Add a hint about expected extension in error message in register_csv,…

datafusion/core/src/execution/context/avro.rs

@@ -46,6 +46,8 @@ impl SessionContext {
         let listing_options = options
             .to_listing_options(&self.copied_config(), self.copied_table_options());
 
+        self.register_type_check(table_path.as_ref(), &listing_options.file_extension)?;
+
         self.register_listing_table(
             table_ref,
             table_path,

datafusion/core/src/execution/context/csv.rs

@@ -62,6 +62,8 @@ impl SessionContext {
         let listing_options = options
             .to_listing_options(&self.copied_config(), self.copied_table_options());
 
+        self.register_type_check(table_path.as_ref(), &listing_options.file_extension)?;
+
         self.register_listing_table(
             table_ref,
             table_path,

datafusion/core/src/execution/context/json.rs

@@ -48,6 +48,8 @@ impl SessionContext {
         let listing_options = options
             .to_listing_options(&self.copied_config(), self.copied_table_options());
 
+        self.register_type_check(table_path.as_ref(), &listing_options.file_extension)?;
+
         self.register_listing_table(
             table_ref,
             table_path,

datafusion/core/src/execution/context/mod.rs

@@ -1379,6 +1379,29 @@ impl SessionContext {
         Ok(())
     }
 
+    fn register_type_check<P: DataFilePaths>(
+        &self,
+        table_paths: P,
+        extension: impl AsRef<str>,
+    ) -> Result<()> {
+        let table_paths = table_paths.to_urls()?;
+        if table_paths.is_empty() {
+            return exec_err!("No table paths were provided");
+        }
+
+        // check if the file extension matches the expected extension
+        let extension = extension.as_ref();
+        for path in &table_paths {
+            let file_path = path.as_str();
+            if !file_path.ends_with(extension) && !path.is_collection() {
+                return exec_err!(
+                    "File path '{file_path}' does not match the expected extension '{extension}'"
+                );
+            }
+        }
+        Ok(())
+    }
+
     /// Registers an Arrow file as a table that can be referenced from
     /// SQL statements executed against this context.
     pub async fn register_arrow(

datafusion/core/src/execution/context/parquet.rs

@@ -50,6 +50,8 @@ impl SessionContext {
         let listing_options = options
             .to_listing_options(&self.copied_config(), self.copied_table_options());
 
+        self.register_type_check(table_path.as_ref(), &listing_options.file_extension)?;
+
         self.register_listing_table(
             table_ref,
             table_path,

datafusion/core/tests/dataframe/mod.rs

@@ -54,8 +54,9 @@ use datafusion::error::Result;
 use datafusion::execution::context::SessionContext;
 use datafusion::execution::session_state::SessionStateBuilder;
 use datafusion::logical_expr::{ColumnarValue, Volatility};
-use datafusion::prelude::{CsvReadOptions, ParquetReadOptions};
-use datafusion::prelude::{JoinType, NdJsonReadOptions};
+use datafusion::prelude::{
+    AvroReadOptions, CsvReadOptions, JoinType, NdJsonReadOptions, ParquetReadOptions,
+};
 use datafusion::test_util::{
     parquet_test_data, populate_csv_partitions, register_aggregate_csv, test_table,
     test_table_with_name,
@@ -5121,3 +5122,63 @@ async fn test_alias_nested() -> Result<()> {
     );
     Ok(())
 }
+
+#[tokio::test]
+async fn register_non_json_file() {
+    let ctx = SessionContext::new();
+    let err = ctx
+        .register_json(
+            "data",
+            "tests/data/test_binary.parquet",
+            NdJsonReadOptions::default(),
+        )
+        .await;
+    assert_contains!(
+        err.unwrap_err().to_string(),
+        "test_binary.parquet' does not match the expected extension '.json'"
+    );
+}
+
+#[tokio::test]
+async fn register_non_csv_file() {
+    let ctx = SessionContext::new();
+    let err = ctx
+        .register_csv(
+            "data",
+            "tests/data/test_binary.parquet",
+            CsvReadOptions::default(),
+        )
+        .await;
+    assert_contains!(
+        err.unwrap_err().to_string(),
+        "test_binary.parquet' does not match the expected extension '.csv'"
+    );
+}
+
+#[tokio::test]
+async fn register_non_avro_file() {
+    let ctx = SessionContext::new();
+    let err = ctx
+        .register_avro(
+            "data",
+            "tests/data/test_binary.parquet",
+            AvroReadOptions::default(),
+        )
+        .await;
+    assert_contains!(
+        err.unwrap_err().to_string(),
+        "test_binary.parquet' does not match the expected extension '.avro'"
+    );
+}
+
+#[tokio::test]
+async fn register_non_parquet_file() {
+    let ctx = SessionContext::new();
+    let err = ctx
+        .register_parquet("data", "tests/data/1.json", ParquetReadOptions::default())
+        .await;
+    assert_contains!(
+        err.unwrap_err().to_string(),
+        "1.json' does not match the expected extension '.parquet'"
+    );
+}