Fix config_namespace macro symbol usage

datafusion/common/src/config.rs

@@ -108,6 +108,7 @@ use crate::{DataFusionError, Result};
 /// ```
 ///
 /// NB: Misplaced commas may result in nonsensical errors
+#[macro_export]
 macro_rules! config_namespace {
     (
         $(#[doc = $struct_d:tt])* // Struct-level documentation attributes
@@ -138,8 +139,8 @@ macro_rules! config_namespace {
             )*
         }
 
-        impl ConfigField for $struct_name {
-            fn set(&mut self, key: &str, value: &str) -> Result<()> {
+        impl $crate::config::ConfigField for $struct_name {
+            fn set(&mut self, key: &str, value: &str) -> $crate::error::Result<()> {
                 let (key, rem) = key.split_once('.').unwrap_or((key, ""));
                 match key {
                     $(
@@ -154,13 +155,13 @@ macro_rules! config_namespace {
                             }
                         },
                     )*
-                    _ => return _config_err!(
+                    _ => return $crate::error::_config_err!(
                         "Config value \"{}\" not found on {}", key, stringify!($struct_name)
                     )
                 }
             }
 
-            fn visit<V: Visit>(&self, v: &mut V, key_prefix: &str, _description: &'static str) {
+            fn visit<V: $crate::config::Visit>(&self, v: &mut V, key_prefix: &str, _description: &'static str) {
                 $(
                     let key = format!(concat!("{}.", stringify!($field_name)), key_prefix);
                     let desc = concat!($($d),*).trim();

datafusion/core/tests/macro_hygiene/mod.rs

@@ -49,3 +49,19 @@ mod record_batch {
         record_batch!(("column_name", Int32, vec![1, 2, 3])).unwrap();
     }
 }
+
+mod config_namespace {
+    // NO other imports!
+    use datafusion_common::config_namespace;
+
+    #[test]
+    fn test_macro() {
+        config_namespace! {
+            /// A config section
+            pub struct Foo {
+                /// Some doc comments
+                pub bar: bool, default = true
+            }
+        }
+    }
+}