tr: don't truncate when not translating

An additional issue was found while reviewing #6340, check [this thread][1]. A summary is:

- `tr` ignores the `-t`/`--truncate-set1` flag when not translating
- Not translating is defined as `-d` was passed, or one set was passed.

[1]: https://github.com/uutils/coreutils/pull/6340#discussion_r1590007053

src/uu/tr/src/tr.rs

@@ -111,11 +111,15 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let locked_stdout = stdout.lock();
     let mut buffered_stdout = BufWriter::new(locked_stdout);
 
+    // According to the man page: translating only happens if deleting or if a second set is given
+    let translating = !delete_flag && sets.len() > 1;
     let mut sets_iter = sets.iter().map(|c| c.as_str());
     let (set1, set2) = Sequence::solve_set_characters(
         sets_iter.next().unwrap_or_default().as_bytes(),
         sets_iter.next().unwrap_or_default().as_bytes(),
-        truncate_set1_flag,
+        complement_flag,
+        // if we are not translating then we don't truncate set1
+        truncate_set1_flag && translating,
     )?;
 
     // '*_op' are the operations that need to be applied, in order.

tests/by-util/test_tr.rs

@@ -2,7 +2,7 @@
 //
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
-// spell-checker:ignore aabbaa aabbcc aabc abbb abbbcddd abcc abcdefabcdef abcdefghijk abcdefghijklmn abcdefghijklmnop ABCDEFGHIJKLMNOPQRS abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFZZ abcxyz ABCXYZ abcxyzabcxyz ABCXYZABCXYZ acbdef alnum amzamz AMZXAMZ bbbd cclass cefgm cntrl compl dabcdef dncase Gzabcdefg PQRST upcase wxyzz xdigit XXXYYY xycde xyyye xyyz xyzzzzxyzzzz ZABCDEF Zamz Cdefghijkl Cdefghijklmn
+// spell-checker:ignore aabbaa aabbcc aabc abbb abbbcddd abcc abcdefabcdef abcdefghijk abcdefghijklmn abcdefghijklmnop ABCDEFGHIJKLMNOPQRS abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFZZ abcxyz ABCXYZ abcxyzabcxyz ABCXYZABCXYZ acbdef alnum amzamz AMZXAMZ bbbd cclass cefgm cntrl compl dabcdef dncase Gzabcdefg PQRST upcase wxyzz xdigit XXXYYY xycde xyyye xyyz xyzzzzxyzzzz ZABCDEF Zamz Cdefghijkl Cdefghijklmn asdfqqwweerr qwerr asdfqwer qwer aassddffqwer asdfqwer
 use crate::common::util::TestScenario;
 
 #[test]
@@ -1334,3 +1334,33 @@ fn check_regression_issue_6163_match() {
         .no_stderr()
         .stdout_only("Z\n");
 }
+
+#[test]
+fn check_ignore_truncate_when_deleting_and_squeezing() {
+    new_ucmd!()
+        .args(&["-dts", "asdf", "qwe"])
+        .pipe_in("asdfqqwweerr\n")
+        .succeeds()
+        .no_stderr()
+        .stdout_only("qwerr\n");
+}
+
+#[test]
+fn check_ignore_truncate_when_deleting() {
+    new_ucmd!()
+        .args(&["-dt", "asdf"])
+        .pipe_in("asdfqwer\n")
+        .succeeds()
+        .no_stderr()
+        .stdout_only("qwer\n");
+}
+
+#[test]
+fn check_ignore_truncate_when_squeezing() {
+    new_ucmd!()
+        .args(&["-ts", "asdf"])
+        .pipe_in("aassddffqwer\n")
+        .succeeds()
+        .no_stderr()
+        .stdout_only("asdfqwer\n");
+}