fix truncated sqlpage function error traces

Author: lovasoa

CHANGELOG.md

@@ -16,6 +16,7 @@
 - New `options_source` parameter in the form component. This allows to dynamically load options for dropdowns from a different SQL file.
  - This allows easily implementing autocomplete for form fields with a large number of possible options.
  - In the map component, add support for map pins with a description but no title.
+- Improved error messages when a parameter of a sqlpage function is invalid. Error traces used to be truncated, and made it hard to understand the exact cause of the error in some cases. In particular, calls to `sqlpage.fetch` would display an unhelpful error message when the HTTP request definition was invalid.
 
 ## 0.32.1 (2025-01-03)
 

src/webserver/database/sqlpage_functions/function_definition_macro.rs

@@ -66,7 +66,7 @@ macro_rules! sqlpage_functions {
                             let mut iter_params = params.into_iter();
                             $(
                                 let $param_name = <$param_type as FunctionParamType<'_>>::from_args(&mut iter_params)
-                                    .map_err(|e| anyhow!("Parameter {}: {e}", stringify!($param_name)))?;
+                                    .with_context(|| format!("Invalid value for parameter {}", stringify!($param_name)))?;
                             )*
                             if let Some(extraneous_param) = iter_params.next() {
                                 anyhow::bail!("Too many arguments. Remove extra argument {}", as_sql(extraneous_param));