Re: Getting HEAD revision number from a URL

[Michael Sperber <sp...@informatik.uni-tuebingen.de>]

>>>>> "Ben" == Ben Collins-Sussman <su...@collab.net> writes:

Ben> We call this the "last changed revision" of a path.  In some sense,
Ben> it's a bit like the 'latest version' of a file or dir.

Ben>     * 'svn info working-copy-path' shows this.  Of course, be sure to
Ben> 'svn up' first.
Ben>     * 'svn list --verbose URL' shows this also.

What about if the file has been deleted and I want to to know the last
revision in which it still existed?  (Or the rev of the delete, for
that matter.)

-- 
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla

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Re: Getting HEAD revision number from a URL

[Julian Foad <ju...@btopenworld.com>]

Michael Sperber wrote:
>>>>>>"Ben" == Ben Collins-Sussman <su...@collab.net> writes:
> Ben> On Oct 29, 2004, at 4:26 AM, Michael Sperber wrote:
>>>What about if the file has been deleted and I want to to know the last
>>>revision in which it still existed?  (Or the rev of the delete, for
>>>that matter.)
> 
> Ben> Run 'svn log -v' on the parent directory (or any of its parent
> Ben> directories), and grep for the delete action.
> 
> Except the delete action might just show some parent directory only.

Yes.  This is a very interesting and difficult question.  I don't think we have 
a good answer at the moment.  There are some things we could do in the software 
to improve the situation.

It is actually an ambiguous question, with two interpretations.  Do you want to 
find:

(a) The last revision in which a file (any file) existed at (or was deleted 
from) the specified path?

   We have no efficient way of answering this question.  The best I can think 
of would be to search the output of "svn log -v" of the whole repository for 
deletion (or move or replacement) of the given path or any parent of it.

   To generalise this question, it is also necessary to be able to ask when the 
path last existed prior to a given revision.  (You could do this by searching 
the output of "svn log -v -rREV:1".)

(b) The last revision in which the particular specified file existed?

   For this question, first you have to specify the file rather than just its 
pathname.  You can do this (for some commands) with the "peg revision" syntax: 
"path/to/file@REV", meaning the file that existed at the given path in the 
given revision.  Note that the file might have been copied or moved from a 
different path before REV, and might have been copied or moved to a different 
path after REV.  Note that "REV" is necessarily a revision in which the file 
existed before it was deleted, otherwise you are asking question (a).

   Then you have to search forward in history, following moves and copies, 
until the file is deleted or replaced.  Note that the answer to this question 
is a list of "path@REV" answers, depending on how many times the file was copied.

   I think this task could be performed by a script using "svn log" in a 
forward direction: "svn log -v -rREV:HEAD".


SUMMARY

Each of these questions can be answered, inefficiently, by a script using "svn 
log" on the root of the repository.  If someone writes such a script, it would 
be nice to distribute it as a contributed tool, at least while we don't have a 
"proper" way.

Question (a):  I am not sure whether we would want to make a proper software 
interface for asking this question.

Question (b):  I think we should implement peg revisions and forward searching 
in commands like "svn log" so that this question is handled.  The details need 
to be determined - e.g. whether and how it would follow all copies.  As an 
implementation detail, tracing files forward is inefficient in the current 
software architecture, but I think some work may already have been done, or at 
least suggested, to improve that.

- Julian

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Re: Getting HEAD revision number from a URL

[Michael Sperber <sp...@informatik.uni-tuebingen.de>]

>>>>> "Ben" == Ben Collins-Sussman <su...@collab.net> writes:

Ben> On Oct 29, 2004, at 4:26 AM, Michael Sperber wrote:

>> What about if the file has been deleted and I want to to know the last
>> revision in which it still existed?  (Or the rev of the delete, for
>> that matter.)

Ben> Run 'svn log -v' on the parent directory (or any of its parent
Ben> directories), and grep for the delete action.

Except the delete action might just show some parent directory only.

-- 
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla

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Re: Getting HEAD revision number from a URL

[Ben Collins-Sussman <su...@collab.net>]

On Oct 29, 2004, at 4:26 AM, Michael Sperber wrote:

>
>>>>>> "Ben" == Ben Collins-Sussman <su...@collab.net> writes:
>
> Ben> We call this the "last changed revision" of a path.  In some 
> sense,
> Ben> it's a bit like the 'latest version' of a file or dir.
>
> Ben>     * 'svn info working-copy-path' shows this.  Of course, be 
> sure to
> Ben> 'svn up' first.
> Ben>     * 'svn list --verbose URL' shows this also.
>
> What about if the file has been deleted and I want to to know the last
> revision in which it still existed?  (Or the rev of the delete, for
> that matter.)
>

Run 'svn log -v' on the parent directory (or any of its parent 
directories), and grep for the delete action.


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