fixing tests3 - account is reserved when accounting is selected for that table

common/src/system_column.rs

@@ -5,9 +5,9 @@
 //! leaves the server. A user column is stored under its ordinal and shown only
 //! under its alias, so an unmapped name at the public boundary is a leak; these
 //! have no alias to hide behind, because the server -- not the user -- chose
-//! their names. Anything asking "is this name public?" or "may a user claim
-//! this name?" is asking about this list, so the list lives here once and the
-//! `CREATE TABLE` fragments that make it true live next to it.
+//! their names. The list lives here once and the `CREATE TABLE` fragments that
+//! make it true live next to it. Alias validation may still be conditional: the
+//! virtual `account` API name conflicts only on ACCOUNTING-enabled tables.
 
 /// A column every managed table carries, named the same in Postgres and in the
 /// public API.
@@ -85,8 +85,9 @@ pub fn system_column_names() -> impl Iterator<Item = &'static str> {
         .chain(std::iter::once(ACCOUNT_REFERENCE_COLUMN))
 }
 
-/// Whether `name` is a system column: a name that is safe to show a client
-/// as-is, and that a user may not claim for a column alias or a table.
+/// Whether `name` belongs to the system column vocabulary and is safe to show
+/// to a client as-is. Whether a user may claim a virtual API name as an alias
+/// is decided with the table's capabilities in scope.
 pub fn is_system_column(name: &str) -> bool {
     name == ACCOUNT_API_COLUMN || system_column_names().any(|system_name| system_name == name)
 }
@@ -115,7 +116,7 @@ mod tests {
     }
 
     #[test]
-    fn a_conditional_column_is_reserved_on_every_table() {
+    fn conditional_system_names_are_recognized() {
         assert!(is_system_column(ACCOUNT_REFERENCE_COLUMN));
         assert!(is_system_column(ACCOUNT_API_COLUMN));
     }