Re: Bug in Custom apparently due to Custom Themes.

[Luc Teirlinck]

Chong Yidong wrote:

   > Start Emacs, assuming that fill-column is at its standard value of 70
   > and do
   >
   > M-: (setq-default fill-column 71)
   >
   > `M-x customize-option fill-column RET'
   >
   > Edit to 72 and set for current session, using the State Menu.
   >
   > Then choose "Erase Customization" from the State Menu.
   >
   > The value should now be 70 and the State STANDARD.
   >
   > Instead, the value is 71 and we see:
   >
   > CHANGED outside Customize; operating on it here may be unreliable.

   I don't see the problem: the value 71 is the last value that
   fill-column had before it was changed with customize.  That's why
   erasing customizations brings back this value.

Do you use Custom at all?  The problem is so obvious that I do not
know what there is to explain.  "Erase Customization" is supposed to
restore the standard value (or themed value if there are themes) and
_not_ the last _rogue_ value assigned to the variable, which may have
been assigned ages ago, and changed twenty times through Custom since.
That value is meaningless, which is why that `changed' theme is
completely meaningless and should be eliminated.

What I described above constitutes an incompatible change, which
eliminates completely essential and well documented functionality
(reverting to the default) and replaces it with nonsensical behavior.
It is a serious bug.

Sincerely,

Luc.