fix(tui): drop unavailable saved variants

packages/tui/src/context/local.tsx

@@ -10,6 +10,7 @@ import { useClient } from "./client"
 import { RGBA } from "@opentui/core"
 import { readJson, writeJsonAtomic } from "../util/persistence"
 import {
+  availableModelVariant,
   createModelPreferenceRepository,
   cycleModelVariant,
   modelPreferenceKey,
@@ -221,7 +222,14 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
         if (route.data.type === "session") return sessionSelection(route.data.sessionID)
         const model = newSessionModel()
         if (!model) return
-        return { ...model, variant: normalizeModelVariant(preferences.variant[modelPreferenceKey(model)]) }
+        const info = models()?.find((item) => item.providerID === model.providerID && item.id === model.modelID)
+        return {
+          ...model,
+          variant: availableModelVariant(
+            preferences.variant[modelPreferenceKey(model)],
+            info?.variants?.map((item) => item.id) ?? [],
+          ),
+        }
       })
 
       const currentModel = createMemo(() => {
@@ -262,13 +270,12 @@ export const { use: useLocal, provider: LocalProvider } = createSimpleContext({
         if (route.data.type === "session") {
           const sessionID = route.data.sessionID
           const current = sessionSelection(sessionID)
-          const preferred = normalizeModelVariant(
+          const preferred =
             current?.providerID === model.providerID && current.modelID === model.modelID
               ? current.variant
-              : preferences.variant[modelPreferenceKey(model)],
-          )
+              : preferences.variant[modelPreferenceKey(model)]
           const info = models()?.find((item) => item.providerID === model.providerID && item.id === model.modelID)
-          const variant = preferred && info?.variants?.some((item) => item.id === preferred) ? preferred : undefined
+          const variant = availableModelVariant(preferred, info?.variants?.map((item) => item.id) ?? [])
           setSessionDraft(sessionID, { ...model, variant })
           return true
         }

packages/tui/src/model-preference.ts

@@ -39,6 +39,11 @@ export function normalizeModelVariant(value: string | undefined) {
   return value === "default" ? undefined : value
 }
 
+export function availableModelVariant(value: string | undefined, variants: string[]) {
+  const variant = normalizeModelVariant(value)
+  return variant && variants.includes(variant) ? variant : undefined
+}
+
 export function modelPreferenceKey(model: ModelPreferenceModel) {
   return `${model.providerID}/${model.modelID}`
 }

packages/tui/test/model-preference.test.ts

@@ -1,6 +1,6 @@
 import { expect, test } from "bun:test"
 import path from "node:path"
-import { createModelPreferenceRepository, decodeModelPreference } from "../src/model-preference"
+import { availableModelVariant, createModelPreferenceRepository, decodeModelPreference } from "../src/model-preference"
 import { tmpdir } from "./fixture/fixture"
 
 test("repairs known model preferences and preserves unrelated fields", () => {
@@ -19,6 +19,12 @@ test("repairs known model preferences and preserves unrelated fields", () => {
   })
 })
 
+test("drops a saved variant that is no longer available", () => {
+  expect(availableModelVariant("medium", [])).toBeUndefined()
+  expect(availableModelVariant("medium", ["low", "high"])).toBeUndefined()
+  expect(availableModelVariant("medium", ["low", "medium", "high"])).toBe("medium")
+})
+
 test("atomically serializes patches and variant updates", async () => {
   await using tmp = await tmpdir()
   const file = path.join(tmp.path, "model.json")