Remove defunct column_decltype feature

Author: mlafeldt

crates/duckdb/Cargo.toml

@@ -32,8 +32,6 @@ extensions-full = ["json", "parquet", "vtab-full"]
 buildtime_bindgen = ["libduckdb-sys/buildtime_bindgen"]
 modern-full = ["chrono", "serde_json", "url", "r2d2", "uuid", "polars"]
 polars = ["dep:polars", "dep:polars-arrow"]
-# FIXME: These were added to make clippy happy: these features appear unused and should perhaps be removed
-column_decltype = []
 # Warning: experimental feature
 loadable-extension = ["libduckdb-sys/loadable-extension"]
 

crates/duckdb/src/column.rs

@@ -140,52 +140,12 @@ impl Statement<'_> {
     pub fn column_type(&self, idx: usize) -> DataType {
         self.stmt.column_type(idx)
     }
-
-    /// Returns a slice describing the columns of the result of the query.
-    ///
-    /// If associated DB schema can be altered concurrently, you should make
-    /// sure that current statement has already been stepped once before
-    /// calling this method.
-    #[cfg(feature = "column_decltype")]
-    pub fn columns(&self) -> Vec<Column<'_>> {
-        let n = self.column_count();
-        let mut cols = Vec::with_capacity(n);
-        for i in 0..n {
-            let name = self.column_name_unwrap(i);
-            let slice = self.stmt.column_decltype(i);
-            let decl_type =
-                slice.map(|s| str::from_utf8(s.to_bytes()).expect("Invalid UTF-8 sequence in column declaration"));
-            cols.push(Column { name, decl_type });
-        }
-        cols
-    }
 }
 
 #[cfg(test)]
 mod test {
     use crate::{Connection, Result};
 
-    #[test]
-    #[cfg(feature = "column_decltype")]
-    fn test_columns() -> Result<()> {
-        use super::Column;
-
-        let db = Connection::open_in_memory()?;
-        let query = db.prepare("SELECT * FROM sqlite_master")?;
-        let columns = query.columns();
-        let column_names: Vec<&str> = columns.iter().map(Column::name).collect();
-        assert_eq!(
-            column_names.as_slice(),
-            &["type", "name", "tbl_name", "rootpage", "sql"]
-        );
-        let column_types: Vec<Option<&str>> = columns.iter().map(Column::decl_type).collect();
-        assert_eq!(
-            &column_types[..3],
-            &[Some("VARCHAR"), Some("VARCHAR"), Some("VARCHAR"),]
-        );
-        Ok(())
-    }
-
     #[test]
     fn test_column_name_in_error() -> Result<()> {
         use crate::{types::Type, Error};

crates/duckdb/src/raw_statement.rs

@@ -215,12 +215,6 @@ impl RawStatement {
         self.schema.clone().unwrap()
     }
 
-    #[inline]
-    #[allow(dead_code)]
-    pub fn column_decltype(&self, _idx: usize) -> Option<&CStr> {
-        panic!("not implemented")
-    }
-
     #[inline]
     pub fn column_name(&self, idx: usize) -> Option<&String> {
         if idx >= self.column_count() {