fix: handle empty 200 response from PUT /v1/license (#39)

The Redis Enterprise API returns 200 with an empty body for license
uploads, but the client tried to deserialize it as JSON, causing an
EOF parse error even though the upload succeeded.

Adds put_action() method (matching existing post_action pattern) for
endpoints that return no content. LicenseHandler::update() now uses
put_action + a follow-up GET to return the installed license.

Fixes redis-developer/redisctl#895.

Author: joshrotenberg

src/client.rs

@@ -489,6 +489,34 @@ impl EnterpriseClient {
         }
     }
 
+    /// PUT request for actions that return no content (or may return an empty body)
+    pub async fn put_action<B: Serialize>(&self, path: &str, body: &B) -> Result<()> {
+        let url = self.normalize_url(path);
+        debug!("PUT {}", url);
+        trace!("Request body: {:?}", serde_json::to_value(body).ok());
+
+        let response = self
+            .client
+            .put(&url)
+            .basic_auth(&self.username, Some(&self.password))
+            .json(body)
+            .send()
+            .await
+            .map_err(|e| self.map_reqwest_error(e, &url))?;
+
+        trace!("Response status: {}", response.status());
+        if response.status().is_success() {
+            Ok(())
+        } else {
+            let status = response.status();
+            let text = response.text().await.unwrap_or_default();
+            Err(RestError::ApiError {
+                code: status.as_u16(),
+                message: text,
+            })
+        }
+    }
+
     /// POST request with multipart/form-data for file uploads
     pub async fn post_multipart<T: DeserializeOwned>(
         &self,

src/license.rs

@@ -116,8 +116,13 @@ impl LicenseHandler {
     }
 
     /// Update license
+    ///
+    /// The Redis Enterprise API may return 200 with an empty body for this
+    /// endpoint, so we use put_action (which tolerates empty responses) and
+    /// follow up with a GET to return the installed license.
     pub async fn update(&self, request: LicenseUpdateRequest) -> Result<License> {
-        self.client.put("/v1/license", &request).await
+        self.client.put_action("/v1/license", &request).await?;
+        self.get().await
     }
 
     /// Get license usage statistics

tests/license_tests.rs

@@ -104,10 +104,19 @@ async fn test_license_update() {
         license: "new-license-key-12345".to_string(),
     };
 
+    // PUT /v1/license returns 200 with empty body (real API behavior)
     Mock::given(method("PUT"))
         .and(path("/v1/license"))
         .and(basic_auth("admin", "password"))
         .and(body_json(&update_request))
+        .respond_with(ResponseTemplate::new(200))
+        .mount(&mock_server)
+        .await;
+
+    // Follow-up GET /v1/license returns the installed license
+    Mock::given(method("GET"))
+        .and(path("/v1/license"))
+        .and(basic_auth("admin", "password"))
         .respond_with(success_response(json!({
             "key": "new-license-key-12345",
             "type": "production",