bug#37922: Acknowledgement (26.3; move-file-to-trash puts wrong trash file name at name collision)

[Shingo Tanaka]

# Resending it as I sent the original mail in HTML format by mistake...

Hi,

When delete-by-moving-to-trash is t and system-move-file-to-trash is not 
defined, move-file-to-trash moves the deleted file to system trash can 
following freedesktop.org trash can specification.

In this condition, when a file is deleted and it has the same name as the one 
of an already deleted file in trash can, move-file-to-trash generates another 
file name by using make-temp-file to avoid the name collision.  Unfortunatelly, 
it does the naming in a wrong way.

For example, when 2 "hoge.txt" are deleted, expected files are like:

/home/myusername/.local/share/Trash/files:
-rw-rw-rw- 1 myusername  10 2019-10-25 20:00 hoge.txt
-rw-rw-rw- 1 myusername  10 2019-10-25 20:00 hoge.txtwmWP0h

/home/myusername/.local/share/Trash/info:
-rw-rw-rw- 1 myusername  75 2019-10-25 20:00 hoge.txt.trashinfo
-rw------- 1 myusername  75 2019-10-25 20:00 hoge.txtwmWP0h.trashinfo

However, the reality is the 2nd trash file in files directory is named wrongly 
with ".trashinfo" suffix like:

/home/myusername/.local/share/Trash/files:
-rw-rw-rw- 1 myusername  10 2019-10-25 20:00 hoge.txt
-rw-rw-rw- 1 myusername  10 2019-10-25 20:00 hoge.txtwmWP0h.trashinfo
                                                            ^^^^^^^^^
/home/myusername/.local/share/Trash/info:
-rw-rw-rw- 1 myusername  75 2019-10-25 20:00 hoge.txt.trashinfo
-rw------- 1 myusername  75 2019-10-25 20:00 hoge.txtwmWP0h.trashinfo

Here is a potential patch.

--- files.el.original   2019-09-17 05:14:45.000000000 +0900
+++ files.el    2019-10-25 20:52:13.899138800 +0900
@@ -7408,7 +7408,8 @@
                    (setq info-fn (make-temp-file
                                   (expand-file-name files-base trash-info-dir)
                                   nil ".trashinfo"))
-                   (setq files-base (file-name-nondirectory info-fn))
+                   (setq files-base (substring (file-name-nondirectory info-fn)
+                                               0 (- (length ".trashinfo"))))
                    (write-region nil nil info-fn nil 'quiet info-fn)))
                 ;; Finally, try to move the file to the trashcan.
                 (let ((delete-by-moving-to-trash nil)

---
Shingo Tanaka