Merge pull request #4931 from cazou/improve-tsort

tsort: Switch to BTreeMap and BTreeSet

src/uu/tsort/src/tsort.rs

@@ -6,7 +6,7 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 use clap::{crate_version, Arg, Command};
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeMap, BTreeSet};
 use std::fs::File;
 use std::io::{stdin, BufRead, BufReader, Read};
 use std::path::Path;
@@ -103,8 +103,8 @@ pub fn uu_app() -> Command {
 // but using integer may improve performance.
 #[derive(Default)]
 struct Graph {
-    in_edges: HashMap<String, HashSet<String>>,
-    out_edges: HashMap<String, Vec<String>>,
+    in_edges: BTreeMap<String, BTreeSet<String>>,
+    out_edges: BTreeMap<String, Vec<String>>,
     result: Vec<String>,
 }
 
@@ -122,7 +122,7 @@ impl Graph {
     }
 
     fn init_node(&mut self, n: &str) {
-        self.in_edges.insert(n.to_string(), HashSet::new());
+        self.in_edges.insert(n.to_string(), BTreeSet::new());
         self.out_edges.insert(n.to_string(), vec![]);
     }
 

tests/by-util/test_tsort.rs

@@ -20,6 +20,14 @@ fn test_sort_self_loop() {
         .stdout_only("first\nsecond\n");
 }
 
+#[test]
+fn test_sort_floating_nodes() {
+    new_ucmd!()
+        .pipe_in("d d\nc c\na a\nb b")
+        .succeeds()
+        .stdout_only("a\nb\nc\nd\n");
+}
+
 #[test]
 fn test_no_such_file() {
     new_ucmd!()