describe-variable gets the defining library wrong

describe-variable gets the defining library wrong

[Drew Adams]

I haven't found a recipe to reproduce this, but it happens to me quite often
with Emacs 23: `describe-variable' says "foo is a variable defined in `bar.el'"
when foo is not defined in `bar.el' at all, or at least not most recently.

I've even seen it happen when `bar.el' has only a byte-compiler quieter sexp,
such as this, which should hardly count as a definition: (defvar foo). This is a
mystery, to me.

I've also seen "defined in `.emacs'", when that is not at all where the variable
is defined. I suppose this is a fallback (copout), if Emacs can't tell where the
variable was really defined. That's understandable, I guess. (But not very
useful, and still misleading - maybe it's better to say nothing if we know
nothing.)

But saying that the current definition is in library bar.el when it was last
defined in toto.el is wrong. Emacs has always had some degree of difficulty
reporting this, but it seems like this has gotten worse in Emacs 23.

Does anyone else see this behavior, or is it just me? Sorry I don't have a
recipe to reproduce this yet.

Re: describe-variable gets the defining library wrong

[Stefan Monnier]

> Does anyone else see this behavior, or is it just me? Sorry I don't have a
> recipe to reproduce this yet.

Doesn't ring a bell.  Please report it again with more details next time
you see it.


        Stefan

RE: describe-variable gets the defining library wrong

[Drew Adams]

> > Does anyone else see this behavior, or is it just me? Sorry 
> > I don't have a recipe to reproduce this yet.
> 
> Doesn't ring a bell.  Please report it again with more 
> details next time you see it.

Put this in a new file foobar.el:

(defvar text-scale-mode-amount) ; Quiet byte-compiler < Emacs 23

Byte-compile foobar.el using Emacs 20 or 21.

emacs -Q  ; Emacs 23

M-x load-library face-remap
M-x load-file foobar.elc
C-h v text-scale-mode-amount

You'll see this:

,----
| text-scale-mode-amount is a variable defined in `foobar.el'.
| Its value is 0
| 
|   Automatically becomes buffer-local when set in any fashion.
| 
| Documentation:
| Not documented as a variable.
`----

Re: describe-variable gets the defining library wrong

[Stefan Monnier]

> Byte-compile foobar.el using Emacs 20 or 21.

Well, now, as you know, Emacs's backward compatibility is not 100%.
So, no, it's not considered a bug (other than a bug in Emacs-21, maybe).


        Stefan