fix: preserve condensation summary during task resume (#11487) (#11488)

Co-authored-by: Sannidhya <sann@Sannidhyas-MacBook-Pro.local>

src/core/condense/__tests__/rewind-after-condense.spec.ts

@@ -518,4 +518,56 @@ describe("Rewind After Condense - Issue #8295", () => {
 			})
 		})
 	})
+
+	describe("Resume after condense preserves summary", () => {
+		it("should keep condensed messages filtered when a new user message is added after summary", () => {
+			const condenseId = "summary-resume-test"
+
+			// Simulate post-condensation state: all old messages tagged, summary at end,
+			// then a new user message added after resume (the fix preserves summary)
+			const historyAfterResume: ApiMessage[] = [
+				{ role: "user", content: "Original task", ts: 100, condenseParent: condenseId },
+				{ role: "assistant", content: "Response 1", ts: 200, condenseParent: condenseId },
+				{ role: "user", content: "Follow-up", ts: 300, condenseParent: condenseId },
+				{ role: "assistant", content: "Response 2", ts: 400, condenseParent: condenseId },
+				{
+					role: "user",
+					content: [{ type: "text", text: "## Conversation Summary\nSummary of work done" }],
+					ts: 401,
+					isSummary: true,
+					condenseId,
+				},
+				// New user message added after resume (no isSummary, no condenseId)
+				{ role: "user", content: [{ type: "text", text: "Please continue with the next step" }], ts: 500 },
+			]
+
+			const effective = getEffectiveApiHistory(historyAfterResume)
+
+			// Should only include summary + new message (fresh start model)
+			expect(effective).toHaveLength(2)
+			expect(effective[0].isSummary).toBe(true)
+			expect(effective[1].ts).toBe(500)
+		})
+
+		it("should restore ALL messages if summary is missing (the bug scenario before fix)", () => {
+			const condenseId = "summary-bug-demo"
+
+			// Simulate the bug: summary was stripped during resume, replaced with regular message.
+			// condenseParent tags still exist but point to a non-existent summary.
+			const historyWithoutSummary: ApiMessage[] = [
+				{ role: "user", content: "Original task", ts: 100, condenseParent: condenseId },
+				{ role: "assistant", content: "Response 1", ts: 200, condenseParent: condenseId },
+				{ role: "user", content: "Follow-up", ts: 300, condenseParent: condenseId },
+				{ role: "assistant", content: "Response 2", ts: 400, condenseParent: condenseId },
+				// Summary was REMOVED and replaced with a regular user message (no isSummary)
+				{ role: "user", content: [{ type: "text", text: "Summary content merged with new input" }], ts: 500 },
+			]
+
+			const effective = getEffectiveApiHistory(historyWithoutSummary)
+
+			// Without the summary, ALL messages are restored (orphaned condenseParent)
+			// This demonstrates the bug: condensation is effectively undone
+			expect(effective).toHaveLength(5)
+		})
+	})
 })

src/core/task/Task.ts

@@ -2099,7 +2099,17 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 		if (existingApiConversationHistory.length > 0) {
 			const lastMessage = existingApiConversationHistory[existingApiConversationHistory.length - 1]
 
-			if (lastMessage.role === "assistant") {
+			if (lastMessage.isSummary) {
+				// IMPORTANT: If the last message is a condensation summary, we must preserve it
+				// intact. The summary message carries critical metadata (isSummary, condenseId)
+				// that getEffectiveApiHistory() uses to filter out condensed messages.
+				// Removing or merging it would destroy this metadata, causing all condensed
+				// messages to become "orphaned" and restored to active status — effectively
+				// undoing the condensation and sending the full history to the API.
+				// See: https://github.com/RooCodeInc/Roo-Code/issues/11487
+				modifiedApiConversationHistory = [...existingApiConversationHistory]
+				modifiedOldUserContent = []
+			} else if (lastMessage.role === "assistant") {
 				const content = Array.isArray(lastMessage.content)
 					? lastMessage.content
 					: [{ type: "text", text: lastMessage.content }]