From b22a11789294f30dcf043187d68a27bdcd6a2eaf Mon Sep 17 00:00:00 2001
From: Jeffrey Finkelstein <jeffrey.finkelstein@protonmail.com>
Date: Mon, 6 Jun 2022 09:46:15 -0400
Subject: [PATCH] mktemp: error on empty --suffix in some situations

Make `mktemp` exit with an error if the `--suffix` option is the empty
string and the template argument does not end in an "X". Previously,
the program succeeded.

Before this commit,

    $ mktemp --suffix= aXXXb
    apBEb

After this commit,

    $ mktemp --suffix= aXXXb
    mktemp: with --suffix, template 'aXXXb' must end in X
---
 src/uu/mktemp/src/mktemp.rs  | 8 ++++----
 tests/by-util/test_mktemp.rs | 9 +++++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/uu/mktemp/src/mktemp.rs b/src/uu/mktemp/src/mktemp.rs
index 78e36874ea6..7d1c4a55d8f 100644
--- a/src/uu/mktemp/src/mktemp.rs
+++ b/src/uu/mktemp/src/mktemp.rs
@@ -279,15 +279,15 @@ impl Params {
         //
         // For example, if the suffix command-line argument is ".txt" and
         // the template is "XXXabc", then `suffix` is "abc.txt".
-        let suffix_from_option = options.suffix.unwrap_or_else(|| "".to_string());
         let suffix_from_template = &options.template[j..];
+        if !suffix_from_template.is_empty() && options.suffix.is_some() {
+            return Err(MkTempError::MustEndInX(options.template));
+        }
+        let suffix_from_option = options.suffix.unwrap_or_else(|| "".to_string());
         let suffix = format!("{}{}", suffix_from_template, suffix_from_option);
         if suffix.contains(MAIN_SEPARATOR) {
             return Err(MkTempError::SuffixContainsDirSeparator(suffix));
         }
-        if !suffix_from_template.is_empty() && !suffix_from_option.is_empty() {
-            return Err(MkTempError::MustEndInX(options.template));
-        }
 
         // The number of random characters in the template.
         //
diff --git a/tests/by-util/test_mktemp.rs b/tests/by-util/test_mktemp.rs
index df630e715a4..67c075827da 100644
--- a/tests/by-util/test_mktemp.rs
+++ b/tests/by-util/test_mktemp.rs
@@ -619,3 +619,12 @@ fn test_three_contiguous_wildcard_blocks() {
     assert_matches_template!(template, filename);
     assert!(at.file_exists(filename));
 }
+
+/// Test that template must end in X even if `--suffix` is the empty string.
+#[test]
+fn test_suffix_must_end_in_x() {
+    new_ucmd!()
+        .args(&["--suffix=", "aXXXb"])
+        .fails()
+        .stderr_is("mktemp: with --suffix, template 'aXXXb' must end in X\n");
+}