From 2dd6824e7628d9d3fad77ed44d57654cb45ef6d4 Mon Sep 17 00:00:00 2001
From: Michael Debertol <michael.debertol@gmail.com>
Date: Sun, 6 Jun 2021 11:29:32 +0200
Subject: [PATCH] sort: never use a bigger buffer than requested

A min buffer size of 8KB makes sense in practice, but decreases testability.
---
 src/uu/sort/src/ext_sort.rs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/uu/sort/src/ext_sort.rs b/src/uu/sort/src/ext_sort.rs
index 9b1845efa..d344df428 100644
--- a/src/uu/sort/src/ext_sort.rs
+++ b/src/uu/sort/src/ext_sort.rs
@@ -30,7 +30,7 @@ use crate::{
     compare_by, merge, output_sorted_lines, sort_by, GlobalSettings,
 };
 
-const MIN_BUFFER_SIZE: usize = 8_000;
+const START_BUFFER_SIZE: usize = 8_000;
 
 /// Sort files by using auxiliary files for storing intermediate chunks (if needed), and output the result.
 pub fn ext_sort(files: &mut impl Iterator<Item = Box<dyn Read + Send>>, settings: &GlobalSettings) {
@@ -132,7 +132,14 @@ fn reader_writer(
     for _ in 0..2 {
         chunks::read(
             &mut sender_option,
-            vec![0; MIN_BUFFER_SIZE],
+            vec![
+                0;
+                if START_BUFFER_SIZE < buffer_size {
+                    START_BUFFER_SIZE
+                } else {
+                    buffer_size
+                }
+            ],
             Some(buffer_size),
             &mut carry_over,
             &mut file,