fix pattern handling in regexp_match function (#1065)

datafusion/src/physical_plan/regex_expressions.rs

@@ -47,10 +47,17 @@ macro_rules! downcast_string_arg {
 /// extract a specific group from a string column, using a regular expression
 pub fn regexp_match<T: StringOffsetSizeTrait>(args: &[ArrayRef]) -> Result<ArrayRef> {
     match args.len() {
-        2 => compute::regexp_match(downcast_string_arg!(args[0], "string", T), downcast_string_arg!(args[1], "pattern", T), None)
-        .map_err(DataFusionError::ArrowError),
-        3 => compute::regexp_match(downcast_string_arg!(args[0], "string", T), downcast_string_arg!(args[1], "pattern", T),  Some(downcast_string_arg!(args[1], "flags", T)))
-        .map_err(DataFusionError::ArrowError),
+        2 => {
+            let values = downcast_string_arg!(args[0], "string", T);
+            let regex = downcast_string_arg!(args[1], "pattern", T);
+            compute::regexp_match(values, regex, None).map_err(DataFusionError::ArrowError)
+        }
+        3 => {
+            let values = downcast_string_arg!(args[0], "string", T);
+            let regex = downcast_string_arg!(args[1], "pattern", T);
+            let flags = Some(downcast_string_arg!(args[2], "flags", T));
+            compute::regexp_match(values, regex,  flags).map_err(DataFusionError::ArrowError)
+        }
         other => Err(DataFusionError::Internal(format!(
             "regexp_match was called with {} arguments. It requires at least 2 and at most 3.",
             other
@@ -170,3 +177,58 @@ pub fn regexp_replace<T: StringOffsetSizeTrait>(args: &[ArrayRef]) -> Result<Arr
         ))),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use arrow::array::*;
+
+    #[test]
+    fn test_case_sensitive_regexp_match() {
+        let values = StringArray::from(vec!["abc"; 5]);
+        let patterns =
+            StringArray::from(vec!["^(a)", "^(A)", "(b|d)", "(B|D)", "^(b|c)"]);
+
+        let elem_builder: GenericStringBuilder<i32> = GenericStringBuilder::new(0);
+        let mut expected_builder = ListBuilder::new(elem_builder);
+        expected_builder.values().append_value("a").unwrap();
+        expected_builder.append(true).unwrap();
+        expected_builder.append(false).unwrap();
+        expected_builder.values().append_value("b").unwrap();
+        expected_builder.append(true).unwrap();
+        expected_builder.append(false).unwrap();
+        expected_builder.append(false).unwrap();
+        let expected = expected_builder.finish();
+
+        let re = regexp_match::<i32>(&[Arc::new(values), Arc::new(patterns)]).unwrap();
+
+        assert_eq!(re.as_ref(), &expected);
+    }
+
+    #[test]
+    fn test_case_insensitive_regexp_match() {
+        let values = StringArray::from(vec!["abc"; 5]);
+        let patterns =
+            StringArray::from(vec!["^(a)", "^(A)", "(b|d)", "(B|D)", "^(b|c)"]);
+        let flags = StringArray::from(vec!["i"; 5]);
+
+        let elem_builder: GenericStringBuilder<i32> = GenericStringBuilder::new(0);
+        let mut expected_builder = ListBuilder::new(elem_builder);
+        expected_builder.values().append_value("a").unwrap();
+        expected_builder.append(true).unwrap();
+        expected_builder.values().append_value("a").unwrap();
+        expected_builder.append(true).unwrap();
+        expected_builder.values().append_value("b").unwrap();
+        expected_builder.append(true).unwrap();
+        expected_builder.values().append_value("b").unwrap();
+        expected_builder.append(true).unwrap();
+        expected_builder.append(false).unwrap();
+        let expected = expected_builder.finish();
+
+        let re =
+            regexp_match::<i32>(&[Arc::new(values), Arc::new(patterns), Arc::new(flags)])
+                .unwrap();
+
+        assert_eq!(re.as_ref(), &expected);
+    }
+}