Add response entries isolation validation to E2E test

crates/external_websocket_sync/e2e-test/helix-ws-test-server/go.mod

@@ -136,7 +136,7 @@ require (
 	github.com/hashicorp/go-retryablehttp v0.7.8 // indirect
 	github.com/hashicorp/go-version v1.8.0 // indirect
 	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
-	github.com/helixml/kodit v1.2.1 // indirect
+	github.com/helixml/kodit v1.2.4 // indirect
 	github.com/huandu/xstrings v1.5.0 // indirect
 	github.com/infracloudio/msbotbuilder-go v0.2.5 // indirect
 	github.com/invopop/jsonschema v0.13.0 // indirect
@@ -289,7 +289,7 @@ require (
 	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.41.0 // indirect
 	golang.org/x/term v0.40.0 // indirect
-	golang.org/x/text v0.34.0 // indirect
+	golang.org/x/text v0.35.0 // indirect
 	golang.org/x/time v0.12.0 // indirect
 	golang.org/x/tools v0.42.0 // indirect
 	golang.org/x/xerrors v0.0.0-20240903120638-7835f813f4da // indirect

crates/external_websocket_sync/e2e-test/helix-ws-test-server/go.sum

@@ -520,8 +520,8 @@ github.com/hashicorp/go-version v1.8.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
-github.com/helixml/kodit v1.2.1 h1:m4bwhEuhtYrx8+SoHryushOVR1oF8rKTStwH21vZbtU=
-github.com/helixml/kodit v1.2.1/go.mod h1:bwT0baMTiauunMRF1dAG4cNh6Gw5d8bos28WwajJYWA=
+github.com/helixml/kodit v1.2.4 h1:GjAD+68VlL0CpAzvif7pNVFvY6GtxRQATkcVljfD35o=
+github.com/helixml/kodit v1.2.4/go.mod h1:bwT0baMTiauunMRF1dAG4cNh6Gw5d8bos28WwajJYWA=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/huandu/xstrings v1.5.0 h1:2ag3IFq9ZDANvthTwTiqSSZLjDc+BedvHPAp5tJy2TI=
 github.com/huandu/xstrings v1.5.0/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
@@ -1166,8 +1166,8 @@ golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/text v0.15.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
-golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
-golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
+golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
+golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
 golang.org/x/time v0.12.0 h1:ScB/8o8olJvc+CQPWrK3fPZNfh7qgwCrY0zJmoEQLSE=
 golang.org/x/time v0.12.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

crates/external_websocket_sync/e2e-test/helix-ws-test-server/main.go

@@ -1465,6 +1465,73 @@ func (d *testDriver) validateStore() bool {
 		}
 	}
 
+	// --- RESPONSE ENTRIES ISOLATION VALIDATION ---
+	// Verify that follow-up interactions don't accumulate response_entries from
+	// previous interactions in the same session. This detects the bug where Zed's
+	// flush_streaming_throttle resends ALL entries in the ACP thread and the
+	// accumulator treats old entries as new, ballooning response_entries.
+	log.Println("\n--------------------------------------------------")
+	log.Println("  RESPONSE ENTRIES ISOLATION VALIDATION")
+	log.Println("--------------------------------------------------")
+
+	// Group interactions by session
+	sessionInteractions := make(map[string][]*types.Interaction)
+	for _, i := range interactions {
+		if i.State == types.InteractionStateComplete && len(i.ResponseEntries) > 0 {
+			sessionInteractions[i.SessionID] = append(sessionInteractions[i.SessionID], i)
+		}
+	}
+
+	isolationChecked := 0
+	for sessionID, ints := range sessionInteractions {
+		if len(ints) < 2 {
+			continue // Need at least 2 interactions to check isolation
+		}
+
+		// Sort by creation time
+		sort.Slice(ints, func(a, b int) bool {
+			return ints[a].Created.Before(ints[b].Created)
+		})
+
+		// Collect message_ids from each interaction
+		type parsedEntry struct {
+			MessageID string `json:"message_id"`
+		}
+
+		// For each follow-up interaction, check it doesn't contain message_ids from earlier ones
+		previousMessageIDs := make(map[string]string) // message_id → interaction_id that owns it
+		for _, inter := range ints {
+			var entries []parsedEntry
+			if err := json.Unmarshal(inter.ResponseEntries, &entries); err != nil {
+				continue
+			}
+
+			// Check for leakage: does this interaction contain message_ids from a previous one?
+			for _, e := range entries {
+				if e.MessageID == "" {
+					continue
+				}
+				if ownerID, leaked := previousMessageIDs[e.MessageID]; leaked {
+					errors = append(errors, fmt.Sprintf(
+						"ISOLATION VIOLATION: Interaction %s (session %s) contains message_id %q which belongs to earlier interaction %s — response_entries leaked across interactions",
+						truncate(inter.ID, 12), truncate(sessionID, 12), e.MessageID, truncate(ownerID, 12)))
+				}
+			}
+
+			// Register this interaction's message_ids
+			for _, e := range entries {
+				if e.MessageID != "" {
+					previousMessageIDs[e.MessageID] = inter.ID
+				}
+			}
+			isolationChecked++
+		}
+	}
+	if isolationChecked > 0 {
+		log.Printf("[store] Response entries isolation: checked %d interactions across %d sessions with follow-ups",
+			isolationChecked, len(sessionInteractions))
+	}
+
 	// --- THREAD TITLE VALIDATION ---
 	log.Println("\n--------------------------------------------------")
 	log.Println("  THREAD TITLE VALIDATION")