fix: resolve race condition in context condensing prompt input (#10876)

Author: hannesrudolph

AGENTS.md

@@ -0,0 +1,5 @@
+# AGENTS.md
+
+This file provides guidance to agents when working with code in this repository.
+
+- Settings View Pattern: When working on `SettingsView`, inputs must bind to the local `cachedState`, NOT the live `useExtensionState()`. The `cachedState` acts as a buffer for user edits, isolating them from the `ContextProxy` source-of-truth until the user explicitly clicks "Save". Wiring inputs directly to the live state causes race conditions.

webview-ui/src/components/settings/PromptsSettings.tsx

@@ -23,13 +23,17 @@ import { SearchableSetting } from "./SearchableSetting"
 interface PromptsSettingsProps {
 	customSupportPrompts: Record<string, string | undefined>
 	setCustomSupportPrompts: (prompts: Record<string, string | undefined>) => void
+	customCondensingPrompt?: string
+	setCustomCondensingPrompt?: (value: string) => void
 	includeTaskHistoryInEnhance?: boolean
 	setIncludeTaskHistoryInEnhance?: (value: boolean) => void
 }
 
 const PromptsSettings = ({
 	customSupportPrompts,
 	setCustomSupportPrompts,
+	customCondensingPrompt: propsCustomCondensingPrompt,
+	setCustomCondensingPrompt: propsSetCustomCondensingPrompt,
 	includeTaskHistoryInEnhance: propsIncludeTaskHistoryInEnhance,
 	setIncludeTaskHistoryInEnhance: propsSetIncludeTaskHistoryInEnhance,
 }: PromptsSettingsProps) => {
@@ -40,12 +44,16 @@ const PromptsSettings = ({
 		setEnhancementApiConfigId,
 		condensingApiConfigId,
 		setCondensingApiConfigId,
-		customCondensingPrompt,
-		setCustomCondensingPrompt,
+		customCondensingPrompt: contextCustomCondensingPrompt,
+		setCustomCondensingPrompt: contextSetCustomCondensingPrompt,
 		includeTaskHistoryInEnhance: contextIncludeTaskHistoryInEnhance,
 		setIncludeTaskHistoryInEnhance: contextSetIncludeTaskHistoryInEnhance,
 	} = useExtensionState()
 
+	// Use props if provided, otherwise fall back to context
+	const customCondensingPrompt = propsCustomCondensingPrompt ?? contextCustomCondensingPrompt
+	const setCustomCondensingPrompt = propsSetCustomCondensingPrompt ?? contextSetCustomCondensingPrompt
+
 	// Use props if provided, otherwise fall back to context
 	const includeTaskHistoryInEnhance = propsIncludeTaskHistoryInEnhance ?? contextIncludeTaskHistoryInEnhance ?? true
 	const setIncludeTaskHistoryInEnhance = propsSetIncludeTaskHistoryInEnhance ?? contextSetIncludeTaskHistoryInEnhance
@@ -76,10 +84,6 @@ const PromptsSettings = ({
 
 		if (type === "CONDENSE") {
 			setCustomCondensingPrompt(finalValue ?? supportPrompt.default.CONDENSE)
-			vscode.postMessage({
-				type: "updateCondensingPrompt",
-				text: finalValue ?? supportPrompt.default.CONDENSE,
-			})
 			// Also update the customSupportPrompts to trigger change detection
 			const updatedPrompts = { ...customSupportPrompts }
 			if (finalValue === undefined) {
@@ -102,10 +106,6 @@ const PromptsSettings = ({
 	const handleSupportReset = (type: SupportPromptType) => {
 		if (type === "CONDENSE") {
 			setCustomCondensingPrompt(supportPrompt.default.CONDENSE)
-			vscode.postMessage({
-				type: "updateCondensingPrompt",
-				text: supportPrompt.default.CONDENSE,
-			})
 			// Also update the customSupportPrompts to trigger change detection
 			const updatedPrompts = { ...customSupportPrompts }
 			delete updatedPrompts[type]

webview-ui/src/components/settings/SettingsView.tsx

@@ -900,6 +900,10 @@ const SettingsView = forwardRef<SettingsViewRef, SettingsViewProps>(({ onDone, t
 							<PromptsSettings
 								customSupportPrompts={customSupportPrompts || {}}
 								setCustomSupportPrompts={setCustomSupportPromptsField}
+								customCondensingPrompt={customCondensingPrompt}
+								setCustomCondensingPrompt={(value) =>
+									setCachedStateField("customCondensingPrompt", value)
+								}
 								includeTaskHistoryInEnhance={includeTaskHistoryInEnhance}
 								setIncludeTaskHistoryInEnhance={(value) =>
 									setCachedStateField("includeTaskHistoryInEnhance", value)