Fix the try: guard shared test state with mutexes, pgxpool over one conn, a short batch gap for integration builds, unique+forced database drops (issues 1431, 1524, 1517)

modules/mesh-mail-web/cmd/mesh-mail-web/mailwrite_integration_test.go

@@ -12,9 +12,47 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"sync"
 	"testing"
 )
 
+// recordedArgs is a mutex-guarded holder: a stand-in's own closure (called from the player's readLoop
+// goroutine, runtime_integration_test.go's handleBundleRequest) records what it was asked here, and the
+// test (its own, main goroutine) reads it back safely afterward. The coordinator's own fix for issue 1523:
+// the merge check's `go test -race` found this exact unsynchronized pattern — a bare variable written by
+// one goroutine and read by another, with no memory synchronization the race detector can see (the two
+// communicate only over a stdio pipe and an HTTP round trip, neither of which it tracks as ordinary Go
+// synchronization).
+type recordedArgs struct {
+	mu   sync.Mutex
+	args map[string]any
+	set  bool
+}
+
+func (r *recordedArgs) record(args map[string]any) {
+	r.mu.Lock()
+	r.args, r.set = args, true
+	r.mu.Unlock()
+}
+
+func (r *recordedArgs) clear() {
+	r.mu.Lock()
+	r.args, r.set = nil, false
+	r.mu.Unlock()
+}
+
+func (r *recordedArgs) get() map[string]any {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return r.args
+}
+
+func (r *recordedArgs) wasSet() bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return r.set
+}
+
 func TestAcceptanceMailCorrectionAndUndoReachTheStandIn(t *testing.T) {
 	mw := startMailWeb(t, acceptanceAccounts(), []string{"alice"})
 	mw.mailReading.Status = func(map[string]any) (any, error) {
@@ -33,13 +71,13 @@ func TestAcceptanceMailCorrectionAndUndoReachTheStandIn(t *testing.T) {
 			{"id": 9, "sender-name": "Bob", "subject": "fyi", "change": "mark: neither -> matters", "made": "2026-10-20T10:00:00Z"},
 		}}, nil
 	}
-	var correctArgs, undoArgs map[string]any
+	var correctArgs, undoArgs recordedArgs
 	mw.mailReading.Correct = func(args map[string]any) (any, error) {
-		correctArgs = args
+		correctArgs.record(args)
 		return map[string]any{"id": args["id"]}, nil
 	}
 	mw.mailReading.Undo = func(args map[string]any) (any, error) {
-		undoArgs = args
+		undoArgs.record(args)
 		return map[string]any{"undone": args["id"]}, nil
 	}
 
@@ -65,19 +103,19 @@ func TestAcceptanceMailCorrectionAndUndoReachTheStandIn(t *testing.T) {
 	if correctResp.StatusCode != http.StatusOK {
 		t.Fatalf("the correction: status %d: %s", correctResp.StatusCode, correctBody)
 	}
-	if correctArgs["id"] != float64(1) || correctArgs["mark"] != "matters" || correctArgs["group"] != "bills" {
-		t.Fatalf("mail-reading.correct was asked %v, want id 1, mark matters, group bills", correctArgs)
+	if got := correctArgs.get(); got["id"] != float64(1) || got["mark"] != "matters" || got["group"] != "bills" {
+		t.Fatalf("mail-reading.correct was asked %v, want id 1, mark matters, group bills", got)
 	}
 
 	// Without the token, the correction never reaches the stand-in (1523/AC1).
-	correctArgs = nil
+	correctArgs.clear()
 	noTokenResp := doForm(t, mw, "/mail-correct", url.Values{"id": {"1"}, "mark": {"neither"}}, cookie)
 	_ = noTokenResp.Body.Close()
 	if noTokenResp.StatusCode != http.StatusForbidden {
 		t.Fatalf("a correction with no token: status %d, want 403", noTokenResp.StatusCode)
 	}
-	if correctArgs != nil {
-		t.Fatalf("mail-reading.correct was asked %v with no token", correctArgs)
+	if correctArgs.wasSet() {
+		t.Fatalf("mail-reading.correct was asked %v with no token", correctArgs.get())
 	}
 
 	// 1523/AC2: an undo posted with the session's own token reaches the stand-in's Undo.
@@ -87,8 +125,8 @@ func TestAcceptanceMailCorrectionAndUndoReachTheStandIn(t *testing.T) {
 	if undoResp.StatusCode != http.StatusOK {
 		t.Fatalf("the undo: status %d: %s", undoResp.StatusCode, undoBody)
 	}
-	if undoArgs["id"] != float64(9) {
-		t.Fatalf("mail-reading.undo was asked %v, want id 9", undoArgs)
+	if got := undoArgs.get(); got["id"] != float64(9) {
+		t.Fatalf("mail-reading.undo was asked %v, want id 9", got)
 	}
 
 	// 1523/AC4: nothing of mail is read but through mail-store — this flow never asks mail-store.search or