# HG changeset patch
# User Markus Mützel <markus.muetzel@gmx.de>
# Date 1683389579 -7200
# Node ID a4fbcbaa0aa2cc8f9ee2f275b99dbca87876d087
# Parent  3c608abd55f5b98576c7ab4d76e06e6a4a18e410
rename: Consistent behavior cross-platform for existing target file (bug #63803).

* liboctave/system/file-ops.cc (octave::sys:rename): Manually enforce
consistent behavior on different platforms because the STL allow implementation
defined behavior if the target already exists.

diff -r 3c608abd55f5 -r a4fbcbaa0aa2 liboctave/system/file-ops.cc
--- a/liboctave/system/file-ops.cc	Sat May 06 17:48:27 2023 +0200
+++ b/liboctave/system/file-ops.cc	Sat May 06 18:12:59 2023 +0200
@@ -569,6 +569,26 @@
 
   msg = "";
 
+  // Do nothing if source and target are the same file.
+  if (same_file (to, from))
+    return 0;
+
+  // The behavior of std::rename with existing target is not defined by the
+  // standard.  Implementations differ vastly.  For Octave, use the following
+  // for the case that the target already exists:
+  // If the source and the target are regular files, overwrite the target.
+  // In other cases, fail.
+  if (file_exists (to))
+    {
+      if (file_exists (to, false) && file_exists (from, false))
+        unlink (to);
+      else
+        {
+          msg = "Target already exists.";
+          return status;
+        }
+    }
+
 #if defined (OCTAVE_USE_WINDOWS_API)
   std::wstring wfrom = u8_to_wstring (from);
   std::wstring wto = u8_to_wstring (to);