Sync upstream Gemini-CLI v0.8.2 (#838)

packages/core/src/config/models.ts

@@ -6,9 +6,47 @@
 
 export const DEFAULT_QWEN_MODEL = 'coder-model';
 export const DEFAULT_QWEN_FLASH_MODEL = 'coder-model';
+export const DEFAULT_QWEN_EMBEDDING_MODEL = 'text-embedding-v4';
 
 export const DEFAULT_GEMINI_MODEL = 'coder-model';
 export const DEFAULT_GEMINI_FLASH_MODEL = 'gemini-2.5-flash';
 export const DEFAULT_GEMINI_FLASH_LITE_MODEL = 'gemini-2.5-flash-lite';
 
+export const DEFAULT_GEMINI_MODEL_AUTO = 'auto';
+
 export const DEFAULT_GEMINI_EMBEDDING_MODEL = 'gemini-embedding-001';
+
+// Some thinking models do not default to dynamic thinking which is done by a value of -1
+export const DEFAULT_THINKING_MODE = -1;
+
+/**
+ * Determines the effective model to use, applying fallback logic if necessary.
+ *
+ * When fallback mode is active, this function enforces the use of the standard
+ * fallback model. However, it makes an exception for "lite" models (any model
+ * with "lite" in its name), allowing them to be used to preserve cost savings.
+ * This ensures that "pro" models are always downgraded, while "lite" model
+ * requests are honored.
+ *
+ * @param isInFallbackMode Whether the application is in fallback mode.
+ * @param requestedModel The model that was originally requested.
+ * @returns The effective model name.
+ */
+export function getEffectiveModel(
+  isInFallbackMode: boolean,
+  requestedModel: string,
+): string {
+  // If we are not in fallback mode, simply use the requested model.
+  if (!isInFallbackMode) {
+    return requestedModel;
+  }
+
+  // If a "lite" model is requested, honor it. This allows for variations of
+  // lite models without needing to list them all as constants.
+  if (requestedModel.includes('lite')) {
+    return requestedModel;
+  }
+
+  // Default fallback for Gemini CLI.
+  return DEFAULT_GEMINI_FLASH_MODEL;
+}