[darcs-users] Google Summer of Code 2009 - ideas, students and mentors?

Petr Rockai me at mornfall.net
Thu Feb 12 17:14:06 UTC 2009

Gwern Branwen <gwern0 at gmail.com> writes:
> Is that very hard? filestore has that functionality, after all. IIRC,
> it was basically 'darcs changes --from-match="hash foo"
> --to-match="hash foo" file'.
That works fine if you have couple hundred patches maybe. For real-world big
repositories, it's a performance no-go (at least if the from-match is far back
in history). The same issue as with darcs annotate, really. Also, this doesn't
produce a diff, just a list of changes. For real (unified) diff, darcs needs to
make two copies of the repository in /tmp and run GNU diff against them. This
won't fly with a hundred-megabyte repo either.

In other words, this does need addressing on at least two fronts, first
per-file list of patches is very inefficient. Second, producing real diffs (not
the darcs internal format) is rather slow and is O(repository_size) even for
single files.


Peter Rockai | me()mornfall!net | prockai()redhat!com
 http://blog.mornfall.net | http://web.mornfall.net

"In My Egotistical Opinion, most people's C programs should be
 indented six feet downward and covered with dirt."
     -- Blair P. Houghton on the subject of C program indentation

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