dircolors: fix empty COLORTERM matching with ?* pattern

should fix tests/misc/dircolors

src/uu/dircolors/src/dircolors.rs

@@ -374,6 +374,7 @@ where
 
     let term = env::var("TERM").unwrap_or_else(|_| "none".to_owned());
     let term = term.as_str();
+    let colorterm = env::var("COLORTERM").unwrap_or_default();
 
     let mut state = ParseState::Global;
 
@@ -396,8 +397,20 @@ where
             ));
         }
         let lower = key.to_lowercase();
+
         if lower == "term" || lower == "colorterm" {
-            if term.fnmatch(val) {
+            let should_match = if lower == "colorterm" {
+                // For COLORTERM ?*, only match if COLORTERM is non-empty
+                if val == "?*" {
+                    !colorterm.is_empty()
+                } else {
+                    colorterm.fnmatch(val)
+                }
+            } else {
+                term.fnmatch(val)
+            };
+
+            if should_match {
                 state = ParseState::Matched;
             } else if state != ParseState::Matched {
                 state = ParseState::Pass;

tests/by-util/test_dircolors.rs

@@ -253,3 +253,14 @@ fn test_repeated() {
         new_ucmd!().arg(arg).arg(arg).succeeds().no_stderr();
     }
 }
+
+#[test]
+fn test_colorterm_empty_with_wildcard() {
+    new_ucmd!()
+        .env("COLORTERM", "")
+        .pipe_in("COLORTERM ?*\nowt 40;33\n")
+        .args(&["-b", "-"])
+        .succeeds()
+        .stdout_is("LS_COLORS='';\nexport LS_COLORS\n")
+        .no_stderr();
+}