From 8b8f8b37c35479f747a70a65f069c0d8d4b01dcf Mon Sep 17 00:00:00 2001
From: sigoden <sigoden@gmail.com>
Date: Fri, 28 Jun 2024 07:11:20 +0800
Subject: fix: gemini with functions that have empty parameters (#666)

---
 src/client/vertexai.rs | 13 ++++++++++++-
 src/function.rs        |  9 +++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/client/vertexai.rs b/src/client/vertexai.rs
index cc7e464..a4c4050 100644
--- a/src/client/vertexai.rs
+++ b/src/client/vertexai.rs
@@ -353,7 +353,18 @@ pub fn gemini_build_chat_completions_body(
     }
 
     if let Some(functions) = functions {
-        body["tools"] = json!([{ "functionDeclarations": *functions }]);
+        // Gemini doesn't support functions with parameters that have empty properties, so we need to patch it.
+        let function_declarations: Vec<_> = functions.into_iter().map(|function| {
+            if function.parameters.is_empty_properties() {
+                json!({
+                    "name": function.name,
+                    "description": function.description,
+                })
+            } else {
+                json!(function)
+            }
+        }).collect();
+        body["tools"] = json!([{ "functionDeclarations": function_declarations }]);
     }
 
     Ok(body)
diff --git a/src/function.rs b/src/function.rs
index 8528af5..e99d2c6 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -125,6 +125,15 @@ pub struct JsonSchema {
     pub required: Option<Vec<String>>,
 }
 
+impl JsonSchema {
+    pub fn is_empty_properties(&self) -> bool {
+        match &self.properties {
+            Some(v) => v.is_empty(),
+            None => true,
+        }
+    }
+}
+
 #[derive(Debug, Clone, Default, Deserialize, Serialize)]
 pub struct ToolCall {
     pub name: String,
-- 
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