Set the default min version when min_duckdb_version is not specified (#473)

Author: yutannihilation

crates/duckdb-loadable-macros/src/lib.rs

@@ -10,6 +10,8 @@ use darling::{ast::NestedMeta, Error, FromMeta};
 
 use std::env;
 
+const DEFAULT_DUCKDB_VERSION: &str = "v1.2.0";
+
 /// For parsing the arguments to the duckdb_entrypoint_c_api macro
 #[derive(Debug, FromMeta)]
 struct CEntryPointMacroArgs {
@@ -40,9 +42,10 @@ pub fn duckdb_entrypoint_c_api(attr: TokenStream, item: TokenStream) -> TokenStr
     };
 
     // Set the minimum duckdb version (dev by default)
-    let minimum_duckdb_version = match args.min_duckdb_version {
-        Some(i) => i,
-        None => env::var("DUCKDB_EXTENSION_MIN_DUCKDB_VERSION").expect("Please either set env var DUCKDB_EXTENSION_MIN_DUCKDB_VERSION or pass it as an argument to the proc macro").to_string()
+    let minimum_duckdb_version = match (args.min_duckdb_version, env::var("DUCKDB_EXTENSION_MIN_DUCKDB_VERSION")) {
+        (Some(i), _) => i,
+        (None, Ok(i)) => i.to_string(),
+        _ => DEFAULT_DUCKDB_VERSION.to_string(),
     };
 
     let extension_name = match (args.ext_name, env::var("DUCKDB_EXTENSION_NAME")) {