ARROW-11790: [Rust][DataFusion] RFC: Change builder signatures to take Vec<Expr> rather than &[Expr]

rust/benchmarks/src/bin/tpch.rs

@@ -1636,7 +1636,7 @@ mod tests {
                 .file_extension(".out");
             let df = ctx.read_csv(&format!("{}/answers/q{}.out", path, n), options)?;
             let df = df.select(
-                &get_answer_schema(n)
+                get_answer_schema(n)
                     .fields()
                     .iter()
                     .map(|field| {

rust/datafusion/examples/simple_udf.rs

@@ -133,7 +133,7 @@ async fn main() -> Result<()> {
     let expr1 = pow.call(vec![col("a"), col("b")]);
 
     // equivalent to `'SELECT pow(a, b), pow(a, b) AS pow1 FROM t'`
-    let df = df.select(&[
+    let df = df.select(vec![
         expr,
         // alias so that they have different column names
         expr1.alias("pow1"),

rust/datafusion/src/dataframe.rs

@@ -75,11 +75,11 @@ pub trait DataFrame: Send + Sync {
     /// # fn main() -> Result<()> {
     /// let mut ctx = ExecutionContext::new();
     /// let df = ctx.read_csv("tests/example.csv", CsvReadOptions::new())?;
-    /// let df = df.select(&[col("a") * col("b"), col("c")])?;
+    /// let df = df.select(vec![col("a") * col("b"), col("c")])?;
     /// # Ok(())
     /// # }
     /// ```
-    fn select(&self, expr: &[Expr]) -> Result<Arc<dyn DataFrame>>;
+    fn select(&self, expr: Vec<Expr>) -> Result<Arc<dyn DataFrame>>;
 
     /// Filter a DataFrame to only include rows that match the specified filter expression.
     ///
@@ -157,7 +157,7 @@ pub trait DataFrame: Send + Sync {
     /// let mut ctx = ExecutionContext::new();
     /// let left = ctx.read_csv("tests/example.csv", CsvReadOptions::new())?;
     /// let right = ctx.read_csv("tests/example.csv", CsvReadOptions::new())?
-    ///   .select(&[
+    ///   .select(vec![
     ///     col("a").alias("a2"),
     ///     col("b").alias("b2"),
     ///     col("c").alias("c2")])?;

rust/datafusion/src/execution/context.rs

@@ -834,7 +834,7 @@ mod tests {
 
         let table = ctx.table("test")?;
         let logical_plan = LogicalPlanBuilder::from(&table.to_logical_plan())
-            .project(&[col("c2")])?
+            .project(vec![col("c2")])?
             .build()?;
 
         let optimized_plan = ctx.optimize(&logical_plan)?;
@@ -886,7 +886,7 @@ mod tests {
         assert_eq!(schema.field_with_name("c1")?.is_nullable(), false);
 
         let plan = LogicalPlanBuilder::scan_empty("", schema.as_ref(), None)?
-            .project(&[col("c1")])?
+            .project(vec![col("c1")])?
             .build()?;
 
         let plan = ctx.optimize(&plan)?;
@@ -917,7 +917,7 @@ mod tests {
         )?]];
 
         let plan = LogicalPlanBuilder::scan_memory(partitions, schema, None)?
-            .project(&[col("b")])?
+            .project(vec![col("b")])?
             .build()?;
         assert_fields_eq(&plan, vec!["b"]);
 
@@ -1548,7 +1548,7 @@ mod tests {
 
         let plan = LogicalPlanBuilder::scan_empty("", schema.as_ref(), None)?
             .aggregate(&[col("c1")], &[sum(col("c2"))])?
-            .project(&[col("c1"), col("SUM(c2)").alias("total_salary")])?
+            .project(vec![col("c1"), col("SUM(c2)").alias("total_salary")])?
             .build()?;
 
         let plan = ctx.optimize(&plan)?;
@@ -1773,7 +1773,7 @@ mod tests {
         let t = ctx.table("t")?;
 
         let plan = LogicalPlanBuilder::from(&t.to_logical_plan())
-            .project(&[
+            .project(vec![
                 col("a"),
                 col("b"),
                 ctx.udf("my_add")?.call(vec![col("a"), col("b")]),

rust/datafusion/src/execution/dataframe_impl.rs

@@ -58,11 +58,11 @@ impl DataFrame for DataFrameImpl {
             .map(|name| self.plan.schema().field_with_unqualified_name(name))
             .collect::<Result<Vec<_>>>()?;
         let expr: Vec<Expr> = fields.iter().map(|f| col(f.name())).collect();
-        self.select(&expr)
+        self.select(expr)
     }
 
     /// Create a projection based on arbitrary expressions
-    fn select(&self, expr_list: &[Expr]) -> Result<Arc<dyn DataFrame>> {
+    fn select(&self, expr_list: Vec<Expr>) -> Result<Arc<dyn DataFrame>> {
         let plan = LogicalPlanBuilder::from(&self.plan)
             .project(expr_list)?
             .build()?;
@@ -197,7 +197,7 @@ mod tests {
     fn select_expr() -> Result<()> {
         // build plan using Table API
         let t = test_table()?;
-        let t2 = t.select(&[col("c1"), col("c2"), col("c11")])?;
+        let t2 = t.select(vec![col("c1"), col("c2"), col("c11")])?;
         let plan = t2.to_logical_plan();
 
         // build query using SQL
@@ -315,7 +315,7 @@ mod tests {
 
         let f = df.registry();
 
-        let df = df.select(&[f.udf("my_fn")?.call(vec![col("c12")])])?;
+        let df = df.select(vec![f.udf("my_fn")?.call(vec![col("c12")])])?;
         let plan = df.to_logical_plan();
 
         // build query using SQL

rust/datafusion/src/logical_plan/builder.rs

@@ -132,16 +132,19 @@ impl LogicalPlanBuilder {
     /// This function errors under any of the following conditions:
     /// * Two or more expressions have the same name
     /// * An invalid expression is used (e.g. a `sort` expression)
-    pub fn project(&self, expr: &[Expr]) -> Result<Self> {
+    pub fn project(&self, expr: Vec<Expr>) -> Result<Self> {
         let input_schema = self.plan.schema();
         let mut projected_expr = vec![];
-        (0..expr.len()).for_each(|i| match &expr[i] {
-            Expr::Wildcard => {
-                (0..input_schema.fields().len())
-                    .for_each(|i| projected_expr.push(col(input_schema.field(i).name())));
-            }
-            _ => projected_expr.push(expr[i].clone()),
-        });
+        for e in expr {
+            match e {
+                Expr::Wildcard => {
+                    (0..input_schema.fields().len()).for_each(|i| {
+                        projected_expr.push(col(input_schema.field(i).name()))
+                    });
+                }
+                _ => projected_expr.push(e),
+            };
+        }
 
         validate_unique_names("Projections", &projected_expr, input_schema)?;
 
@@ -352,7 +355,7 @@ mod tests {
             Some(vec![0, 3]),
         )?
         .filter(col("state").eq(lit("CO")))?
-        .project(&[col("id")])?
+        .project(vec![col("id")])?
         .build()?;
 
         let expected = "Projection: #id\
@@ -372,7 +375,7 @@ mod tests {
             Some(vec![3, 4]),
         )?
         .aggregate(&[col("state")], &[sum(col("salary")).alias("total_salary")])?
-        .project(&[col("state"), col("total_salary")])?
+        .project(vec![col("state"), col("total_salary")])?
         .build()?;
 
         let expected = "Projection: #state, #total_salary\
@@ -421,7 +424,7 @@ mod tests {
             Some(vec![0, 3]),
         )?
         // two columns with the same name => error
-        .project(&[col("id"), col("first_name").alias("id")]);
+        .project(vec![col("id"), col("first_name").alias("id")]);
 
         match plan {
             Err(DataFusionError::Plan(e)) => {

rust/datafusion/src/logical_plan/plan.rs

@@ -762,7 +762,7 @@ mod tests {
         .unwrap()
         .filter(col("state").eq(lit("CO")))
         .unwrap()
-        .project(&[col("id")])
+        .project(vec![col("id")])
         .unwrap()
         .build()
         .unwrap()
@@ -1063,7 +1063,7 @@ mod tests {
             .unwrap()
             .filter(col("state").eq(lit("CO")))
             .unwrap()
-            .project(&[col("id")])
+            .project(vec![col("id")])
             .unwrap()
             .build()
             .unwrap()

rust/datafusion/src/optimizer/constant_folding.rs

@@ -468,7 +468,7 @@ mod tests {
         let plan = LogicalPlanBuilder::from(&table_scan)
             .filter(col("b").eq(lit(true)))?
             .filter(col("c").eq(lit(false)))?
-            .project(&[col("a")])?
+            .project(vec![col("a")])?
             .build()?;
 
         let expected = "\
@@ -488,7 +488,7 @@ mod tests {
             .filter(col("b").not_eq(lit(true)))?
             .filter(col("c").not_eq(lit(false)))?
             .limit(1)?
-            .project(&[col("a")])?
+            .project(vec![col("a")])?
             .build()?;
 
         let expected = "\
@@ -507,7 +507,7 @@ mod tests {
         let table_scan = test_table_scan()?;
         let plan = LogicalPlanBuilder::from(&table_scan)
             .filter(col("b").not_eq(lit(true)).and(col("c").eq(lit(true))))?
-            .project(&[col("a")])?
+            .project(vec![col("a")])?
             .build()?;
 
         let expected = "\
@@ -524,7 +524,7 @@ mod tests {
         let table_scan = test_table_scan()?;
         let plan = LogicalPlanBuilder::from(&table_scan)
             .filter(col("b").not_eq(lit(true)).or(col("c").eq(lit(false))))?
-            .project(&[col("a")])?
+            .project(vec![col("a")])?
             .build()?;
 
         let expected = "\
@@ -541,7 +541,7 @@ mod tests {
         let table_scan = test_table_scan()?;
         let plan = LogicalPlanBuilder::from(&table_scan)
             .filter(col("b").eq(lit(false)).not())?
-            .project(&[col("a")])?
+            .project(vec![col("a")])?
             .build()?;
 
         let expected = "\
@@ -557,7 +557,7 @@ mod tests {
     fn optimize_plan_support_projection() -> Result<()> {
         let table_scan = test_table_scan()?;
         let plan = LogicalPlanBuilder::from(&table_scan)
-            .project(&[col("a"), col("d"), col("b").eq(lit(false))])?
+            .project(vec![col("a"), col("d"), col("b").eq(lit(false))])?
             .build()?;
 
         let expected = "\
@@ -572,7 +572,7 @@ mod tests {
     fn optimize_plan_support_aggregate() -> Result<()> {
         let table_scan = test_table_scan()?;
         let plan = LogicalPlanBuilder::from(&table_scan)
-            .project(&[col("a"), col("c"), col("b")])?
+            .project(vec![col("a"), col("c"), col("b")])?
             .aggregate(
                 &[col("a"), col("c")],
                 &[max(col("b").eq(lit(true))), min(col("b"))],