Ensure extendedGlob returns paths in lexical order

copier/copier.go

@@ -14,6 +14,7 @@ import (
 	"path"
 	"path/filepath"
 	"slices"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -48,6 +49,7 @@ func init() {
 // "**" component in the pattern, filepath.Glob() will be called with the "**"
 // replaced with all of the subdirectories under that point, and the results
 // will be concatenated.
+// The matched paths are returned in lexical order, which makes the output deterministic.
 func extendedGlob(pattern string) (matches []string, err error) {
 	subdirs := func(dir string) []string {
 		var subdirectories []string
@@ -113,6 +115,7 @@ func extendedGlob(pattern string) (matches []string, err error) {
 		}
 		matches = append(matches, theseMatches...)
 	}
+	sort.Strings(matches)
 	return matches, nil
 }
 

copier/copier_test.go

@@ -2025,3 +2025,18 @@ func TestExtendedGlob(t *testing.T) {
 	require.NoError(t, err, "globbing")
 	require.ElementsMatch(t, expected2, matched, "**/d/**/*.dat")
 }
+
+func TestSortedExtendedGlob(t *testing.T) {
+	tmpdir := t.TempDir()
+	buf := []byte("buffer")
+	expect := []string{}
+	for _, name := range []string{"z", "y", "x", "a", "b", "c", "d", "e", "f"} {
+		require.NoError(t, os.WriteFile(filepath.Join(tmpdir, name), buf, 0o600))
+		expect = append(expect, filepath.Join(tmpdir, name))
+	}
+	sort.Strings(expect)
+
+	matched, err := extendedGlob(filepath.Join(tmpdir, "*"))
+	require.NoError(t, err, "globbing")
+	require.ElementsMatch(t, expect, matched, "sorted globbing")
+}