Resolves #750 (#1164)

Pick now produces an error when none of the columns are found

src/commands/pick.rs

@@ -2,8 +2,9 @@ use crate::commands::WholeStreamCommand;
 use crate::context::CommandRegistry;
 use crate::data::base::select_fields;
 use crate::prelude::*;
+use futures_util::pin_mut;
 use nu_errors::ShellError;
-use nu_protocol::{Signature, SyntaxShape};
+use nu_protocol::{Primitive, ReturnSuccess, ReturnValue, Signature, SyntaxShape, UntaggedValue};
 use nu_source::Tagged;
 
 #[derive(Deserialize)]
@@ -49,9 +50,33 @@ fn pick(
 
     let fields: Vec<_> = fields.iter().map(|f| f.item.clone()).collect();
 
-    let objects = input
+    let stream = async_stream! {
-        .values
+        let values = input.values;
-        .map(move |value| select_fields(&value, &fields, value.tag.clone()));
+        pin_mut!(values);
 
-    Ok(objects.from_input_stream())
+        let mut empty = true;
+
+        while let Some(value) = values.next().await {
+            let new_value = select_fields(&value, &fields, value.tag.clone());
+
+            if let UntaggedValue::Row(dict) = &new_value.value {
+                if dict
+                    .entries
+                    .values()
+                    .any(|v| v.value != UntaggedValue::Primitive(Primitive::Nothing))
+                {
+                    empty = false;
+                    yield ReturnSuccess::value(new_value);
+                }
+            }
+        }
+
+        if empty {
+            yield Err(ShellError::labeled_error("None of the columns were found in the input", "could not find columns given", name));
+        }
+    };
+
+    let stream: BoxStream<'static, ReturnValue> = stream.boxed();
+
+    Ok(stream.to_output_stream())
 }