Preserve config writes for unrelated load errors

codex-rs/app-server/src/config_manager_service.rs

@@ -320,15 +320,21 @@ impl ConfigManager {
                 format!("Invalid configuration: {err}"),
             )
         })?;
-        codex_core::config::validate_materialized_config_from_layer_stack(
-            self.codex_home().to_path_buf(),
-            updated_layers.clone(),
-            codex_core::config::ConfigOverrides::default(),
-        )
-        .await
-        .map_err(|err| {
-            ConfigManagerError::write(ConfigWriteErrorCode::ConfigValidationError, err.to_string())
-        })?;
+        let materialized_config_validation =
+            codex_core::config::validate_materialized_config_from_layer_stack(
+                self.codex_home().to_path_buf(),
+                updated_layers.clone(),
+                codex_core::config::ConfigOverrides::default(),
+            )
+            .await;
+        if let Err(err) = materialized_config_validation
+            && codex_core::config::is_windows_sandbox_network_proxy_incompatible_error(&err)
+        {
+            return Err(ConfigManagerError::write(
+                ConfigWriteErrorCode::ConfigValidationError,
+                err.to_string(),
+            ));
+        }
 
         if !config_edits.is_empty() {
             ConfigEditsBuilder::for_config_path(provided_path.as_path())

codex-rs/app-server/src/config_manager_service_tests.rs

@@ -742,6 +742,37 @@ personality = true
     );
 }
 
+#[tokio::test]
+async fn write_value_ignores_unrelated_materialized_config_errors() -> Result<()> {
+    let tmp = tempdir().expect("tempdir");
+    let config_path = tmp.path().join(CONFIG_TOML_FILE);
+    std::fs::write(&config_path, "model_provider = \"missing\"\n")?;
+
+    let service = ConfigManager::without_managed_config_for_tests(tmp.path().to_path_buf());
+    service
+        .write_value(ConfigValueWriteParams {
+            file_path: Some(config_path.display().to_string()),
+            key_path: "features.personality".to_string(),
+            value: serde_json::json!(true),
+            merge_strategy: MergeStrategy::Replace,
+            expected_version: None,
+        })
+        .await?;
+
+    let actual: TomlValue = toml::from_str(&std::fs::read_to_string(&config_path)?)?;
+    let expected: TomlValue = toml::from_str(
+        r#"
+model_provider = "missing"
+
+[features]
+personality = true
+"#,
+    )?;
+    assert_eq!(actual, expected);
+
+    Ok(())
+}
+
 #[cfg(target_os = "windows")]
 #[tokio::test]
 async fn batch_write_rejects_unelevated_windows_sandbox_with_network_proxy() -> Result<()> {