Add DataFusionError::Collection to return multiple DataFusionErrors

datafusion/common/src/error.rs

@@ -20,6 +20,7 @@
 use std::backtrace::{Backtrace, BacktraceStatus};
 
 use std::borrow::Cow;
+use std::collections::VecDeque;
 use std::error::Error;
 use std::fmt::{Display, Formatter};
 use std::io;
@@ -136,6 +137,13 @@ pub enum DataFusionError {
     /// human-readable messages, and locations in the source query that relate
     /// to the error in some way.
     Diagnostic(Box<Diagnostic>, Box<DataFusionError>),
+    /// A collection of one or more [`DataFusionError`]. Useful in cases where
+    /// DataFusion can recover from an erroneous state, and produce more errors
+    /// before terminating. e.g. when planning a SELECT clause, DataFusion can
+    /// synchronize to the next `SelectItem` if the previous one had errors. The
+    /// end result is that the user can see errors about all `SelectItem`,
+    /// instead of just the first one.
+    Collection(Vec<DataFusionError>),
     /// A [`DataFusionError`] which shares an underlying [`DataFusionError`].
     ///
     /// This is useful when the same underlying [`DataFusionError`] is passed
@@ -360,6 +368,14 @@ impl Error for DataFusionError {
             DataFusionError::Context(_, e) => Some(e.as_ref()),
             DataFusionError::Substrait(_) => None,
             DataFusionError::Diagnostic(_, e) => Some(e.as_ref()),
+            // Can't really make a Collection fit into the mold of "an error has
+            // at most one source", but returning the first one is probably good
+            // idea. Especially since `DataFusionError::Collection` is mostly
+            // meant for consumption by the end user, so shouldn't interfere
+            // with programmatic usage too much. Plus, having 1 or 5 errors
+            // doesn't really change the fact that the query is invalid and
+            // can't be executed.
+            DataFusionError::Collection(errs) => errs.first().map(|e| e as &dyn Error),
             DataFusionError::Shared(e) => Some(e.as_ref()),
         }
     }
@@ -463,18 +479,27 @@ impl DataFusionError {
             DataFusionError::ObjectStore(_) => "Object Store error: ",
             DataFusionError::IoError(_) => "IO error: ",
             DataFusionError::SQL(_, _) => "SQL error: ",
-            DataFusionError::NotImplemented(_) => "This feature is not implemented: ",
+            DataFusionError::NotImplemented(_) => {
+                "This feature is not implemented: "
+            }
             DataFusionError::Internal(_) => "Internal error: ",
             DataFusionError::Plan(_) => "Error during planning: ",
-            DataFusionError::Configuration(_) => "Invalid or Unsupported Configuration: ",
+            DataFusionError::Configuration(_) => {
+                "Invalid or Unsupported Configuration: "
+            }
             DataFusionError::SchemaError(_, _) => "Schema error: ",
             DataFusionError::Execution(_) => "Execution error: ",
             DataFusionError::ExecutionJoin(_) => "ExecutionJoin error: ",
-            DataFusionError::ResourcesExhausted(_) => "Resources exhausted: ",
+            DataFusionError::ResourcesExhausted(_) => {
+                "Resources exhausted: "
+            }
             DataFusionError::External(_) => "External error: ",
             DataFusionError::Context(_, _) => "",
             DataFusionError::Substrait(_) => "Substrait error: ",
             DataFusionError::Diagnostic(_, _) => "",
+            DataFusionError::Collection(errs) => {
+                errs.first().expect("cannot construct DataFusionError::Collection with 0 errors, but got one such case").error_prefix()
+            }
             DataFusionError::Shared(_) => "",
         }
     }
@@ -517,6 +542,13 @@ impl DataFusionError {
             }
             DataFusionError::Substrait(ref desc) => Cow::Owned(desc.to_string()),
             DataFusionError::Diagnostic(_, ref err) => Cow::Owned(err.to_string()),
+            // Returning the message of the first error is probably fine enough,
+            // and makes `DataFusionError::Collection` a transparent wrapped,
+            // unless the end user explicitly calls `DataFusionError::iter`.
+            DataFusionError::Collection(ref errs) => errs
+                .first()
+                .expect("cannot construct DataFusionError::Collection with 0 errors")
+                .message(),
             DataFusionError::Shared(ref desc) => Cow::Owned(desc.to_string()),
         }
     }
@@ -569,6 +601,63 @@ impl DataFusionError {
 
         DiagnosticsIterator { head: self }.next()
     }
+
+    /// Sometimes DataFusion is able to collect multiple errors in a SQL query
+    /// before terminating, e.g. across different expressions in a SELECT
+    /// statements or different sides of a UNION. This method returns an
+    /// iterator over all the errors in the collection.
+    ///
+    /// For this to work, the top-level error must be a
+    /// `DataFusionError::Collection`, not something that contains it.
+    pub fn iter(&self) -> impl Iterator<Item = &DataFusionError> {
+        struct ErrorIterator<'a> {
+            queue: VecDeque<&'a DataFusionError>,
+        }
+
+        impl<'a> Iterator for ErrorIterator<'a> {
+            type Item = &'a DataFusionError;
+
+            fn next(&mut self) -> Option<Self::Item> {
+                loop {
+                    let popped = self.queue.pop_front()?;
+                    match popped {
+                        DataFusionError::Collection(errs) => self.queue.extend(errs),
+                        _ => return Some(popped),
+                    }
+                }
+            }
+        }
+
+        let mut queue = VecDeque::new();
+        queue.push_back(self);
+        ErrorIterator { queue }
+    }
+}
+
+pub struct DataFusionErrorBuilder(Vec<DataFusionError>);
+
+impl DataFusionErrorBuilder {
+    pub fn new() -> Self {
+        Self(Vec::new())
+    }
+
+    pub fn add_error(&mut self, error: DataFusionError) {
+        self.0.push(error);
+    }
+
+    pub fn error_or<T>(self, ok: T) -> Result<T, DataFusionError> {
+        match self.0.len() {
+            0 => Ok(ok),
+            1 => Err(self.0.into_iter().next().expect("length matched 1")),
+            _ => Err(DataFusionError::Collection(self.0)),
+        }
+    }
+}
+
+impl Default for DataFusionErrorBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
 }
 
 /// Unwrap an `Option` if possible. Otherwise return an `DataFusionError::Internal`.
@@ -954,4 +1043,20 @@ mod test {
         assert_eq!(e.strip_backtrace(), exp.strip_backtrace());
         assert_eq!(std::mem::discriminant(e), std::mem::discriminant(&exp),)
     }
+
+    #[test]
+    fn test_iter() {
+        let err = DataFusionError::Collection(vec![
+            DataFusionError::Plan("a".to_string()),
+            DataFusionError::Collection(vec![
+                DataFusionError::Plan("b".to_string()),
+                DataFusionError::Plan("c".to_string()),
+            ]),
+        ]);
+        let errs = err.iter().collect::<Vec<_>>();
+        assert_eq!(errs.len(), 3);
+        assert_eq!(errs[0].strip_backtrace(), "Error during planning: a");
+        assert_eq!(errs[1].strip_backtrace(), "Error during planning: b");
+        assert_eq!(errs[2].strip_backtrace(), "Error during planning: c");
+    }
 }

datafusion/expr/src/type_coercion/functions.rs

@@ -261,8 +261,9 @@ fn get_valid_types_with_scalar_udf(
         TypeSignature::UserDefined => match func.coerce_types(current_types) {
             Ok(coerced_types) => Ok(vec![coerced_types]),
             Err(e) => exec_err!(
-                "Function '{}' user-defined coercion failed with {e:?}",
-                func.name()
+                "Function '{}' user-defined coercion failed with {:?}",
+                func.name(),
+                e.strip_backtrace()
             ),
         },
         TypeSignature::OneOf(signatures) => {
@@ -304,8 +305,9 @@ fn get_valid_types_with_aggregate_udf(
             Ok(coerced_types) => vec![coerced_types],
             Err(e) => {
                 return exec_err!(
-                    "Function '{}' user-defined coercion failed with {e:?}",
-                    func.name()
+                    "Function '{}' user-defined coercion failed with {:?}",
+                    func.name(),
+                    e.strip_backtrace()
                 )
             }
         },
@@ -332,8 +334,9 @@ fn get_valid_types_with_window_udf(
             Ok(coerced_types) => vec![coerced_types],
             Err(e) => {
                 return exec_err!(
-                    "Function '{}' user-defined coercion failed with {e:?}",
-                    func.name()
+                    "Function '{}' user-defined coercion failed with {:?}",
+                    func.name(),
+                    e.strip_backtrace()
                 )
             }
         },

datafusion/sql/src/select.rs

@@ -25,6 +25,7 @@ use crate::utils::{
     CheckColumnsSatisfyExprsPurpose,
 };
 
+use datafusion_common::error::DataFusionErrorBuilder;
 use datafusion_common::tree_node::{TreeNode, TreeNodeRecursion};
 use datafusion_common::{not_impl_err, plan_err, Result};
 use datafusion_common::{RecursionUnnestOption, UnnestOptions};
@@ -574,10 +575,15 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
         empty_from: bool,
         planner_context: &mut PlannerContext,
     ) -> Result<Vec<Expr>> {
-        projection
-            .into_iter()
-            .map(|expr| self.sql_select_to_rex(expr, plan, empty_from, planner_context))
-            .collect::<Result<Vec<Expr>>>()
+        let mut prepared_select_exprs = vec![];
+        let mut error_builder = DataFusionErrorBuilder::new();
+        for expr in projection {
+            match self.sql_select_to_rex(expr, plan, empty_from, planner_context) {
+                Ok(expr) => prepared_select_exprs.push(expr),
+                Err(err) => error_builder.add_error(err),
+            }
+        }
+        error_builder.error_or(prepared_select_exprs)
     }
 
     /// Generate a relational expression from a select SQL expression

datafusion/sql/src/set_expr.rs

@@ -16,7 +16,9 @@
 // under the License.
 
 use crate::planner::{ContextProvider, PlannerContext, SqlToRel};
-use datafusion_common::{not_impl_err, plan_err, Diagnostic, Result, Span};
+use datafusion_common::{
+    not_impl_err, plan_err, DataFusionError, Diagnostic, Result, Span,
+};
 use datafusion_expr::{LogicalPlan, LogicalPlanBuilder};
 use sqlparser::ast::{SetExpr, SetOperator, SetQuantifier, Spanned};
 
@@ -39,8 +41,19 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
             } => {
                 let left_span = Span::try_from_sqlparser_span(left.span());
                 let right_span = Span::try_from_sqlparser_span(right.span());
-                let left_plan = self.set_expr_to_plan(*left, planner_context)?;
-                let right_plan = self.set_expr_to_plan(*right, planner_context)?;
+                let left_plan = self.set_expr_to_plan(*left, planner_context);
+                let right_plan = self.set_expr_to_plan(*right, planner_context);
+                let (left_plan, right_plan) = match (left_plan, right_plan) {
+                    (Ok(left_plan), Ok(right_plan)) => (left_plan, right_plan),
+                    (Err(left_err), Err(right_err)) => {
+                        return Err(DataFusionError::Collection(vec![
+                            left_err, right_err,
+                        ]));
+                    }
+                    (Err(err), _) | (_, Err(err)) => {
+                        return Err(err);
+                    }
+                };
                 self.validate_set_expr_num_of_columns(
                     op,
                     left_span,
@@ -49,6 +62,7 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
                     &right_plan,
                     set_expr_span,
                 )?;
+
                 self.set_operation_to_plan(op, left_plan, right_plan, set_quantifier)
             }
             SetExpr::Query(q) => self.query_to_plan(*q, planner_context),

datafusion/sql/tests/cases/collection.rs

@@ -0,0 +1,59 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use datafusion_common::{assert_contains, DataFusionError};
+use datafusion_sql::planner::SqlToRel;
+use sqlparser::{dialect::GenericDialect, parser::Parser};
+
+use crate::{MockContextProvider, MockSessionState};
+
+fn do_query(sql: &'static str) -> DataFusionError {
+    let dialect = GenericDialect {};
+    let statement = Parser::new(&dialect)
+        .try_with_sql(sql)
+        .expect("unable to create parser")
+        .parse_statement()
+        .expect("unable to parse query");
+    let state = MockSessionState::default();
+    let context = MockContextProvider { state };
+    let sql_to_rel = SqlToRel::new(&context);
+    sql_to_rel
+        .sql_statement_to_plan(statement)
+        .expect_err("expected error")
+}
+
+#[test]
+fn test_collect_select_items() {
+    let query = "SELECT first_namex, last_namex FROM person";
+    let error = do_query(query);
+    let errors = error.iter().collect::<Vec<_>>();
+    assert_eq!(errors.len(), 2);
+    assert!(errors[0]
+        .to_string()
+        .contains("No field named first_namex."));
+    assert_contains!(errors[1].to_string(), "No field named last_namex.");
+}
+
+#[test]
+fn test_collect_set_exprs() {
+    let query = "SELECT first_namex FROM person UNION ALL SELECT last_namex FROM person";
+    let error = do_query(query);
+    let errors = error.iter().collect::<Vec<_>>();
+    assert_eq!(errors.len(), 2);
+    assert_contains!(errors[0].to_string(), "No field named first_namex.");
+    assert_contains!(errors[1].to_string(), "No field named last_namex.");
+}

datafusion/sql/tests/cases/mod.rs

@@ -15,5 +15,6 @@
 // specific language governing permissions and limitations
 // under the License.
 
+mod collection;
 mod diagnostic;
 mod plan_to_sql;

datafusion/sql/tests/sql_integration.rs

@@ -4422,10 +4422,17 @@ fn plan_create_index() {
     }
 }
 
-fn assert_field_not_found(err: DataFusionError, name: &str) {
-    let err = match err {
-        DataFusionError::Diagnostic(_, err) => *err,
-        err => err,
+fn assert_field_not_found(mut err: DataFusionError, name: &str) {
+    let err = loop {
+        match err {
+            DataFusionError::Diagnostic(_, wrapped_err) => {
+                err = *wrapped_err;
+            }
+            DataFusionError::Collection(errs) => {
+                err = errs.into_iter().next().unwrap();
+            }
+            err => break err,
+        }
     };
     match err {
         DataFusionError::SchemaError { .. } => {

datafusion/sqllogictest/src/engines/datafusion_engine/error.rs

@@ -30,7 +30,7 @@ pub enum DFSqlLogicTestError {
     #[error("SqlLogicTest error(from sqllogictest-rs crate): {0}")]
     SqlLogicTest(#[from] TestError),
     /// Error from datafusion
-    #[error("DataFusion error: {0}")]
+    #[error("DataFusion error: {}", .0.strip_backtrace())]
     DataFusion(#[from] DataFusionError),
     /// Error returned when SQL is syntactically incorrect.
     #[error("SQL Parser error: {0}")]

datafusion/sqllogictest/test_files/errors.slt

@@ -148,7 +148,7 @@ SELECT
 query error DataFusion error: Arrow error: Cast error: Cannot cast string 'foo' to value of Int64 type
 create table foo as values (1), ('foo');
 
-query error No function matches
+query error user-defined coercion failed
 select 1 group by substr('');
 
 # Error in filter should be reported