From 4fd4136d500c55d19c29ad5e89903afc58d43a97 Mon Sep 17 00:00:00 2001
From: Mathspy <mathspy257@gmail.com>
Date: Tue, 14 Jun 2022 00:04:29 -0400
Subject: [PATCH] Should we keep old semantics of `uniq` command? (#5761)

* Update uniq tests with less surprising output

* Remove original nushell surprising semantics
---
 crates/nu-command/src/filters/uniq.rs | 33 ++++++++++++---------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/crates/nu-command/src/filters/uniq.rs b/crates/nu-command/src/filters/uniq.rs
index a165748ef2..7c519032cc 100644
--- a/crates/nu-command/src/filters/uniq.rs
+++ b/crates/nu-command/src/filters/uniq.rs
@@ -2,9 +2,7 @@ use std::collections::VecDeque;
 
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
-use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Span, Value,
-};
+use nu_protocol::{Category, Example, IntoPipelineData, PipelineData, Signature, Span, Value};
 
 #[derive(Clone)]
 pub struct Uniq;
@@ -62,12 +60,18 @@ impl Command for Uniq {
             Example {
                 description: "Only print duplicate lines, one for each group",
                 example: "[1 2 2] | uniq -d",
-                result: Some(Value::test_int(2)),
+                result: Some(Value::List {
+                    vals: vec![Value::test_int(2)],
+                    span: Span::test_data(),
+                }),
             },
             Example {
                 description: "Only print unique lines lines",
                 example: "[1 2 2] | uniq -u",
-                result: Some(Value::test_int(1)),
+                result: Some(Value::List {
+                    vals: vec![Value::test_int(1)],
+                    span: Span::test_data(),
+                }),
             },
             Example {
                 description: "Ignore differences in case when comparing",
@@ -182,21 +186,12 @@ fn uniq(
         }
     }
 
-    // keeps the original Nushell semantics
-    if values_vec_deque.len() == 1 {
-        if let Some(x) = values_vec_deque.pop_front() {
-            Ok(x.into_pipeline_data().set_metadata(metadata))
-        } else {
-            Err(ShellError::NushellFailed("No input given...".to_string()))
-        }
-    } else {
-        Ok(Value::List {
-            vals: values_vec_deque.into_iter().collect(),
-            span: head,
-        }
-        .into_pipeline_data()
-        .set_metadata(metadata))
+    Ok(Value::List {
+        vals: values_vec_deque.into_iter().collect(),
+        span: head,
     }
+    .into_pipeline_data()
+    .set_metadata(metadata))
 }
 
 #[cfg(test)]