Improve AggregationFuzzer error reporting (#12832)

* Improve AggregationFuzzer error reporting

* simplify

* Update datafusion/core/tests/fuzz_cases/aggregation_fuzzer/fuzzer.rs

* fmt

Author: alamb

datafusion/core/tests/fuzz_cases/aggregate_fuzz.rs

@@ -83,7 +83,7 @@ async fn test_basic_prim_aggr_no_group() {
         .table_name("fuzz_table")
         .build();
 
-    fuzzer.run().await;
+    fuzzer.run().await
 }
 
 /// Fuzz test for `basic prim aggr(sum/sum distinct/max/min/count/avg)` + `group by single int64`

datafusion/core/tests/fuzz_cases/aggregation_fuzzer/fuzzer.rs

@@ -19,6 +19,7 @@ use std::sync::Arc;
 
 use arrow::util::pretty::pretty_format_batches;
 use arrow_array::RecordBatch;
+use datafusion_common::{DataFusionError, Result};
 use rand::{thread_rng, Rng};
 use tokio::task::JoinSet;
 
@@ -132,7 +133,20 @@ struct QueryGroup {
 }
 
 impl AggregationFuzzer {
+    /// Run the fuzzer, printing an error and panicking if any of the tasks fail
     pub async fn run(&self) {
+        let res = self.run_inner().await;
+
+        if let Err(e) = res {
+            // Print the error via `Display` so that it displays nicely (the default `unwrap()`
+            // prints using `Debug` which escapes newlines, and makes multi-line messages
+            // hard to read
+            println!("{e}");
+            panic!("Error!");
+        }
+    }
+
+    async fn run_inner(&self) -> Result<()> {
         let mut join_set = JoinSet::new();
         let mut rng = thread_rng();
 
@@ -157,16 +171,20 @@ impl AggregationFuzzer {
 
             let tasks = self.generate_fuzz_tasks(query_groups).await;
             for task in tasks {
-                join_set.spawn(async move {
-                    task.run().await;
-                });
+                join_set.spawn(async move { task.run().await });
             }
         }
 
         while let Some(join_handle) = join_set.join_next().await {
             // propagate errors
-            join_handle.unwrap();
+            join_handle.map_err(|e| {
+                DataFusionError::Internal(format!(
+                    "AggregationFuzzer task error: {:?}",
+                    e
+                ))
+            })??;
         }
+        Ok(())
     }
 
     async fn generate_fuzz_tasks(
@@ -237,45 +255,53 @@ struct AggregationFuzzTestTask {
 }
 
 impl AggregationFuzzTestTask {
-    async fn run(&self) {
+    async fn run(&self) -> Result<()> {
         let task_result = run_sql(&self.sql, &self.ctx_with_params.ctx)
             .await
-            .expect("should success to run sql");
-        self.check_result(&task_result, &self.expected_result);
+            .map_err(|e| e.context(self.context_error_report()))?;
+        self.check_result(&task_result, &self.expected_result)
     }
 
-    // TODO: maybe we should persist the `expected_result` and `task_result`,
-    // because the readability is not so good if we just print it.
-    fn check_result(&self, task_result: &[RecordBatch], expected_result: &[RecordBatch]) {
-        let result = check_equality_of_batches(task_result, expected_result);
-        if let Err(e) = result {
+    fn check_result(
+        &self,
+        task_result: &[RecordBatch],
+        expected_result: &[RecordBatch],
+    ) -> Result<()> {
+        check_equality_of_batches(task_result, expected_result).map_err(|e| {
             // If we found inconsistent result, we print the test details for reproducing at first
-            println!(
-                "##### AggregationFuzzer error report #####
-                 ### Sql:\n{}\n\
-                 ### Schema:\n{}\n\
-                 ### Session context params:\n{:?}\n\
-                 ### Inconsistent row:\n\
-                 - row_idx:{}\n\
-                 - task_row:{}\n\
-                 - expected_row:{}\n\
-                 ### Task total result:\n{}\n\
-                 ### Expected total result:\n{}\n\
-                 ### Input:\n{}\n\
-                 ",
-                self.sql,
-                self.dataset_ref.batches[0].schema_ref(),
-                self.ctx_with_params.params,
+            let message = format!(
+                "{}\n\
+                     ### Inconsistent row:\n\
+                     - row_idx:{}\n\
+                     - task_row:{}\n\
+                     - expected_row:{}\n\
+                     ### Task total result:\n{}\n\
+                     ### Expected total result:\n{}\n\
+                     ",
+                self.context_error_report(),
                 e.row_idx,
                 e.lhs_row,
                 e.rhs_row,
                 pretty_format_batches(task_result).unwrap(),
                 pretty_format_batches(expected_result).unwrap(),
-                pretty_format_batches(&self.dataset_ref.batches).unwrap(),
             );
+            DataFusionError::Internal(message)
+        })
+    }
 
-            // Then we just panic
-            panic!();
-        }
+    /// Returns a formatted error message
+    fn context_error_report(&self) -> String {
+        format!(
+            "##### AggregationFuzzer error report #####\n\
+               ### Sql:\n{}\n\
+               ### Schema:\n{}\n\
+               ### Session context params:\n{:?}\n\
+               ### Input:\n{}\n\
+                     ",
+            self.sql,
+            self.dataset_ref.batches[0].schema_ref(),
+            self.ctx_with_params.params,
+            pretty_format_batches(&self.dataset_ref.batches).unwrap(),
+        )
     }
 }