bug#82186: mv --exchange prints "Unknown error -1" instead of "No such file or directory" when destination does not exist

[Pádraig Brady]

On 05/11/2026 03:00, Collin Funk wrote:

Collin Funk <collin.fu...@gmail.com> writes:

Thanks for the detailed report!

I can reproduce it on coreutils-9.12 as well. I'll take a look at it
later today.

This patch should do the trick. The issue also occurs with target
directories, i.e., the following commands:

     $ touch a; mkdir -p b
     $ mv --exchange a b
     mv: cannot exchange 'a' and 'b/a': Unknown error -1
     $ mv --exchange --target-directory=b a
     mv: cannot exchange 'a' and 'b/a': Unknown error -1

So, I've added test cases for those and the more common invocation that
you shared.

I'll push it tomorrow to allow others a chance to review.

Thanks again for the report,
Collin

I'd s/EEXIST/ENOENT/ in the commit summary.
I'd mention the error in the commit message to
help folks looking for a solution, something like:

  mv: cannot exchange 'exist' and 'missing': Unknown error -1

I'd also adjust the source comment like:

diff --git a/src/copy.c b/src/copy.c
index cfd9deaad..273ed676f 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -1749,9 +1749,8 @@ copy_internal (char const *src_name, char const *dst_name,
             }
           else if (errno == ENOENT)
             {
-              /* Using renameatu would fail with ENOENT as well.
-                 Prefer the error message describing the failed rename
-                 instead of the failed stat.  */
+              /* Using RENAME_EXCHANGE would fail with ENOENT as well,
+                 so set accordingly for that implied but skipped renamatu().  
*/
               if (x->exchange)
                 rename_errno = ENOENT;
               new_dst = true;

The tests may fail where RENAME_EXCHANGE returns ENOTSUP I think.
In that case it's better to use a separate directory for the ENOENT test:

diff --git a/tests/mv/mv-exchange.sh b/tests/mv/mv-exchange.sh
index cd237dcb0..42846c638 100755
--- a/tests/mv/mv-exchange.sh
+++ b/tests/mv/mv-exchange.sh
@@ -49,9 +49,10 @@ compare /dev/null out || fail=1
 compare exp-err err || fail=1

 # Test the behavior with a missing destination in a target directory.
-echo "mv: cannot exchange 'b' and 'a/b': $ENOENT" >exp-err || 
framework_failure_
+mkdir d || framework_failure_
+echo "mv: cannot exchange 'b' and 'd/b': $ENOENT" >exp-err || 
framework_failure_
 for opt in '' --target-directory=; do
-  returns_ 1 mv --exchange b ${opt}a >out 2>err || fail=1
+  returns_ 1 mv --exchange b ${opt}d >out 2>err || fail=1
   compare /dev/null out || fail=1
   compare exp-err err || fail=1
 done

cheers,
Padraig