bug#4592: Bug in built-in function substitute-in-file-name

bug#4592: Bug in built-in function substitute-in-file-name

[Mosur Mohan]

I am running Emacs version 21.3 on a Linux x86_64 machine.

When I start up Emacs, I go to the *scratch* buffer and eval
    (substitute-in-file-name "/~/")
and I get the expected result
    "~/"

After running for a while, I notice that filename completion starts
giving errors.  At this point, I re-try the above experiment:
    (substitute-in-file-name "/~/")
But now, I get:
    "/~/"

I am not able to figure out what happened in between to make it stop
working correctly.  A search for "substitute-in-file-name" in
bug.gnu.emacs didn't turn up anything relevant to this problem.

I narrowed the problem down to substitute-in-file-name after some
debugging.  Here's the sequence:

In the recently launched Emacs session, while editing a file, I type
C-x C-f to open another file.
In the minibuffer, I see the prompt "~/DesignDB/" (my current working directory)
I type "~/Al" so that the minibuffer now reads "~/DesignDB/~/Al"
I hit <TAB> to do completion on ~/Al
The minibuffer changes to "~/Alps/", which is correct.

In the older Emacs session where I see the problem, I carry out the
same sequence.
With the minibuffer reading "~/DesignDB/~/Al", I hit <TAB>
The minibuffer shows this message: "Opening directory: no such file or
directory, /nfs/pdx/home/mmohan/DesignDB/~*/Al"
The *Messages* window contains this message:
read-file-name-internal: Opening directory: no such file or directory,
/nfs/pdx/home/mmohan/DesignDB/~*/

I debugged this difference in complete.el and ffap.el until I reached
the above discrepancy in the behavior of built-in function
substitute-in-file-name.  I was then able to make the 2 sessions
exhibit the difference with the minimal arg "/~/" to the function.

Hope that is sufficient info.  Thanks,
--
Mosur Mohan

bug#4592: Bug in built-in function substitute-in-file-name

[Andreas Schwab]

Mosur Mohan <mognush@gmail.com> writes:

> When I start up Emacs, I go to the *scratch* buffer and eval
>     (substitute-in-file-name "/~/")
> and I get the expected result
>     "~/"
>
> After running for a while, I notice that filename completion starts
> giving errors.  At this point, I re-try the above experiment:
>     (substitute-in-file-name "/~/")
> But now, I get:
>     "/~/"
>
> I am not able to figure out what happened in between to make it stop
> working correctly.

What does
 (find-file-name-handler "/~/" 'substitute-in-file-name)
return?

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

bug#4592: Bug in built-in function substitute-in-file-name

[Mosur Mohan]

> What does
>  (find-file-name-handler "/~/" 'substitute-in-file-name)
> return?

In both Emacs sessions, it returns nil.
--
Mohan

On Wed, Sep 30, 2009 at 2:07 AM, Andreas Schwab <schwab@linux-m68k.org> wrote:
> Mosur Mohan <mognush@gmail.com> writes:
>
>> When I start up Emacs, I go to the *scratch* buffer and eval
>>     (substitute-in-file-name "/~/")
>> and I get the expected result
>>     "~/"
>>
>> After running for a while, I notice that filename completion starts
>> giving errors.  At this point, I re-try the above experiment:
>>     (substitute-in-file-name "/~/")
>> But now, I get:
>>     "/~/"
>>
>> I am not able to figure out what happened in between to make it stop
>> working correctly.
>
> What does
>  (find-file-name-handler "/~/" 'substitute-in-file-name)
> return?
>
> Andreas.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
>

bug#4592: Bug in built-in function substitute-in-file-name

[Glenn Morris]

Mosur Mohan wrote:

> I am running Emacs version 21.3 on a Linux x86_64 machine.
[...]
> After running for a while, I notice that filename completion starts
> giving errors.  At this point, I re-try the above experiment:
>     (substitute-in-file-name "/~/")
> But now, I get:
>     "/~/"

Unfortunately, this seems a rather obscure problem, and Emacs 21 is
quite old, so you are unlikely to get much help unless you can give a
simple recipe showing how to get into this state (starting from emacs
-q --no-site-file). In any case, I would recommend upgrading to Emacs 23.

bug#4592: Bug in built-in function substitute-in-file-name

[Mosur Mohan]

I was afraid you were gonna say that... :-) Unfortunately I haven't
been able to pin down the exact recipe; in the "good" session, I'm
still chugging along and the error hasn't occurred yet.

Thanks for your help anyway!  If I figure out the recipe to trigger
this behavior, I will get in touch with you again.
--
Mohan

On Fri, Oct 2, 2009 at 5:15 PM, Glenn Morris <rgm@gnu.org> wrote:
> Mosur Mohan wrote:
>
>> I am running Emacs version 21.3 on a Linux x86_64 machine.
> [...]
>> After running for a while, I notice that filename completion starts
>> giving errors.  At this point, I re-try the above experiment:
>>     (substitute-in-file-name "/~/")
>> But now, I get:
>>     "/~/"
>
> Unfortunately, this seems a rather obscure problem, and Emacs 21 is
> quite old, so you are unlikely to get much help unless you can give a
> simple recipe showing how to get into this state (starting from emacs
> -q --no-site-file). In any case, I would recommend upgrading to Emacs 23.
>

bug#4592: Bug in built-in function substitute-in-file-name

[Lennart Borgman]

Why do you do that instead of upgrade to Emacs 23?


On Sat, Oct 3, 2009 at 9:13 AM, Mosur Mohan <mognush@gmail.com> wrote:
> I was afraid you were gonna say that... :-) Unfortunately I haven't
> been able to pin down the exact recipe; in the "good" session, I'm
> still chugging along and the error hasn't occurred yet.
>
> Thanks for your help anyway!  If I figure out the recipe to trigger
> this behavior, I will get in touch with you again.
> --
> Mohan
>
> On Fri, Oct 2, 2009 at 5:15 PM, Glenn Morris <rgm@gnu.org> wrote:
>> Mosur Mohan wrote:
>>
>>> I am running Emacs version 21.3 on a Linux x86_64 machine.
>> [...]
>>> After running for a while, I notice that filename completion starts
>>> giving errors.  At this point, I re-try the above experiment:
>>>     (substitute-in-file-name "/~/")
>>> But now, I get:
>>>     "/~/"
>>
>> Unfortunately, this seems a rather obscure problem, and Emacs 21 is
>> quite old, so you are unlikely to get much help unless you can give a
>> simple recipe showing how to get into this state (starting from emacs
>> -q --no-site-file). In any case, I would recommend upgrading to Emacs 23.
>>
>
>
>
>

bug#4592: Bug in built-in function substitute-in-file-name

[Mosur Mohan]

Sorry, didn't notice your question earlier... yes, I will upgrade at
least to 22.3 (that is the latest version that our IT group has
installed internally). But I have quite a bit of customization, which
takes a while to transition, so it will probably be some time before I
can switch versions.  So, if I notice the bug before that happens,
maybe I can figure out what triggers it -- that's what I meant.

Thanks,
--
Mohan


On Sat, Oct 3, 2009 at 12:18 PM, Lennart Borgman
<lennart.borgman@gmail.com> wrote:
> Why do you do that instead of upgrade to Emacs 23?
>
>
> On Sat, Oct 3, 2009 at 9:13 AM, Mosur Mohan <mognush@gmail.com> wrote:
>> I was afraid you were gonna say that... :-) Unfortunately I haven't
>> been able to pin down the exact recipe; in the "good" session, I'm
>> still chugging along and the error hasn't occurred yet.
>>
>> Thanks for your help anyway!  If I figure out the recipe to trigger
>> this behavior, I will get in touch with you again.
>> --
>> Mohan
>>
>> On Fri, Oct 2, 2009 at 5:15 PM, Glenn Morris <rgm@gnu.org> wrote:
>>> Mosur Mohan wrote:
>>>
>>>> I am running Emacs version 21.3 on a Linux x86_64 machine.
>>> [...]
>>>> After running for a while, I notice that filename completion starts
>>>> giving errors.  At this point, I re-try the above experiment:
>>>>     (substitute-in-file-name "/~/")
>>>> But now, I get:
>>>>     "/~/"
>>>
>>> Unfortunately, this seems a rather obscure problem, and Emacs 21 is
>>> quite old, so you are unlikely to get much help unless you can give a
>>> simple recipe showing how to get into this state (starting from emacs
>>> -q --no-site-file). In any case, I would recommend upgrading to Emacs 23.
>>>
>>
>>
>>
>>
>

bug#4592: Bug in built-in function substitute-in-file-name

[Glenn Morris]

Thanks for the report. Your report was against an old version of Emacs,
and the issue you describe could not be reproduced. The latest version
is 23.3. Please open new reports for any issues you have with the new
version.