http.DefaultTransport.(*http.Transport).CloseIdleConnections() every 2ms, the same call httptest.Server.Close makes. Command, 15s per run:

REPRO_SECS=15 REPRO_WORKERS=4 REPRO_BURNERS=0 REPRO_CLOSE_US=2000 GOMAXPROCS=4 go test -race -run TestReproCloseIdleRace -v ./client/

	runs	runs with a failure	failed requests	requests
before	20	6	8	7,846,683
after	20	0	0	8,835,001

Every failure before was the exact CI error: request failed: Delete "http://127.0.0.1:<port>/x": net/http: HTTP/1.x transport connection broken: http: CloseIdleConnections called.

• New TestNew/owns_its_transport asserts clients do not share http.DefaultTransport or each other's transport.
• go test -race ./... and golangci-lint run ./... pass in shared, tools/jtk and tools/cfl.

Reproduction rig

package client

import (
	"context"
	"net/http"
	"net/http/httptest"
	"os"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	"time"
)

func envInt(k string, d int) int {
	if v, err := strconv.Atoi(os.Getenv(k)); err == nil {
		return v
	}
	return d
}

// Temporary reproduction rig, not committed.
func TestReproCloseIdleRace(t *testing.T) {
	dur := time.Duration(envInt("REPRO_SECS", 20)) * time.Second
	closeEvery := time.Duration(envInt("REPRO_CLOSE_US", 2000)) * time.Microsecond
	stop := make(chan struct{})
	var bg sync.WaitGroup
	bg.Add(1)
	go func() {
		defer bg.Done()
		for {
			select {
			case <-stop:
				return
			case <-time.After(closeEvery):
			}
			// Same call httptest.Server.Close makes on every test server shutdown.
			http.DefaultTransport.(*http.Transport).CloseIdleConnections()
		}
	}()
	for b := 0; b < envInt("REPRO_BURNERS", 8); b++ {
		bg.Add(1)
		go func() {
			defer bg.Done()
			x := 0
			for {
				select {
				case <-stop:
					return
				default:
				}
				for i := 0; i < 10000; i++ {
					x += i
				}
			}
		}()
	}
	var fails, total atomic.Int64
	var wg sync.WaitGroup
	deadline := time.Now().Add(dur)
	for g := 0; g < envInt("REPRO_WORKERS", 4); g++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			srv := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				w.WriteHeader(http.StatusNoContent)
			}))
			srv.Start()
			defer srv.Close()
			c := New(srv.URL, "e", "t", nil)
			for time.Now().Before(deadline) {
				total.Add(1)
				if _, err := c.Delete(context.Background(), "/x"); err != nil {
					if fails.Add(1) == 1 {
						t.Logf("first failure: %v", err)
					}
					if !strings.Contains(err.Error(), "CloseIdleConnections called") {
						t.Errorf("other error: %v", err)
						return
					}
				}
			}
		}()
	}
	wg.Wait()
	close(stop)
	bg.Wait()
	t.Logf("CloseIdleConnections failures: %d of %d requests", fails.Load(), total.Load())
	if fails.Load() > 0 {
		t.Fail()
	}
}

[monit-reviewer]

Automated PR Review

Reviewed commit: 7eafdb1e9a35
Profile: claude-monit-reviewer - Posting as: monit-reviewer

Summary

Reviewer	Findings
go:implementation-tests	0
architecture:solid-reviewer-agnostic	0

Reviewer Coverage

• go:implementation-tests — complete (broad); skipped: none; constraints: none
• architecture:solid-reviewer-agnostic — complete (broad); inspected 2 assigned files (3 inspected across reviewers): shared/client/client.go, shared/client/client_test.go; skipped: none; constraints: Only four production call sites construct client.New (jtk and cfl api packages), each once per command, so a per-Client transport does not multiply connection pools in practice. Ran go test ./client/ in shared (passes); did not run the full jtk/cfl suites or the PR's reproduction rig.

Inspected files (3)

• shared/client/client.go
• shared/client/client_test.go
• tools/jtk/internal/cmd/issues/delete_test.go

0 PR discussion threads considered. 0 summarized; 0 resolved.

---

Completed in 1m 47s | ~$1.16 (est.) | claude-sonnet-5, claude-opus-5-5 | cr 0.10.318

Field	Value
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Engine	claude_cli · claude-sonnet-5, claude-opus-5-5
Reviewed by	cr · monit-reviewer
Duration	1m 47s wall · 2m 01s compute
Cost	~$1.16 (est.)
Pricing basis	anthropic-public-2026-09-23
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